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Side by side comparison of UMD tree cover loss and JRC Tropical Moist Forest data

Data &amp; Tools

Data &amp; Tools | Global Forest Watch Blog

deforestation

deforestation | Global Forest Watch Blog

forest change

forest change | Global Forest Watch Blog

forest quality

forest quality | Global Forest Watch Blog

mapping

mapping | Global Forest Watch Blog

Michelle Sims

Peter Potapov

Christelle Vancutsem

Clément Bourgoin

Fréderic Achard

Sarah Carter

<p>The wide availability of forest and land cover maps based on satellite data provides more information on the world’s forests than ever before. However, this plethora of information can also be challenging for people trying to understand differences in data sources and decide which data to use for a specific purpose.</p>



<p>In the past, we’ve compared the <a href="https://gfw.global/3BfwQWz">annual tree cover loss data</a> from the University of Maryland (UMD) and available on Global Forest Watch (GFW) with national data from <a href="https://www.globalforestwatch.org/blog/data-and-research/2022-tree-cover-loss-data-explained/">Brazil and Indonesia</a>, as well as with data from the United Nations Food and Agriculture Organization’s (FAO) <a href="https://www.globalforestwatch.org/blog/data-and-research/global-forest-watch-and-the-forest-resources-assessment-explained-in-5-graphics-2/">Global Forest Resources Assessment</a>, to shed light on some of these differences.</p>



<p>Another data set that tracks forest change in the tropics is the <a href="https://forobs.jrc.ec.europa.eu/TMF" target="_blank" rel="noreferrer noopener">Tropical Moist Forest (TMF) data set</a> from the European Commission Joint Research Centre (JRC). Like the UMD tree cover loss data, the JRC TMF data is based on Landsat satellite imagery and is updated annually. Yet while both data sets map forest disturbances, the maps and numbers look a little different.</p>



<p>In this blog, we explain some key differences in the definitions and methods used for each data set that impact the resulting maps and discuss how the disturbances mapped by both data sets compare (while the data sets also map forest gain or regrowth, this blog focuses on comparing their mapping of forest disturbances). While understanding these differences can help determine the contexts for which each data set might be useful, note that this analysis does not evaluate the quality or accuracy of either data set.</p>



<h2 class="wp-block-heading">What areas do the JRC and UMD data sets cover, and how do they define forests?</h2>



<p>The UMD data set maps forests globally based on <a href="https://www.science.org/doi/10.1126/science.1244693" target="_blank" rel="noreferrer noopener">tree cover extent</a> in 2000. <a href="https://www.science.org/doi/10.1126/science.1244693" target="_blank" rel="noreferrer noopener">Tree cover</a> is defined as woody vegetation with a minimum height of at least five meters at 30-meter resolution, which includes all types of tree cover — including natural or managed forest and plantations — and is not limited to a specific forest type. The GFW map shows tree cover with a 30% canopy density, which we use in our analyses and in this comparison, although users can adjust the threshold based on their needs.</p>



<p>The JRC data set, on the other hand, <a href="https://www.science.org/doi/10.1126/sciadv.abe1603" target="_blank" rel="noreferrer noopener">maps forests</a> beginning in 1990. The data includes all closed primary and secondary forests in the humid tropics and does not apply a minimum height or canopy density threshold to delineate forest extent.</p>



<p>As a result of these definitional differences, some areas included in the 2000 UMD tree cover extent in the tropics like dry forests, young secondary forests and plantations are not classified as forests in the JRC data set in 2000 — a total of 655 million hectares (Mha), or 34%, of the UMD tree cover extent area that overlaps with the JRC data. Likewise, the JRC forest extent in 2000 includes some areas that do not meet the height and 30% canopy density threshold in the UMD data or are otherwise not mapped as tree cover by the UMD data — 17.2 Mha, or 1% of the JRC forest extent.</p>



<p>Because of the differences in geographic coverage and scope between the two data sets, this blog only compares forest disturbances from 2001-2022 for areas that, in the year 2000, are mapped both as tree cover by UMD and as forest by JRC.</p>



<h2 class="wp-block-heading">What types of forest disturbances do the UMD and JRC data map?</h2>



<h3 class="wp-block-heading"><em>The JRC Tropical Moist Forest data set maps degradation and deforestation in the humid tropics</em></h3>



<p>The JRC TMF data set maps disturbances to tropical moist forests — including degradation and deforestation — from 1990 to 2022. The JRC team maps these changes using an algorithm that detects forest disruptions, meaning an absence of tree foliage cover within a 30-meter pixel for each available Landsat image, and then classifies the status of forest based on how long these disruptions are visible.</p>



<p>The TMF data set <a href="https://www.science.org/doi/10.1126/sciadv.abe1603" target="_blank" rel="noreferrer noopener">defines degradation</a> as temporary disturbances occurring for up to 2.5 years, while it defines deforestation as longer-term disturbances where disruptions to tree cover are visible for more than 2.5 years and no tree regrowth is detected over the last three years. In any given year, a forest is considered disturbed if there is a disruption detected in at least one Landsat image during that year.</p>



<p>Thus, pixels classified as degraded are still considered forest, with existing or regrowing trees, while pixels classified as deforested are undergoing a longer-term loss of forest. Because disruptions are recorded and analyzed for the entire time series, the data set classifies dynamics over time; for example, a forest pixel may be classified as degraded in one year after a short-term disturbance, then after a period of recovery may later be classified as deforested after ongoing disturbances with no tree regrowth. The JRC deforestation class therefore includes direct deforestation (deforestation of undisturbed forest) or deforestation after degradation (deforestation of forest that was previously classified as degraded).</p>



<p>The data set also analyzes the frequency, duration of disruptions and time of forest recovery in between disruption events to identify deforestation following degradation versus multiple degradation events.</p>



<h3 class="wp-block-heading"><em>The UMD tree cover loss data set on GFW maps all types of tree cover loss globally</em></h3>



<p>The UMD tree cover loss data set maps annual tree cover loss from 2001 to 2022. The UMD team uses an algorithm that detects loss using change detection metrics based on comparison of Landsat images between the present and past years. Tree cover loss, <a href="https://www.science.org/doi/10.1126/science.1244693" target="_blank" rel="noreferrer noopener">defined as</a> a clearing of tree cover of at least a half of a 30-meter Landsat pixel, includes both temporary and permanent losses without defining or differentiating which loss is considered degradation or deforestation. Once classified as loss, pixels are masked from further updates, meaning that any following forest change dynamics — such as regrowth or subsequent disturbances — are not recorded.</p>



<p>The UMD tree cover loss data can be combined with contextual data layers, such as <a href="https://gfw.global/3kqcoqa">UMD’s map of humid tropical primary forest</a>, to see loss within specific forest types.</p>



<h4 class="wp-block-heading">Key differences between the JRC TMF and UMD tree cover loss data</h4>



<table border="1" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td style="width:165px;height:20px;">
			<p>&nbsp;</p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>JRC TMF</strong></p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>UMD tree cover loss</strong></p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Temporal coverage</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>1990-2022</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>&nbsp;2000-2022</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Geographic coverage and extent</p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>Tropical moist forest:</strong> closed primary and secondary forests in the humid tropics in 1990.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>Global tree cover: </strong>woody vegetation with a minimum height of at least five meters at 30-meter resolution in 2000.</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Definition of disturbance</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>An absence of tree foliage cover within a 30-meter pixel.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Clearing of at least half of tree cover within a 30-meter pixel.</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Disturbance classes</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Disturbances are classified as <strong>degradation </strong>if they are visible for less than 2.5 years, and <strong>deforestation </strong>if they are visible for more than 2.5 years with no vegetative regrowth over the last three years.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>All disturbances classified as <strong>tree cover loss. </strong>The length of disturbance is not considered.</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Methods</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Classifies valid single-date Landsat images and derives disturbance classes by analyzing the single-date classifications. Dynamics of disturbance events over time are recorded.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Classifies change using change detection metrics derived from all valid Landsat images over the present and past years. Only the first loss event that is detected is recorded.</p>
			</td>
		</tr>
	</tbody>
</table>



<h2 class="wp-block-heading">What do the UMD and JRC data show about forest disturbances in the tropics?</h2>



<p>Overall, the JRC data detects a larger area of disturbances across the tropics from 2001-2022 compared with the UMD data. The JRC data detects 258 Mha of disturbances, including 113 Mha of degradation and 145 Mha of deforestation, while the UMD data detects 143 Mha of tree cover loss. However, trends in total deforestation mapped by JRC and tree cover loss mapped by UMD are generally aligned: They are largely similar for the first decade; then from 2013-2015, JRC detects a larger area as deforestation than UMD detects as loss, and after 2016, UMD detects a larger area.</p>



<div class="flourish-embed" data-src="story/2112582?163031"><script src="https://public.flourish.studio/resources/embed.js"></script></div>



<p>We further separated out the disturbance types mapped by the JRC data and overlaid the data sets to evaluate how the two data sets compare at each pixel.</p>



<p>Among all the JRC data’s disturbance classes, the JRC direct deforestation class aligned most closely with UMD tree cover loss. Across the tropics from 2001-2022, 46.8 Mha, or 68%, of the area classified as direct deforestation by the JRC data was also classified as tree cover loss in the UMD data. This varied by region and was highest in Asia/Oceania and the Americas (66% and 75% respectively) and lowest in Africa (50%). The UMD data less often classified areas that JRC identified as deforestation after degradation as tree cover loss (38.1 Mha, or 50% across the tropics).</p>



<p>In some areas, disturbances classified as degradation by the JRC TMF data set were classified as tree cover loss by the UMD data. Across the tropics from 2001-2022, 32.6 Mha, or 29%, of the area the JRC data classified as degradation was also classified as tree cover loss in the UMD data. The JRC degradation class includes three types of degradation: short-duration (less than one year), long-duration (1-2.5 years) and short-duration over 2-3 periods (short-duration degradation that occurs two to three separate times throughout the time period). The JRC data also measures “intensity” of degradation based on the total number of Landsat images where disruptions in tree cover were visible. We found that, in general, the UMD data:</p>



<ul>
<li>More often detected longer duration degradation as tree cover loss. Short-duration degradation (including events occurring just once or over 2-3 periods), which represents 85% of the forest area mapped as degraded by JRC since 2001, is usually not shown as tree cover loss by the UMD data.</li>



<li>Classified degradation events as tree cover loss that had an intensity of greater than six images on average, while those UMD did not classify as loss had approximately three images or less on average.</li>



<li>Detected a larger proportion of the area JRC classified as degradation from 2015 onwards, which may be <a href="https://www.globalforestwatch.org/blog/data-and-research/tree-cover-loss-satellite-data-trend-analysis/">due to the algorithm changes</a> in the UMD data that increase forest loss detection sensitivity in case of fires, selective logging and other disturbance types that JRC classified as degradation.</li>
</ul>



<p>In other areas across the tropics, the UMD data detected tree cover loss for 6.4 Mha, or 7%, of areas where there the JRC data detected no disturbance events.</p>



<figure class="wp-block-image size-full is-resized"><img decoding="async" loading="lazy" width="1222" height="1163" src="https://content.globalforestwatch.org/wp-content/uploads/2024/01/Comparison-JRC-TMF-and-UMD-table.png" alt="Comparison of JRC TMF and UMD tree cover loss disturbances across the tropics" class="wp-image-16572" style="aspect-ratio:1.0507308684436802;width:771px;height:auto" srcset="https://content.globalforestwatch.org/wp-content/uploads/2024/01/Comparison-JRC-TMF-and-UMD-table.png 1222w, https://content.globalforestwatch.org/wp-content/uploads/2024/01/Comparison-JRC-TMF-and-UMD-table-1024x975.png 1024w, https://content.globalforestwatch.org/wp-content/uploads/2024/01/Comparison-JRC-TMF-and-UMD-table-768x731.png 768w" sizes="(max-width: 1222px) 100vw, 1222px" /></figure>



<h4 class="wp-block-heading">Forest disturbances related to shifting cultivation in Mongala, DRC</h4>



<div class="flourish-embed flourish-photo-slider" data-src="visualisation/16055613?163031"><script src="https://public.flourish.studio/resources/embed.js"></script></div>



<h4 class="wp-block-heading">Large scale deforestation along BR-230 in Amazonas, Brazil</h4>



<div class="flourish-embed flourish-photo-slider" data-src="visualisation/16055698?163031"><script src="https://public.flourish.studio/resources/embed.js"></script></div>



<h4 class="wp-block-heading">Selective logging in Pará, Brazil</h4>



<div class="flourish-embed flourish-photo-slider" data-src="visualisation/16365261?163031"><script src="https://public.flourish.studio/resources/embed.js"></script></div>



<h2 class="wp-block-heading">Why does the UMD and JRC data align in some ways and differ in others?</h2>



<p>The two data sets align more closely for more abrupt disturbances that are likely to meet the definitions used in both data sets, such as intense fires (which the JRC data may classify as long-duration degradation) or clearance of tree cover for agricultural expansion (usually classified as deforestation in the JRC data). The two data sets are less likely to detect the same disturbance when it is followed by a rapid recovery (such as short-duration degradation in the JRC data, including disturbances like drought, selective logging or low-intensity fires, which may only be detected in as few as one Landsat image) or disturbances resulting in gradual reduction of tree cover over a longer time period (such as degradation followed by deforestation in the JRC data). In these cases, the disturbance may not meet the UMD definition of tree cover loss and therefore is less likely to be detected in the UMD data.</p>



<p>Both data sets have different strengths. The UMD data is global in scope, allowing for comparative analysis across regions due to global consistency in definitions and methods. Within the tropics, the UMD data includes broader coverage of forest types beyond tropical moist forests, including tropical dry forests.<a href="https://gfw.global/3GEmSQh"></a> The UMD data also provides flexibility for users to adjust the canopy density threshold according to their preference or needs, which can be used to align with a specific forest definition or forest characteristics of a specific biome.</p>



<p>Meanwhile, the JRC data detects degradation and less intense disturbances, which can be helpful for users who want to understand where forests have experienced various types of stresses that have not resulted in complete loss. The JRC data also monitors forests after initial disturbances to track forest recovery and subsequent disturbances, which is helpful for users who would like to understand yearly change dynamics and identify where there are repeated disturbances.</p>



<p>However, it is important to note that we are not evaluating the accuracy of either data set. Assessing which data set is more accurate for a specific use case or geography would require a formal validation exercise.</p>



<p>Ultimately, these two data sets present complementary information that can help us better understand the various types of changes occurring in tropical forests.</p>



<hr> 

<div class="attribute" style="”padding-bottom:" 10px;”="">
 

Note: This blog investigates the JRC TMF map, which is a separate product from the JRC global map of forest cover for year 2020, released on December 7, 2023.

 

</div> 

 

<hr>



<style type="text/css"></style>

Differences Between Global Forest Watch’s Tree Cover Loss Data and JRC’s Tropical Moist Forest Data Explained

<p>The wide availability of forest and land cover maps based on satellite data provides more information on the world’s forests than ever before. However, this plethora of information can also be challenging for people trying to understand differences in data sources and decide which data to use for a specific purpose.</p>



<p>In the past, we’ve compared the <a href="https://gfw.global/3BfwQWz">annual tree cover loss data</a> from the University of Maryland (UMD) and available on Global Forest Watch (GFW) with national data from <a href="https://www.globalforestwatch.org/blog/data-and-research/2022-tree-cover-loss-data-explained/">Brazil and Indonesia</a>, as well as with data from the United Nations Food and Agriculture Organization’s (FAO) <a href="https://www.globalforestwatch.org/blog/data-and-research/global-forest-watch-and-the-forest-resources-assessment-explained-in-5-graphics-2/">Global Forest Resources Assessment</a>, to shed light on some of these differences.</p>



<p>Another data set that tracks forest change in the tropics is the <a href="https://forobs.jrc.ec.europa.eu/TMF" target="_blank" rel="noreferrer noopener">Tropical Moist Forest (TMF) data set</a> from the European Commission Joint Research Centre (JRC). Like the UMD tree cover loss data, the JRC TMF data is based on Landsat satellite imagery and is updated annually. Yet while both data sets map forest disturbances, the maps and numbers look a little different.</p>



<p>In this blog, we explain some key differences in the definitions and methods used for each data set that impact the resulting maps and discuss how the disturbances mapped by both data sets compare (while the data sets also map forest gain or regrowth, this blog focuses on comparing their mapping of forest disturbances). While understanding these differences can help determine the contexts for which each data set might be useful, note that this analysis does not evaluate the quality or accuracy of either data set.</p>



<h2 class="wp-block-heading">What areas do the JRC and UMD data sets cover, and how do they define forests?</h2>



<p>The UMD data set maps forests globally based on <a href="https://www.science.org/doi/10.1126/science.1244693" target="_blank" rel="noreferrer noopener">tree cover extent</a> in 2000. <a href="https://www.science.org/doi/10.1126/science.1244693" target="_blank" rel="noreferrer noopener">Tree cover</a> is defined as woody vegetation with a minimum height of at least five meters at 30-meter resolution, which includes all types of tree cover — including natural or managed forest and plantations — and is not limited to a specific forest type. The GFW map shows tree cover with a 30% canopy density, which we use in our analyses and in this comparison, although users can adjust the threshold based on their needs.</p>



<p>The JRC data set, on the other hand, <a href="https://www.science.org/doi/10.1126/sciadv.abe1603" target="_blank" rel="noreferrer noopener">maps forests</a> beginning in 1990. The data includes all closed primary and secondary forests in the humid tropics and does not apply a minimum height or canopy density threshold to delineate forest extent.</p>



<p>As a result of these definitional differences, some areas included in the 2000 UMD tree cover extent in the tropics like dry forests, young secondary forests and plantations are not classified as forests in the JRC data set in 2000 — a total of 655 million hectares (Mha), or 34%, of the UMD tree cover extent area that overlaps with the JRC data. Likewise, the JRC forest extent in 2000 includes some areas that do not meet the height and 30% canopy density threshold in the UMD data or are otherwise not mapped as tree cover by the UMD data — 17.2 Mha, or 1% of the JRC forest extent.</p>



<p>Because of the differences in geographic coverage and scope between the two data sets, this blog only compares forest disturbances from 2001-2022 for areas that, in the year 2000, are mapped both as tree cover by UMD and as forest by JRC.</p>



<h2 class="wp-block-heading">What types of forest disturbances do the UMD and JRC data map?</h2>



<h3 class="wp-block-heading"><em>The JRC Tropical Moist Forest data set maps degradation and deforestation in the humid tropics</em></h3>



<p>The JRC TMF data set maps disturbances to tropical moist forests — including degradation and deforestation — from 1990 to 2022. The JRC team maps these changes using an algorithm that detects forest disruptions, meaning an absence of tree foliage cover within a 30-meter pixel for each available Landsat image, and then classifies the status of forest based on how long these disruptions are visible.</p>



<p>The TMF data set <a href="https://www.science.org/doi/10.1126/sciadv.abe1603" target="_blank" rel="noreferrer noopener">defines degradation</a> as temporary disturbances occurring for up to 2.5 years, while it defines deforestation as longer-term disturbances where disruptions to tree cover are visible for more than 2.5 years and no tree regrowth is detected over the last three years. In any given year, a forest is considered disturbed if there is a disruption detected in at least one Landsat image during that year.</p>



<p>Thus, pixels classified as degraded are still considered forest, with existing or regrowing trees, while pixels classified as deforested are undergoing a longer-term loss of forest. Because disruptions are recorded and analyzed for the entire time series, the data set classifies dynamics over time; for example, a forest pixel may be classified as degraded in one year after a short-term disturbance, then after a period of recovery may later be classified as deforested after ongoing disturbances with no tree regrowth. The JRC deforestation class therefore includes direct deforestation (deforestation of undisturbed forest) or deforestation after degradation (deforestation of forest that was previously classified as degraded).</p>



<p>The data set also analyzes the frequency, duration of disruptions and time of forest recovery in between disruption events to identify deforestation following degradation versus multiple degradation events.</p>



<h3 class="wp-block-heading"><em>The UMD tree cover loss data set on GFW maps all types of tree cover loss globally</em></h3>



<p>The UMD tree cover loss data set maps annual tree cover loss from 2001 to 2022. The UMD team uses an algorithm that detects loss using change detection metrics based on comparison of Landsat images between the present and past years. Tree cover loss, <a href="https://www.science.org/doi/10.1126/science.1244693" target="_blank" rel="noreferrer noopener">defined as</a> a clearing of tree cover of at least a half of a 30-meter Landsat pixel, includes both temporary and permanent losses without defining or differentiating which loss is considered degradation or deforestation. Once classified as loss, pixels are masked from further updates, meaning that any following forest change dynamics — such as regrowth or subsequent disturbances — are not recorded.</p>



<p>The UMD tree cover loss data can be combined with contextual data layers, such as <a href="https://gfw.global/3kqcoqa">UMD’s map of humid tropical primary forest</a>, to see loss within specific forest types.</p>



<h4 class="wp-block-heading">Key differences between the JRC TMF and UMD tree cover loss data</h4>



<table border="1" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td style="width:165px;height:20px;">
			<p>&nbsp;</p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>JRC TMF</strong></p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>UMD tree cover loss</strong></p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Temporal coverage</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>1990-2022</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>&nbsp;2000-2022</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Geographic coverage and extent</p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>Tropical moist forest:</strong> closed primary and secondary forests in the humid tropics in 1990.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p><strong>Global tree cover: </strong>woody vegetation with a minimum height of at least five meters at 30-meter resolution in 2000.</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Definition of disturbance</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>An absence of tree foliage cover within a 30-meter pixel.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Clearing of at least half of tree cover within a 30-meter pixel.</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Disturbance classes</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Disturbances are classified as <strong>degradation </strong>if they are visible for less than 2.5 years, and <strong>deforestation </strong>if they are visible for more than 2.5 years with no vegetative regrowth over the last three years.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>All disturbances classified as <strong>tree cover loss. </strong>The length of disturbance is not considered.</p>
			</td>
		</tr>
		<tr>
			<td style="width:165px;height:20px;">
			<p>Methods</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Classifies valid single-date Landsat images and derives disturbance classes by analyzing the single-date classifications. Dynamics of disturbance events over time are recorded.</p>
			</td>
			<td style="width:320px;height:20px;">
			<p>Classifies change using change detection metrics derived from all valid Landsat images over the present and past years. Only the first loss event that is detected is recorded.</p>
			</td>
		</tr>
	</tbody>
</table>



<h2 class="wp-block-heading">What do the UMD and JRC data show about forest disturbances in the tropics?</h2>



<p>Overall, the JRC data detects a larger area of disturbances across the tropics from 2001-2022 compared with the UMD data. The JRC data detects 258 Mha of disturbances, including 113 Mha of degradation and 145 Mha of deforestation, while the UMD data detects 143 Mha of tree cover loss. However, trends in total deforestation mapped by JRC and tree cover loss mapped by UMD are generally aligned: They are largely similar for the first decade; then from 2013-2015, JRC detects a larger area as deforestation than UMD detects as loss, and after 2016, UMD detects a larger area.</p>



<div class="flourish-embed" data-src="story/2112582?163031"><script src="https://public.flourish.studio/resources/embed.js"></script></div>



<p>We further separated out the disturbance types mapped by the JRC data and overlaid the data sets to evaluate how the two data sets compare at each pixel.</p>



<p>Among all the JRC data’s disturbance classes, the JRC direct deforestation class aligned most closely with UMD tree cover loss. Across the tropics from 2001-2022, 46.8 Mha, or 68%, of the area classified as direct deforestation by the JRC data was also classified as tree cover loss in the UMD data. This varied by region and was highest in Asia/Oceania and the Americas (66% and 75% respectively) and lowest in Africa (50%). The UMD data less often classified areas that JRC identified as deforestation after degradation as tree cover loss (38.1 Mha, or 50% across the tropics).</p>



<p>In some areas, disturbances classified as degradation by the JRC TMF data set were classified as tree cover loss by the UMD data. Across the tropics from 2001-2022, 32.6 Mha, or 29%, of the area the JRC data classified as degradation was also classified as tree cover loss in the UMD data. The JRC degradation class includes three types of degradation: short-duration (less than one year), long-duration (1-2.5 years) and short-duration over 2-3 periods (short-duration degradation that occurs two to three separate times throughout the time period). The JRC data also measures “intensity” of degradation based on the total number of Landsat images where disruptions in tree cover were visible. We found that, in general, the UMD data:</p>



<ul>
<li>More often detected longer duration degradation as tree cover loss. Short-duration degradation (including events occurring just once or over 2-3 periods), which represents 85% of the forest area mapped as degraded by JRC since 2001, is usually not shown as tree cover loss by the UMD data.</li>



<li>Classified degradation events as tree cover loss that had an intensity of greater than six images on average, while those UMD did not classify as loss had approximately three images or less on average.</li>



<li>Detected a larger proportion of the area JRC classified as degradation from 2015 onwards, which may be <a href="https://www.globalforestwatch.org/blog/data-and-research/tree-cover-loss-satellite-data-trend-analysis/">due to the algorithm changes</a> in the UMD data that increase forest loss detection sensitivity in case of fires, selective logging and other disturbance types that JRC classified as degradation.</li>
</ul>



<p>In other areas across the tropics, the UMD data detected tree cover loss for 6.4 Mha, or 7%, of areas where there the JRC data detected no disturbance events.</p>



<figure class="wp-block-image size-full is-resized"><img src="https://content.globalforestwatch.org/wp-content/uploads/2024/01/Comparison-JRC-TMF-and-UMD-table.png" alt="Comparison of JRC TMF and UMD tree cover loss disturbances across the tropics" class="wp-image-16572" style="aspect-ratio:1.0507308684436802;width:771px;height:auto"/></figure>



<h4 class="wp-block-heading">Forest disturbances related to shifting cultivation in Mongala, DRC</h4>



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<h4 class="wp-block-heading">Large scale deforestation along BR-230 in Amazonas, Brazil</h4>



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<h4 class="wp-block-heading">Selective logging in Pará, Brazil</h4>



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<h2 class="wp-block-heading">Why does the UMD and JRC data align in some ways and differ in others?</h2>



<p>The two data sets align more closely for more abrupt disturbances that are likely to meet the definitions used in both data sets, such as intense fires (which the JRC data may classify as long-duration degradation) or clearance of tree cover for agricultural expansion (usually classified as deforestation in the JRC data). The two data sets are less likely to detect the same disturbance when it is followed by a rapid recovery (such as short-duration degradation in the JRC data, including disturbances like drought, selective logging or low-intensity fires, which may only be detected in as few as one Landsat image) or disturbances resulting in gradual reduction of tree cover over a longer time period (such as degradation followed by deforestation in the JRC data). In these cases, the disturbance may not meet the UMD definition of tree cover loss and therefore is less likely to be detected in the UMD data.</p>



<p>Both data sets have different strengths. The UMD data is global in scope, allowing for comparative analysis across regions due to global consistency in definitions and methods. Within the tropics, the UMD data includes broader coverage of forest types beyond tropical moist forests, including tropical dry forests.<a href="https://gfw.global/3GEmSQh"></a> The UMD data also provides flexibility for users to adjust the canopy density threshold according to their preference or needs, which can be used to align with a specific forest definition or forest characteristics of a specific biome.</p>



<p>Meanwhile, the JRC data detects degradation and less intense disturbances, which can be helpful for users who want to understand where forests have experienced various types of stresses that have not resulted in complete loss. The JRC data also monitors forests after initial disturbances to track forest recovery and subsequent disturbances, which is helpful for users who would like to understand yearly change dynamics and identify where there are repeated disturbances.</p>



<p>However, it is important to note that we are not evaluating the accuracy of either data set. Assessing which data set is more accurate for a specific use case or geography would require a formal validation exercise.</p>



<p>Ultimately, these two data sets present complementary information that can help us better understand the various types of changes occurring in tropical forests.</p>



<hr> 

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Note: This blog investigates the JRC TMF map, which is a separate product from the JRC global map of forest cover for year 2020, released on December 7, 2023.

 

</div> 

 

<hr>

We explain key differences between two data sets that track forest change in the tropics: UMD tree cover loss and JRC Tropical Moist Forest.

Tree Cover Loss and Tropical Moist Forest Differences, Explained

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<p><span class="NormalTextRun SCXW250124087 BCX0"><em>Susan Minnemayer and Lars Laestadius contributed to a previous version of this article.&nbsp;</em></span></p>



<p><a href="https://intactforests.org/" target="_blank" rel="noreferrer noopener">Intact forest landscapes</a>, or vast stretches of unbroken forested wilderness, are some of the most important ecosystems in the world. Their intactness makes them uniquely valuable to nature. They regulate temperature and rainfall across continents, provide homes to Indigenous Peoples, have some of the highest biodiversity rates in the world and store huge amounts of carbon, among other benefits.&nbsp;&nbsp;</p>



<p>But they’re also under threat.&nbsp;&nbsp;</p>



<p>According to the <a href="https://www.globalforestwatch.org/map/?map=eyJjZW50ZXIiOnsibGF0IjoyNS40MjMwMTc4NTYyMDY5NjUsImxuZyI6LTUxLjEwNTQ2ODc0OTk5OTUyNH0sImRhdGFzZXRzIjpbeyJkYXRhc2V0IjoiaW50YWN0LWZvcmVzdC1sYW5kc2NhcGVzIiwib3BhY2l0eSI6MSwidmlzaWJpbGl0eSI6dHJ1ZSwibGF5ZXJzIjpbImludGFjdC1mb3Jlc3QtbGFuZHNjYXBlcyJdfSx7ImRhdGFzZXQiOiJwb2xpdGljYWwtYm91bmRhcmllcyIsImxheWVycyI6WyJkaXNwdXRlZC1wb2xpdGljYWwtYm91bmRhcmllcyIsInBvbGl0aWNhbC1ib3VuZGFyaWVzIl0sIm9wYWNpdHkiOjEsInZpc2liaWxpdHkiOnRydWV9XX0%3D&mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D">latest data on Global Forest Watch</a>, the extent of world’s intact forest landscapes decreased by 12% (155 million hectares) between 2000 and 2020. This is an area larger than twice the size of Chile.&nbsp;&nbsp;</p>



<p>Furthermore, the global rate at which intact forest landscapes are decreasing is speeding up, from an average of 7.1 million hectares per year from 2000-2013 to an average of 9 million hectares per year from 2013-2020.&nbsp;</p>



<p>New roads developed for industrial timber and oil and gas extraction, agricultural expansion and fires<sup>1</sup> are the <a href="https://www.science.org/doi/10.1126/sciadv.1600821" target="_blank" rel="noreferrer noopener">main causes</a> of reduction in the extent of intact forest landscapes. If the trend doesn’t reverse, the world could lose much of its unbroken forest tracts this century, posing problems for nature, the climate and human well-being.&nbsp;</p>



<aside id="textbox"> <div><em><b>How are intact forest landscapes defined?</b><p></p> 

Intact forest landscapes are patches of forests and natural treeless ecosystems that show no signs of significant human activity or habitat fragmentation (as detected by satellite imagery) and are large enough to maintain all native biodiversity. Some forms of low-intensity or historic human disturbances, such as scattered, small-scale shifting cultivation and low-intensity selective logging may be included in an intact forest landscape if the disturbance is too small to be detected by satellites.  <br><br>
In order to ensure that areas designated as intact forest landscapes are large enough to provide refuge for wide-ranging species, researchers used <a href="https://intactforests.org/method.html" target="_blank" rel="noopener noreferrer">three criteria</a> in addition to the requirement of no visible, significant human-caused disturbances: 1) minimum area of 50,000 hectares; 2) minimum patch width of 10 km; and 3) minimum corridor/appendage width of 2 km.  
<br><br>
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A portion of an intact forest landscape, or in some cases an entire patch, may no longer be considered an intact forest landscape if these criteria are no longer met due to human-caused alteration or fragmentation. For example, if a road is built across an intact forest landscape patch that causes the remaining patches to no longer meet the criteria, the entire patch would no longer be considered an intact forest landscape. As a result, that intact forest landscape area is lost and the total global area decreases. For each update of the global intact forest landscape map, researchers only assess areas currently designated as intact forest landscapes. Therefore, this methodology does not take into account forest regeneration and assumes that once lost, intactness cannot be regained. </em></div> </aside>



<h2 class="wp-block-heading">Where and Why Are Intact Forests Becoming Fragmented?&nbsp;</h2>



<p>Countries with the largest remaining areas of intact forest landscapes are found primarily in boreal and tropical regions. These areas also experienced the largest reduction in intact forest landscape area over the past two decades. Only small areas of intact forest landscapes remain in temperate regions due to extensive commercial logging and agricultural activities prior to the year 2000.&nbsp;&nbsp;</p>



<p>Timber harvesting and agricultural expansion were the leading drivers of reduction of intact forest landscapes in the tropics, while timber harvesting was the leading cause in the southern boreal and temperate zones. In the northern boreal region, human-caused fires were the leading driver of intact forest landscape reduction.&nbsp;</p>



<p>As of 2020, Canada, Russia and Brazil had the largest area of remaining intact forest landscapes, making up over 65% of the global total. However, these countries also experienced the largest reduction from 2000-2020.&nbsp;&nbsp;</p>



<p>Russia experienced the largest reduction in intact forest landscape area between 2000 to 2020, losing 40.9 million hectares due largely to oil and gas extraction, industrial logging, gold mining and extensive human-caused fires linked to these activities.&nbsp;&nbsp;</p>



<p>In Brazil, which experienced the second-highest reduction, agricultural and pasture expansion was responsible. In Canada, human-caused fires adjacent to logging, mining and infrastructure were the leading driver.&nbsp;&nbsp;</p>



<p>Romania had the largest percent decline, losing all of its intact forest landscape area by 2013, followed by Paraguay, where the intact forest landscape area decreased by 81% by 2020. The Solomon Islands, Laos, Central African Republic, Nicaragua and Equatorial Guinea lost over half of their intact forest landscape area by 2020.&nbsp;&nbsp;</p>



<p>However, not all countries experienced a decline in intact forest landscape extent. Although they contain a relatively small area, Cuba and Japan had almost no change in their extent of intact forest landscapes from 2000-2020.&nbsp;&nbsp;</p>



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<h2 class="wp-block-heading">The Problem with Losing Forest Intactness&nbsp;</h2>



<aside id="textbox"> <div><em><b>Multiple measures of forest health</b><p></p> 

Various methodologies exist for designating forests that have significant ecological value. These include <a href="https://www.hcvnetwork.org/hcv-approach" target="_blank" rel="noopener noreferrer">High Conservation Value (HCV) Forests</a>, <a href="https://highcarbonstock.org/" target="_blank" rel="noopener noreferrer">High Carbon Stock Forests</a> and <a href="https://www.globalforestwatch.org/map/?map=eyJkYXRhc2V0cyI6W3siZGF0YXNldCI6ImZvcmVzdC1sYW5kc2NhcGUtaW50ZWdyaXR5LWluZGV4Iiwib3BhY2l0eSI6MSwidmlzaWJpbGl0eSI6dHJ1ZSwibGF5ZXJzIjpbImZvcmVzdC1sYW5kc2NhcGUtaW50ZWdyaXR5LWluZGV4LTIwMjEiXX0seyJkYXRhc2V0IjoicG9saXRpY2FsLWJvdW5kYXJpZXMiLCJsYXllcnMiOlsiZGlzcHV0ZWQtcG9saXRpY2FsLWJvdW5kYXJpZXMiLCJwb2xpdGljYWwtYm91bmRhcmllcyJdLCJvcGFjaXR5IjoxLCJ2aXNpYmlsaXR5Ijp0cnVlfV19&mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D" target="_blank" rel="noopener noreferrer">Forest Landscape Integrity</a>, in addition to intact forest landscapes. Although these designations can all be used to identify forests that are important to protect, they differ with respect to their specific definitions, requirements and methodologies, and they each have strengths and limitations depending on the context and purpose for which they are used. <br><br>
In some cases, these measures can be complementary. For example, the <a href="https://www.wri.org/insights/why-preserving-forest-integrity-preventing-deforestation" target="_blank" rel="noopener noreferrer">Forest Landscape Integrity Index</a> measures the degree to which a forest’s structure, composition and function are free from modification by humans, and can show forest degradation on a spectrum. This can provide information about the variation in integrity outside the most intact areas. Meanwhile, intact forest landscapes are a binary classification, and the forests found within them have high integrity values.  

</em></div> </aside>



<p>Intact forest landscapes are unique and irreplaceable. With many forests around the world being degraded and lost, intact forest landscapes offer important areas of high forest integrity. Intactness cannot easily be regained — once altered, complex assemblages of biodiversity would be extremely challenging to restore.&nbsp;&nbsp;</p>



<p>For example, extending new roads into remote forest areas facilitates human access, which can lead to cascading changes: wildlife habitat loss, unregulated hunting, increased human settlement and population density, forest clearing from logging, forest loss from agricultural expansion, fires, and other changes that degrade forests and may eventually convert vast forest areas to other land uses.&nbsp;&nbsp;</p>



<p>Intact forests also offer a unique opportunity to mitigate two of the greatest environmental challenges Earth faces: climate change and species extinction.&nbsp;&nbsp;</p>



<p>Intact forest landscapes are critical for sequestering and storing carbon. Forests within remaining intact forest landscapes had an average annual net sink of -2 gigatonnes CO2e per year from 2001-2021, making up <a href="https://www.nature.com/articles/s41558-020-00976-6" target="_blank" rel="noreferrer noopener">over one-quarter</a> of the average annual global net carbon sink from forests. On average, tropical intact forests <a href="https://www.science.org/doi/10.1126/sciadv.1600821" target="_blank" rel="noreferrer noopener">store triple the amount</a> of above-ground carbon of non-intact tropical forests.&nbsp;&nbsp;</p>



<p>Meanwhile, northern boreal forests have huge soil carbon stores. While they store less above-ground carbon than their tropical counterparts, boreal intact forests occupy a vast area, making up 38% of global intact forest landscapes in 2020. These intact forest landscapes <a href="https://www.globalforestwatch.org/blog/climate/intact-forest-landscapes-matter-for-climate-change-here-are-3-reasons-why/?utm_campaign=gfw&utm_source=gfwblog&utm_medium=hyperlink&utm_term=borealfires_10_2019" target="_blank" rel="noreferrer noopener">play an important role in the protection of permafrost</a>, which is critical to preventing the release of climate-warming carbon and methane locked in soils.&nbsp;&nbsp;</p>



<p>Additionally, scientists estimate that tropical forests contain <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2420" target="_blank" rel="noreferrer noopener">over half of the world’s terrestrial vertebrate species</a>, despite occupying less than one-fifth of global land area. Many of these species depend on intact forests for their survival.&nbsp;&nbsp;</p>



<h2 class="wp-block-heading">How Can We Protect Intact Forest Landscapes? &nbsp;</h2>



<p>The importance of intact forest landscapes is being increasingly recognized in conservation and climate policy. The International Union for the Conservation of Nature (IUCN), for example, <a href="https://www.iucn.org/resources/policy-statement/iucn-policy-statement-primary-forests-including-intact-forest-landscapes" target="_blank" rel="noreferrer noopener">recognizes the value of intact forest landscapes and the need to conserve them</a> in their <a href="https://www.iucn.org/resources/policy-statement/iucn-policy-statement-primary-forests-including-intact-forest-landscapes" target="_blank" rel="noreferrer noopener">policy on primary forests</a>, recommending that stakeholders take steps to mitigate threats to intact forests and identify appropriate management options. IUCN policies, which are adopted through multi-stakeholder processes among IUCN member organizations including civil society and governments, guide global conservation priorities. This recognition can help elevate the importance of intact forest landscapes in national and international policy.&nbsp;&nbsp;</p>



<p>Additionally, climate finance is becoming more accessible to countries with large areas of intact forest and low deforestation rates, such as through crediting for the protection of forests in these jurisdictions as part of the <a href="https://www.artredd.org/trees/" target="_blank" rel="noreferrer noopener">Architecture for REDD+ Transactions (ART) Environmental Excellence Standard</a>. Increasing flows of climate finance can support countries in their efforts to preserve intact forests.&nbsp;&nbsp;</p>



<p>For international agreements and national forest commitments that aim to halt forest loss — including the <a href="https://forestdeclaration.org/about/new-york-declaration-on-forests/" target="_blank" rel="noreferrer noopener">New York Declaration on Forests</a>, the <a href="https://sdgs.un.org/goals" target="_blank" rel="noreferrer noopener">UN Sustainable Development Goals</a>, the <a href="https://ukcop26.org/glasgow-leaders-declaration-on-forests-and-land-use/" target="_blank" rel="noreferrer noopener">Glasgow Leaders Declaration on Forests and Land Use</a> and the <a href="https://www.cbd.int/conferences/post2020" target="_blank" rel="noreferrer noopener">Convention on Biological Diversity’s (CBD) Post-2020 Biodiversity Framework</a> — intact forest landscapes offer a measurable benchmark toward goals. They are also important areas to prioritize in order to achieve many of these international targets.&nbsp;</p>



<p><a href="https://www.science.org/doi/10.1126/sciadv.1600821" target="_blank" rel="noreferrer noopener">Research shows</a> that designating intact forest landscapes as protected areas has proven effective at limiting their fragmentation, but only <a href="https://research.wri.org/gfr/forest-designation-indicators/protected-forests" target="_blank" rel="noreferrer noopener">36% of remaining intact forests are under some form of legal protection</a>. Countries should consider intact forest landscapes high-priority candidates when they revise or expand existing protected areas, such as through efforts to meet the CBD’s Post-2020 Biodiversity Framework target to conserve and equitably manage 30% of global land by 2030.&nbsp;&nbsp;</p>



<p>Moreover, <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2148" target="_blank" rel="noreferrer noopener">research shows</a> that the rate of intact forest loss is lower in areas that overlap with Indigenous Peoples’ lands — over one-third of intact forest landscapes globally — highlighting local communities’ critical role in managing these forests. Recognizing Indigenous Peoples’ land tenure rights and supporting their efforts to sustainably manage their lands can help avoid further fragmentation of intact forest landscapes.&nbsp;&nbsp;</p>



<p></p>



<p><em><sup>1</sup> Fire-related disturbances are considered a factor that can lead to a reduction in intact forest landscape area only when they are likely to be caused by humans, rather than natural causes (such as lightning strikes). The intact forest landscape methodology differentiates natural fires from human-caused fires by assuming that burned areas that are adjacent to areas with human access (e.g.,&nbsp;near infrastructure, logging sites or agricultural areas) are likely to be caused by humans.&nbsp;</em></p>



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<div class="attribute">The latest intact forest landscape boundaries are now available on <a href="https://www.globalforestwatch.org/map/?map=eyJjZW50ZXIiOnsibGF0IjoyNS40MjMwMTc4NTYyMDY5NjUsImxuZyI6LTUxLjEwNTQ2ODc0OTk5OTUyNH0sImRhdGFzZXRzIjpbeyJkYXRhc2V0IjoiaW50YWN0LWZvcmVzdC1sYW5kc2NhcGVzIiwib3BhY2l0eSI6MSwidmlzaWJpbGl0eSI6dHJ1ZSwibGF5ZXJzIjpbImludGFjdC1mb3Jlc3QtbGFuZHNjYXBlcyJdfSx7ImRhdGFzZXQiOiJwb2xpdGljYWwtYm91bmRhcmllcyIsImxheWVycyI6WyJkaXNwdXRlZC1wb2xpdGljYWwtYm91bmRhcmllcyIsInBvbGl0aWNhbC1ib3VuZGFyaWVzIl0sIm9wYWNpdHkiOjEsInZpc2liaWxpdHkiOnRydWV9XX0%3D&mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D" target="_blank" rel="noopener noreferrer">Global Forest Watch</a>, along with tools and data to monitor how forest change is affecting them.<br><br>  

The authors would like to acknowledge members of the IFL mapping team who contributed to the intact forest landscape data update, including Svetlana Turubanova (University of Maryland), and Anna Komarova, Igor Glushkov and Ilona Zhuravleva (Greenpeace).</div>

<div class="attribute">This post originally appeared on <a href="https://www.wri.org/insights/worlds-last-intact-forests-are-becoming-increasingly-fragmented-0" target="_blank" rel="noopener noreferrer">Insights</a>.</div>



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The World’s Last Intact Forests Are Becoming Increasingly Fragmented

<p><span class="NormalTextRun SCXW250124087 BCX0"><em>Susan Minnemayer and Lars Laestadius contributed to a previous version of this article.&nbsp;</em></span></p>



<p><a href="https://intactforests.org/" target="_blank" rel="noreferrer noopener">Intact forest landscapes</a>, or vast stretches of unbroken forested wilderness, are some of the most important ecosystems in the world. Their intactness makes them uniquely valuable to nature. They regulate temperature and rainfall across continents, provide homes to Indigenous Peoples, have some of the highest biodiversity rates in the world and store huge amounts of carbon, among other benefits.&nbsp;&nbsp;</p>



<p>But they’re also under threat.&nbsp;&nbsp;</p>



<p>According to the <a href="https://www.globalforestwatch.org/map/?map=eyJjZW50ZXIiOnsibGF0IjoyNS40MjMwMTc4NTYyMDY5NjUsImxuZyI6LTUxLjEwNTQ2ODc0OTk5OTUyNH0sImRhdGFzZXRzIjpbeyJkYXRhc2V0IjoiaW50YWN0LWZvcmVzdC1sYW5kc2NhcGVzIiwib3BhY2l0eSI6MSwidmlzaWJpbGl0eSI6dHJ1ZSwibGF5ZXJzIjpbImludGFjdC1mb3Jlc3QtbGFuZHNjYXBlcyJdfSx7ImRhdGFzZXQiOiJwb2xpdGljYWwtYm91bmRhcmllcyIsImxheWVycyI6WyJkaXNwdXRlZC1wb2xpdGljYWwtYm91bmRhcmllcyIsInBvbGl0aWNhbC1ib3VuZGFyaWVzIl0sIm9wYWNpdHkiOjEsInZpc2liaWxpdHkiOnRydWV9XX0%3D&amp;mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D">latest data on Global Forest Watch</a>, the extent of world’s intact forest landscapes decreased by 12% (155 million hectares) between 2000 and 2020. This is an area larger than twice the size of Chile.&nbsp;&nbsp;</p>



<p>Furthermore, the global rate at which intact forest landscapes are decreasing is speeding up, from an average of 7.1 million hectares per year from 2000-2013 to an average of 9 million hectares per year from 2013-2020.&nbsp;</p>



<p>New roads developed for industrial timber and oil and gas extraction, agricultural expansion and fires<sup>1</sup> are the <a href="https://www.science.org/doi/10.1126/sciadv.1600821" target="_blank" rel="noreferrer noopener">main causes</a> of reduction in the extent of intact forest landscapes. If the trend doesn’t reverse, the world could lose much of its unbroken forest tracts this century, posing problems for nature, the climate and human well-being.&nbsp;</p>



<aside id="textbox"> <div><em><b>How are intact forest landscapes defined?</b><p></p> 

Intact forest landscapes are patches of forests and natural treeless ecosystems that show no signs of significant human activity or habitat fragmentation (as detected by satellite imagery) and are large enough to maintain all native biodiversity. Some forms of low-intensity or historic human disturbances, such as scattered, small-scale shifting cultivation and low-intensity selective logging may be included in an intact forest landscape if the disturbance is too small to be detected by satellites.  <br><br>
In order to ensure that areas designated as intact forest landscapes are large enough to provide refuge for wide-ranging species, researchers used <a href="https://intactforests.org/method.html" target="_blank" rel="noopener noreferrer">three criteria</a> in addition to the requirement of no visible, significant human-caused disturbances: 1) minimum area of 50,000 hectares; 2) minimum patch width of 10 km; and 3) minimum corridor/appendage width of 2 km.  
<br><br>
<img class=" wp-image-3569 alignright" style="padding-bottom: 10px;" src="https://content.globalforestwatch.org/wp-content/uploads/2022/11/22.10.27_Definition-of-IFL_Insights-3.png" width="100%">

A portion of an intact forest landscape, or in some cases an entire patch, may no longer be considered an intact forest landscape if these criteria are no longer met due to human-caused alteration or fragmentation. For example, if a road is built across an intact forest landscape patch that causes the remaining patches to no longer meet the criteria, the entire patch would no longer be considered an intact forest landscape. As a result, that intact forest landscape area is lost and the total global area decreases. For each update of the global intact forest landscape map, researchers only assess areas currently designated as intact forest landscapes. Therefore, this methodology does not take into account forest regeneration and assumes that once lost, intactness cannot be regained. </em></div> </aside>



<h2 class="wp-block-heading">Where and Why Are Intact Forests Becoming Fragmented?&nbsp;</h2>



<p>Countries with the largest remaining areas of intact forest landscapes are found primarily in boreal and tropical regions. These areas also experienced the largest reduction in intact forest landscape area over the past two decades. Only small areas of intact forest landscapes remain in temperate regions due to extensive commercial logging and agricultural activities prior to the year 2000.&nbsp;&nbsp;</p>



<p>Timber harvesting and agricultural expansion were the leading drivers of reduction of intact forest landscapes in the tropics, while timber harvesting was the leading cause in the southern boreal and temperate zones. In the northern boreal region, human-caused fires were the leading driver of intact forest landscape reduction.&nbsp;</p>



<p>As of 2020, Canada, Russia and Brazil had the largest area of remaining intact forest landscapes, making up over 65% of the global total. However, these countries also experienced the largest reduction from 2000-2020.&nbsp;&nbsp;</p>



<p>Russia experienced the largest reduction in intact forest landscape area between 2000 to 2020, losing 40.9 million hectares due largely to oil and gas extraction, industrial logging, gold mining and extensive human-caused fires linked to these activities.&nbsp;&nbsp;</p>



<p>In Brazil, which experienced the second-highest reduction, agricultural and pasture expansion was responsible. In Canada, human-caused fires adjacent to logging, mining and infrastructure were the leading driver.&nbsp;&nbsp;</p>



<p>Romania had the largest percent decline, losing all of its intact forest landscape area by 2013, followed by Paraguay, where the intact forest landscape area decreased by 81% by 2020. The Solomon Islands, Laos, Central African Republic, Nicaragua and Equatorial Guinea lost over half of their intact forest landscape area by 2020.&nbsp;&nbsp;</p>



<p>However, not all countries experienced a decline in intact forest landscape extent. Although they contain a relatively small area, Cuba and Japan had almost no change in their extent of intact forest landscapes from 2000-2020.&nbsp;&nbsp;</p>



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<h2 class="wp-block-heading">The Problem with Losing Forest Intactness&nbsp;</h2>



<aside id="textbox"> <div><em><b>Multiple measures of forest health</b><p></p> 

Various methodologies exist for designating forests that have significant ecological value. These include <a href="https://www.hcvnetwork.org/hcv-approach" target="_blank" rel="noopener noreferrer">High Conservation Value (HCV) Forests</a>, <a href="https://highcarbonstock.org/" target="_blank" rel="noopener noreferrer">High Carbon Stock Forests</a> and <a href="https://www.globalforestwatch.org/map/?map=eyJkYXRhc2V0cyI6W3siZGF0YXNldCI6ImZvcmVzdC1sYW5kc2NhcGUtaW50ZWdyaXR5LWluZGV4Iiwib3BhY2l0eSI6MSwidmlzaWJpbGl0eSI6dHJ1ZSwibGF5ZXJzIjpbImZvcmVzdC1sYW5kc2NhcGUtaW50ZWdyaXR5LWluZGV4LTIwMjEiXX0seyJkYXRhc2V0IjoicG9saXRpY2FsLWJvdW5kYXJpZXMiLCJsYXllcnMiOlsiZGlzcHV0ZWQtcG9saXRpY2FsLWJvdW5kYXJpZXMiLCJwb2xpdGljYWwtYm91bmRhcmllcyJdLCJvcGFjaXR5IjoxLCJ2aXNpYmlsaXR5Ijp0cnVlfV19&amp;mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D" target="_blank" rel="noopener noreferrer">Forest Landscape Integrity</a>, in addition to intact forest landscapes. Although these designations can all be used to identify forests that are important to protect, they differ with respect to their specific definitions, requirements and methodologies, and they each have strengths and limitations depending on the context and purpose for which they are used. <br><br>
In some cases, these measures can be complementary. For example, the <a href="https://www.wri.org/insights/why-preserving-forest-integrity-preventing-deforestation" target="_blank" rel="noopener noreferrer">Forest Landscape Integrity Index</a> measures the degree to which a forest’s structure, composition and function are free from modification by humans, and can show forest degradation on a spectrum. This can provide information about the variation in integrity outside the most intact areas. Meanwhile, intact forest landscapes are a binary classification, and the forests found within them have high integrity values.  

</em></div> </aside>



<p>Intact forest landscapes are unique and irreplaceable. With many forests around the world being degraded and lost, intact forest landscapes offer important areas of high forest integrity. Intactness cannot easily be regained — once altered, complex assemblages of biodiversity would be extremely challenging to restore.&nbsp;&nbsp;</p>



<p>For example, extending new roads into remote forest areas facilitates human access, which can lead to cascading changes: wildlife habitat loss, unregulated hunting, increased human settlement and population density, forest clearing from logging, forest loss from agricultural expansion, fires, and other changes that degrade forests and may eventually convert vast forest areas to other land uses.&nbsp;&nbsp;</p>



<p>Intact forests also offer a unique opportunity to mitigate two of the greatest environmental challenges Earth faces: climate change and species extinction.&nbsp;&nbsp;</p>



<p>Intact forest landscapes are critical for sequestering and storing carbon. Forests within remaining intact forest landscapes had an average annual net sink of -2 gigatonnes CO2e per year from 2001-2021, making up <a href="https://www.nature.com/articles/s41558-020-00976-6" target="_blank" rel="noreferrer noopener">over one-quarter</a> of the average annual global net carbon sink from forests. On average, tropical intact forests <a href="https://www.science.org/doi/10.1126/sciadv.1600821" target="_blank" rel="noreferrer noopener">store triple the amount</a> of above-ground carbon of non-intact tropical forests.&nbsp;&nbsp;</p>



<p>Meanwhile, northern boreal forests have huge soil carbon stores. While they store less above-ground carbon than their tropical counterparts, boreal intact forests occupy a vast area, making up 38% of global intact forest landscapes in 2020. These intact forest landscapes <a href="https://www.globalforestwatch.org/blog/climate/intact-forest-landscapes-matter-for-climate-change-here-are-3-reasons-why/?utm_campaign=gfw&amp;utm_source=gfwblog&amp;utm_medium=hyperlink&amp;utm_term=borealfires_10_2019" target="_blank" rel="noreferrer noopener">play an important role in the protection of permafrost</a>, which is critical to preventing the release of climate-warming carbon and methane locked in soils.&nbsp;&nbsp;</p>



<p>Additionally, scientists estimate that tropical forests contain <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2420" target="_blank" rel="noreferrer noopener">over half of the world’s terrestrial vertebrate species</a>, despite occupying less than one-fifth of global land area. Many of these species depend on intact forests for their survival.&nbsp;&nbsp;</p>



<h2 class="wp-block-heading">How Can We Protect Intact Forest Landscapes? &nbsp;</h2>



<p>The importance of intact forest landscapes is being increasingly recognized in conservation and climate policy. The International Union for the Conservation of Nature (IUCN), for example, <a href="https://www.iucn.org/resources/policy-statement/iucn-policy-statement-primary-forests-including-intact-forest-landscapes" target="_blank" rel="noreferrer noopener">recognizes the value of intact forest landscapes and the need to conserve them</a> in their <a href="https://www.iucn.org/resources/policy-statement/iucn-policy-statement-primary-forests-including-intact-forest-landscapes" target="_blank" rel="noreferrer noopener">policy on primary forests</a>, recommending that stakeholders take steps to mitigate threats to intact forests and identify appropriate management options. IUCN policies, which are adopted through multi-stakeholder processes among IUCN member organizations including civil society and governments, guide global conservation priorities. This recognition can help elevate the importance of intact forest landscapes in national and international policy.&nbsp;&nbsp;</p>



<p>Additionally, climate finance is becoming more accessible to countries with large areas of intact forest and low deforestation rates, such as through crediting for the protection of forests in these jurisdictions as part of the <a href="https://www.artredd.org/trees/" target="_blank" rel="noreferrer noopener">Architecture for REDD+ Transactions (ART) Environmental Excellence Standard</a>. Increasing flows of climate finance can support countries in their efforts to preserve intact forests.&nbsp;&nbsp;</p>



<p>For international agreements and national forest commitments that aim to halt forest loss — including the <a href="https://forestdeclaration.org/about/new-york-declaration-on-forests/" target="_blank" rel="noreferrer noopener">New York Declaration on Forests</a>, the <a href="https://sdgs.un.org/goals" target="_blank" rel="noreferrer noopener">UN Sustainable Development Goals</a>, the <a href="https://ukcop26.org/glasgow-leaders-declaration-on-forests-and-land-use/" target="_blank" rel="noreferrer noopener">Glasgow Leaders Declaration on Forests and Land Use</a> and the <a href="https://www.cbd.int/conferences/post2020" target="_blank" rel="noreferrer noopener">Convention on Biological Diversity’s (CBD) Post-2020 Biodiversity Framework</a> — intact forest landscapes offer a measurable benchmark toward goals. They are also important areas to prioritize in order to achieve many of these international targets.&nbsp;</p>



<p><a href="https://www.science.org/doi/10.1126/sciadv.1600821" target="_blank" rel="noreferrer noopener">Research shows</a> that designating intact forest landscapes as protected areas has proven effective at limiting their fragmentation, but only <a href="https://research.wri.org/gfr/forest-designation-indicators/protected-forests" target="_blank" rel="noreferrer noopener">36% of remaining intact forests are under some form of legal protection</a>. Countries should consider intact forest landscapes high-priority candidates when they revise or expand existing protected areas, such as through efforts to meet the CBD’s Post-2020 Biodiversity Framework target to conserve and equitably manage 30% of global land by 2030.&nbsp;&nbsp;</p>



<p>Moreover, <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/fee.2148" target="_blank" rel="noreferrer noopener">research shows</a> that the rate of intact forest loss is lower in areas that overlap with Indigenous Peoples’ lands — over one-third of intact forest landscapes globally — highlighting local communities’ critical role in managing these forests. Recognizing Indigenous Peoples’ land tenure rights and supporting their efforts to sustainably manage their lands can help avoid further fragmentation of intact forest landscapes.&nbsp;&nbsp;</p>



<p></p>



<p><em><sup>1</sup> Fire-related disturbances are considered a factor that can lead to a reduction in intact forest landscape area only when they are likely to be caused by humans, rather than natural causes (such as lightning strikes). The intact forest landscape methodology differentiates natural fires from human-caused fires by assuming that burned areas that are adjacent to areas with human access (e.g.,&nbsp;near infrastructure, logging sites or agricultural areas) are likely to be caused by humans.&nbsp;</em></p>



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<div class="attribute">The latest intact forest landscape boundaries are now available on <a href="https://www.globalforestwatch.org/map/?map=eyJjZW50ZXIiOnsibGF0IjoyNS40MjMwMTc4NTYyMDY5NjUsImxuZyI6LTUxLjEwNTQ2ODc0OTk5OTUyNH0sImRhdGFzZXRzIjpbeyJkYXRhc2V0IjoiaW50YWN0LWZvcmVzdC1sYW5kc2NhcGVzIiwib3BhY2l0eSI6MSwidmlzaWJpbGl0eSI6dHJ1ZSwibGF5ZXJzIjpbImludGFjdC1mb3Jlc3QtbGFuZHNjYXBlcyJdfSx7ImRhdGFzZXQiOiJwb2xpdGljYWwtYm91bmRhcmllcyIsImxheWVycyI6WyJkaXNwdXRlZC1wb2xpdGljYWwtYm91bmRhcmllcyIsInBvbGl0aWNhbC1ib3VuZGFyaWVzIl0sIm9wYWNpdHkiOjEsInZpc2liaWxpdHkiOnRydWV9XX0%3D&amp;mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D" target="_blank" rel="noopener noreferrer">Global Forest Watch</a>, along with tools and data to monitor how forest change is affecting them.<br><br>  

The authors would like to acknowledge members of the IFL mapping team who contributed to the intact forest landscape data update, including Svetlana Turubanova (University of Maryland), and Anna Komarova, Igor Glushkov and Ilona Zhuravleva (Greenpeace).</div>

<div class="attribute">This post originally appeared on <a href="https://www.wri.org/insights/worlds-last-intact-forests-are-becoming-increasingly-fragmented-0" target="_blank" rel="noopener noreferrer">Insights</a>.</div>



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Intact forest landscapes are some of the most important ecosystems in the world. But they decreased by 12% between 2000 and 2020.

The World’s Last Intact Forests Are Increasingly Fragmented | GFW

https://secure.gravatar.com/avatar/24e4b4a3160f1ef325f06a7df2da246f?s=96&d=mm&r=g

Octavia Payne

Logging roads in Papua province, Indonesia

Logging roads

Tom Evans

Hedley Grantham

Rod Taylor

<p>Most people point to deforestation — the clearing or burning of forests to make way for a different land-use, such as agriculture — as the greatest threat facing the world’s forests. But there’s another issue that’s just as important: forest integrity.&nbsp;</p>



<p>Forest integrity refers to the health of the forest that remains standing, including its ability to store carbon, protect biodiversity, and provide social and economic benefits. Though equally important, forest integrity is harder to measure than deforestation. </p>



<p>The Forest Landscape Integrity Index on <a href="https://gfw.global/3tKOYUP" target="_blank" rel="noreferrer noopener">Global Forest Watch </a>tracks forest integrity globally for the first time and shows that <strong>less than half of the world’s remaining forests have high integrity.&nbsp;&nbsp;</strong></p>



<p>Here, we explain what forest integrity is and examine the health of the world’s remaining forests.&nbsp;</p>



<h2 class="wp-block-heading">What is forest integrity?&nbsp;</h2>



<p>Forest integrity is defined by scientists as the degree to which a forest’s structure, composition and function are free from modification by humans. It exists as a spectrum, with very high-integrity forests on one end and very low-integrity, severely degraded forests on the other. </p>



<p>Minimal human influence is associated with high forest integrity; as more and more human activities affect a forest — such as logging, human-caused fires or farming — integrity declines. A high-integrity forest usually provides more environmental benefits than a forest of lower integrity. For example, high-integrity forests are generally more effective at: </p>



<ul>
<li>Slowing the pace of climate change by sequestering and storing carbon</li>



<li>Regulating water flows by stabilizing soils</li>



<li>Maintaining rainfall patterns through evapotranspiration</li>



<li>Providing habitat for forest-dependent animals</li>



<li>Supporting Indigenous Peoples’ and local communities’ livelihoods and cultural traditions</li>



<li><a href="https://sdg.iisd.org/commentary/guest-articles/preventing-future-pandemics-starts-with-protecting-our-forests/" target="_blank" rel="noreferrer noopener">Preventing future pandemics</a> by limiting the spread of zoonotic diseases. </li>
</ul>



<p>High-integrity forests are also typically more resilient to the impacts of climate change, such as the warmer, drier conditions that can lead to forest fires.&nbsp;</p>



<div class="imagecenter"><img decoding="async" class=" wp-image-3569 alignright" style="padding-bottom: 10px;" alt="How we measure forest integrity, how it degrades, and what happens when it is lost" src="https://content.globalforestwatch.org/wp-content/uploads/2022/04/22.03.23-Forest-integrity-v3_Formatted-for-Insights-1-2.png" width="100%"></div>



<h2 class="wp-block-heading">What are the biggest threats to forest integrity?&nbsp;&nbsp;</h2>



<p>Forests can be degraded directly by a wide range of human activities, including intensive logging, human-caused fires and over-hunting.&nbsp;&nbsp;</p>



<p>They can also be degraded in less visible ways by fragmentation, and by the “edge effects” that spill over from adjacent human activities such as infrastructure development, farming and urbanization. </p>



<p>A forest edge is more exposed and accessible than its interior, leaving it more susceptible to human activities like wood fuel extraction, hunting, livestock grazing, burning and the spread of invasive species, and more vulnerable to conditions such as direct sunlight, high winds, heatwaves and droughts. &nbsp;</p>



<aside id="textbox"> <div><em><b>How the Forest Landscape Integrity Index works </b><br><br>The Forest Landscape Integrity Index estimates the loss of integrity in a given area of forest by combining observed reductions in forest connectivity with proxy data on the intensity of human activities known to degrade forests. Some of these activities are observed directly as part of the analysis, specifically infrastructure, agriculture and recent deforestation. The associated edge effects cannot readily be observed, so they are estimated using models based on field studies.   
</em></div> </aside>



<h2 class="wp-block-heading">Where are the world’s remaining high-integrity forests?&nbsp;</h2>



<p>The Forest Landscape Integrity Index examines forest integrity along a spectrum and categorizes forests as high, medium or low integrity. According to the data, only 40.5% of the world’s remaining forests still have high integrity. And even within this category, most forests have experienced at least a small degree of human modification.&nbsp;</p>



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<p>High-integrity forests are concentrated mainly in the boreal forests of northern Russia, Canada and Alaska, as well as across the tropics in parts of the Amazon, the humid forests of Central Africa and the island of New Guinea. </p>



<p>Some smaller but still highly important patches also survive in other regions, including Mesoamerica, Madagascar, West Africa, Sumatra, Borneo and mainland Southeast Asia. Effective protected area management, action by Indigenous Peoples and local communities, difficult terrain and remote locations that deter industrial activity all contribute to forest integrity remaining high in these places.&nbsp;&nbsp;</p>



<h2 class="wp-block-heading">Where is forest integrity at risk?&nbsp;</h2>



<p>Hardly any forest on Earth is wholly free of human influence. The index shows that 31% of all forests worldwide experience easily observed direct pressures from infrastructure, agriculture or recent tree cover loss, while a further 60% experience some degree of human impact through edge effects and fragmentation. Over 25% are classified as low integrity. &nbsp;</p>



<p>As a result of a history of adverse human modification, low-integrity forests are now prevalent in many regions, including west and central Europe, the southeastern United States, mainland Southeast Asia, the Andes, West Africa, much of China and India, and the Atlantic Forests of Brazil. These low-integrity forests may be dominated by planted trees, including monoculture stands and agroforestry.&nbsp;</p>



<p>But it’s not just the vast expanse of low integrity forests that warrant concern. Many large areas with high-integrity forests are also experiencing <a href="https://www.globalforestwatch.org/blog/data-and-research/global-tree-cover-loss-data-2020/" target="_blank" rel="noreferrer noopener">high rates of tree cover loss</a> and degradation, particularly in Brazil and the Democratic Republic of the Congo. </p>



<p>In 2020 alone, these two countries lost 1.7 million hectares and 0.5 million hectares of primary forest, respectively. High-integrity forests are not necessarily legally protected from development; they can be highly threatened by encroaching human activities. Less than half of forests in every biome have high integrity, and of these, only a quarter are located in legally protected areas.&nbsp;</p>



<p>Governments and other actors must protect and monitor the world’s remaining high-integrity and medium-integrity forests, and protect and restore areas of low integrity.&nbsp;</p>



<h2 class="wp-block-heading">Why does forest integrity get less attention than deforestation?&nbsp;</h2>



<p>Deforestation is easier to measure than integrity. While there have been substantial improvements in our ability to monitor forest loss and gain in the past decade, consistent monitoring of forest integrity has proven more elusive until now.&nbsp;&nbsp;</p>



<p>In recent years, pioneering maps of <a href="https://www.globalforestwatch.org/map/?map=eyJkYXRhc2V0cyI6W3siZGF0YXNldCI6ImludGFjdC1mb3Jlc3QtbGFuZHNjYXBlcyIsIm9wYWNpdHkiOjEsInZpc2liaWxpdHkiOnRydWUsImxheWVycyI6WyJpbnRhY3QtZm9yZXN0LWxhbmRzY2FwZXMiXX0seyJkYXRhc2V0IjoicG9saXRpY2FsLWJvdW5kYXJpZXMiLCJsYXllcnMiOlsiZGlzcHV0ZWQtcG9saXRpY2FsLWJvdW5kYXJpZXMiLCJwb2xpdGljYWwtYm91bmRhcmllcyJdLCJvcGFjaXR5IjoxLCJ2aXNpYmlsaXR5Ijp0cnVlfV19" target="_blank" rel="noreferrer noopener">intact forest landscapes</a> and wilderness areas have identified tracts of high integrity, but because they use a binary classification, they cannot tell us about the variation in integrity outside the most intact areas. </p>



<p>Technical challenges and lack of data have historically made it difficult to monitor the nuances of forest integrity, especially since activities like selective logging are difficult to detect in satellite imagery, and the forest canopy obscures many activities that are harmful to forests.&nbsp;&nbsp;</p>



<p>The Forest Landscape Integrity Index accounts for this nuance at a global scale for the first time by estimating integrity along a spectrum. We can expect further advances in mapping and monitoring forest integrity as datasets and processing capabilities continue to improve.&nbsp;</p>



<h2 class="wp-block-heading">What can we do to protect high-integrity forests and restore other forests?&nbsp;</h2>



<p>While policy targets for deforestation are usually precise and ambitious, targets for degradation and forest integrity are often vague or absent entirely. The new data provide a transparent and credible tool that policymakers and other decision-makers can use to set quantified targets, create evidence-based plans, enhance monitoring, and retain and restore the ecological integrity of forests. </p>



<p>For example, governments could create and report on measurable, time-bound goals for maintaining or enhancing forest integrity within treaties such as the post-2020 Global Biodiversity Framework, countries’ Nationally Determined Contributions (NDCs) under the Paris Agreement and several UN Sustainable Development Goals.&nbsp;&nbsp;</p>



<p>Setting such policy goals can encourage governments and other stakeholders to invest in better forest management and restoration. They can formally recognize high-integrity forests, prioritize them in spatial planning, and place them under effective management schemes, such as through designated protected areas or Indigenous control. </p>



<p>Decision-makers can also identify low- and medium-integrity areas and target them for more sustainable management and/or restoration.&nbsp;&nbsp;</p>



<p>In parallel, corporate zero-deforestation commitments must go further to incorporate and monitor forest integrity in businesses’ supply chains. Zero-deforestation commitments do not address the problem of declining forest integrity so long as it falls short of outright deforestation.&nbsp;&nbsp;</p>



<p>Keeping healthy, high-integrity forests functioning at their full potential can be a key part of the solution to global climate, biodiversity, inequality and health crises. We’ll lose many of these important ecosystem services if only degraded, low-integrity forests are left standing. Keeping global commitments such as the recent <a href="https://www.wri.org/insights/what-cop26-means-forests-climate#:~:text=What%20Was%20Promised%20on%20Forests,and%20maintaining%20healthy%20ecosystem%20services." target="_blank" rel="noreferrer noopener">Glasgow Leaders’ Declaration on Forests</a> within reach means we need to incorporate both deforestation <em>and</em> integrity into policy planning. &nbsp;</p>



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Originally appeared on <a href="https://www.wri.org/insights/why-preserving-forest-integrity-preventing-deforestation" target="_blank" rel="noopener noreferrer">WRI Insights</a>. 


 

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Why Preserving Forest Integrity Is As Vital As Preventing Deforestation

<p>Most people point to deforestation — the clearing or burning of forests to make way for a different land-use, such as agriculture — as the greatest threat facing the world’s forests. But there’s another issue that’s just as important: forest integrity.&nbsp;</p>



<p>Forest integrity refers to the health of the forest that remains standing, including its ability to store carbon, protect biodiversity, and provide social and economic benefits. Though equally important, forest integrity is harder to measure than deforestation. </p>



<p>The Forest Landscape Integrity Index on <a href="https://gfw.global/3tKOYUP" target="_blank" rel="noreferrer noopener">Global Forest Watch </a>tracks forest integrity globally for the first time and shows that <strong>less than half of the world’s remaining forests have high integrity.&nbsp;&nbsp;</strong></p>



<p>Here, we explain what forest integrity is and examine the health of the world’s remaining forests.&nbsp;</p>



<h2 class="wp-block-heading">What is forest integrity?&nbsp;</h2>



<p>Forest integrity is defined by scientists as the degree to which a forest’s structure, composition and function are free from modification by humans. It exists as a spectrum, with very high-integrity forests on one end and very low-integrity, severely degraded forests on the other. </p>



<p>Minimal human influence is associated with high forest integrity; as more and more human activities affect a forest — such as logging, human-caused fires or farming — integrity declines. A high-integrity forest usually provides more environmental benefits than a forest of lower integrity. For example, high-integrity forests are generally more effective at: </p>



<ul>
<li>Slowing the pace of climate change by sequestering and storing carbon</li>



<li>Regulating water flows by stabilizing soils</li>



<li>Maintaining rainfall patterns through evapotranspiration</li>



<li>Providing habitat for forest-dependent animals</li>



<li>Supporting Indigenous Peoples’ and local communities’ livelihoods and cultural traditions</li>



<li><a href="https://sdg.iisd.org/commentary/guest-articles/preventing-future-pandemics-starts-with-protecting-our-forests/" target="_blank" rel="noreferrer noopener">Preventing future pandemics</a> by limiting the spread of zoonotic diseases. </li>
</ul>



<p>High-integrity forests are also typically more resilient to the impacts of climate change, such as the warmer, drier conditions that can lead to forest fires.&nbsp;</p>



<div class="imagecenter"><img class=" wp-image-3569 alignright" style="padding-bottom: 10px;" alt="How we measure forest integrity, how it degrades, and what happens when it is lost" src="https://content.globalforestwatch.org/wp-content/uploads/2022/04/22.03.23-Forest-integrity-v3_Formatted-for-Insights-1-2.png" width="100%"></div>



<h2 class="wp-block-heading">What are the biggest threats to forest integrity?&nbsp;&nbsp;</h2>



<p>Forests can be degraded directly by a wide range of human activities, including intensive logging, human-caused fires and over-hunting.&nbsp;&nbsp;</p>



<p>They can also be degraded in less visible ways by fragmentation, and by the “edge effects” that spill over from adjacent human activities such as infrastructure development, farming and urbanization. </p>



<p>A forest edge is more exposed and accessible than its interior, leaving it more susceptible to human activities like wood fuel extraction, hunting, livestock grazing, burning and the spread of invasive species, and more vulnerable to conditions such as direct sunlight, high winds, heatwaves and droughts. &nbsp;</p>



<aside id="textbox"> <div><em><b>How the Forest Landscape Integrity Index works </b><br><br>The Forest Landscape Integrity Index estimates the loss of integrity in a given area of forest by combining observed reductions in forest connectivity with proxy data on the intensity of human activities known to degrade forests. Some of these activities are observed directly as part of the analysis, specifically infrastructure, agriculture and recent deforestation. The associated edge effects cannot readily be observed, so they are estimated using models based on field studies.   
</em></div> </aside>



<h2 class="wp-block-heading">Where are the world’s remaining high-integrity forests?&nbsp;</h2>



<p>The Forest Landscape Integrity Index examines forest integrity along a spectrum and categorizes forests as high, medium or low integrity. According to the data, only 40.5% of the world’s remaining forests still have high integrity. And even within this category, most forests have experienced at least a small degree of human modification.&nbsp;</p>



<div class="flourish-embed flourish-photo-slider" data-src="visualisation/9174019?240776"><script src="https://public.flourish.studio/resources/embed.js"></script></div>



<p>High-integrity forests are concentrated mainly in the boreal forests of northern Russia, Canada and Alaska, as well as across the tropics in parts of the Amazon, the humid forests of Central Africa and the island of New Guinea. </p>



<p>Some smaller but still highly important patches also survive in other regions, including Mesoamerica, Madagascar, West Africa, Sumatra, Borneo and mainland Southeast Asia. Effective protected area management, action by Indigenous Peoples and local communities, difficult terrain and remote locations that deter industrial activity all contribute to forest integrity remaining high in these places.&nbsp;&nbsp;</p>



<h2 class="wp-block-heading">Where is forest integrity at risk?&nbsp;</h2>



<p>Hardly any forest on Earth is wholly free of human influence. The index shows that 31% of all forests worldwide experience easily observed direct pressures from infrastructure, agriculture or recent tree cover loss, while a further 60% experience some degree of human impact through edge effects and fragmentation. Over 25% are classified as low integrity. &nbsp;</p>



<p>As a result of a history of adverse human modification, low-integrity forests are now prevalent in many regions, including west and central Europe, the southeastern United States, mainland Southeast Asia, the Andes, West Africa, much of China and India, and the Atlantic Forests of Brazil. These low-integrity forests may be dominated by planted trees, including monoculture stands and agroforestry.&nbsp;</p>



<p>But it’s not just the vast expanse of low integrity forests that warrant concern. Many large areas with high-integrity forests are also experiencing <a href="https://www.globalforestwatch.org/blog/data-and-research/global-tree-cover-loss-data-2020/" target="_blank" rel="noreferrer noopener">high rates of tree cover loss</a> and degradation, particularly in Brazil and the Democratic Republic of the Congo. </p>



<p>In 2020 alone, these two countries lost 1.7 million hectares and 0.5 million hectares of primary forest, respectively. High-integrity forests are not necessarily legally protected from development; they can be highly threatened by encroaching human activities. Less than half of forests in every biome have high integrity, and of these, only a quarter are located in legally protected areas.&nbsp;</p>



<p>Governments and other actors must protect and monitor the world’s remaining high-integrity and medium-integrity forests, and protect and restore areas of low integrity.&nbsp;</p>



<h2 class="wp-block-heading">Why does forest integrity get less attention than deforestation?&nbsp;</h2>



<p>Deforestation is easier to measure than integrity. While there have been substantial improvements in our ability to monitor forest loss and gain in the past decade, consistent monitoring of forest integrity has proven more elusive until now.&nbsp;&nbsp;</p>



<p>In recent years, pioneering maps of <a href="https://www.globalforestwatch.org/map/?map=eyJkYXRhc2V0cyI6W3siZGF0YXNldCI6ImludGFjdC1mb3Jlc3QtbGFuZHNjYXBlcyIsIm9wYWNpdHkiOjEsInZpc2liaWxpdHkiOnRydWUsImxheWVycyI6WyJpbnRhY3QtZm9yZXN0LWxhbmRzY2FwZXMiXX0seyJkYXRhc2V0IjoicG9saXRpY2FsLWJvdW5kYXJpZXMiLCJsYXllcnMiOlsiZGlzcHV0ZWQtcG9saXRpY2FsLWJvdW5kYXJpZXMiLCJwb2xpdGljYWwtYm91bmRhcmllcyJdLCJvcGFjaXR5IjoxLCJ2aXNpYmlsaXR5Ijp0cnVlfV19" target="_blank" rel="noreferrer noopener">intact forest landscapes</a> and wilderness areas have identified tracts of high integrity, but because they use a binary classification, they cannot tell us about the variation in integrity outside the most intact areas. </p>



<p>Technical challenges and lack of data have historically made it difficult to monitor the nuances of forest integrity, especially since activities like selective logging are difficult to detect in satellite imagery, and the forest canopy obscures many activities that are harmful to forests.&nbsp;&nbsp;</p>



<p>The Forest Landscape Integrity Index accounts for this nuance at a global scale for the first time by estimating integrity along a spectrum. We can expect further advances in mapping and monitoring forest integrity as datasets and processing capabilities continue to improve.&nbsp;</p>



<h2 class="wp-block-heading">What can we do to protect high-integrity forests and restore other forests?&nbsp;</h2>



<p>While policy targets for deforestation are usually precise and ambitious, targets for degradation and forest integrity are often vague or absent entirely. The new data provide a transparent and credible tool that policymakers and other decision-makers can use to set quantified targets, create evidence-based plans, enhance monitoring, and retain and restore the ecological integrity of forests. </p>



<p>For example, governments could create and report on measurable, time-bound goals for maintaining or enhancing forest integrity within treaties such as the post-2020 Global Biodiversity Framework, countries’ Nationally Determined Contributions (NDCs) under the Paris Agreement and several UN Sustainable Development Goals.&nbsp;&nbsp;</p>



<p>Setting such policy goals can encourage governments and other stakeholders to invest in better forest management and restoration. They can formally recognize high-integrity forests, prioritize them in spatial planning, and place them under effective management schemes, such as through designated protected areas or Indigenous control. </p>



<p>Decision-makers can also identify low- and medium-integrity areas and target them for more sustainable management and/or restoration.&nbsp;&nbsp;</p>



<p>In parallel, corporate zero-deforestation commitments must go further to incorporate and monitor forest integrity in businesses’ supply chains. Zero-deforestation commitments do not address the problem of declining forest integrity so long as it falls short of outright deforestation.&nbsp;&nbsp;</p>



<p>Keeping healthy, high-integrity forests functioning at their full potential can be a key part of the solution to global climate, biodiversity, inequality and health crises. We’ll lose many of these important ecosystem services if only degraded, low-integrity forests are left standing. Keeping global commitments such as the recent <a href="https://www.wri.org/insights/what-cop26-means-forests-climate#:~:text=What%20Was%20Promised%20on%20Forests,and%20maintaining%20healthy%20ecosystem%20services." target="_blank" rel="noreferrer noopener">Glasgow Leaders' Declaration on Forests</a> within reach means we need to incorporate both deforestation <em>and</em> integrity into policy planning. &nbsp;</p>



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Originally appeared on <a href="https://www.wri.org/insights/why-preserving-forest-integrity-preventing-deforestation" target="_blank" rel="noopener noreferrer">WRI Insights</a>. 


 

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Preserving forest integrity is as vital as preventing deforestation, but less than half of the world's remaining forests have high integrity.

Importance of Preserving Forest Integrity | Global Forest Watch Blog

Edie Juno

John-Rob Pool


<p>Water is essential to human health and well-being. In cities, leaders strive to provide secure access to clean, safe and affordable water. In rural areas, farmers hope for adequate rain and healthy rivers to produce healthy crops. The COVID-19 pandemic reminds us how <a href="https://www.wri.org/blog/2020/04/coronavirus-water-scarcity-hand-washing" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">critical clean water is to health and hygiene</a>, as public health officials have urged frequent handwashing. And yet, the world is on the precipice of a historic global water crisis. Rising temperatures and extreme weather events associated with climate change continue to pressure water systems and strain urban water infrastructure. Some scenarios suggest that by 2025, as many as <a href="http://www.unesco.org/new/en/natural-sciences/environment/water/wwap/wwdr/wwdr4-2012/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">1.8 billion people will face water scarcity</a>. </p>



<p>The situation is dire, but one asset is already at our fingertips: forests. Within city limits, across local watersheds and even thousands of miles away, forests alter the movement, quality and availability of water. The world’s urban leaders need to account for the role of forests in securing clean water for residents and the agricultural lands that cities rely on.</p>



<p>The connection between cities, water and forests works at three levels: inner forests, nearby forests and faraway forests. Here’s how each one protects water in cities, no matter how far away:</p>



<h3 class="wp-block-heading">Urban Forests Assist Stormwater Management</h3>



<p>Urban water woes are not limited to water scarcity. New research from <a href="https://www.wri.org/applications/aqueduct/floods/?p=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" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Aqueduct Floods</a> suggests that flooding has caused over <a href="https://www.wri.org/news/2020/04/release-new-data-shows-millions-people-trillions-property-risk-flooding-infrastructure" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">$1 trillion</a> in losses globally since 1980, and cities, often situated near coasts and along rivers, are among the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/urban-flooding" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">most vulnerable</a>.</p>



<p>As a <a href="https://www.wri.org/blog/2020/05/3-steps-scaling-nature-based-solutions-climate-adaptation" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">nature-based solution</a>, urban forests — which include all the trees in an urban area, from street trees to patches of natural and planted forest, as well as the vegetation and soil beneath them — can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134866/pdf/nihms-1504240.pdf" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">facilitate improved urban water management</a> and reduce the hazards posed by flooding while simultaneously providing other environmental and <a href="https://www.sciencedirect.com/science/article/abs/pii/S1618866716300097" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">cultural co-benefits</a>.</p>



<p>Trees intercept rainfall as water clings to leaves and branches, slowing its journey across the landscape. This reduces the overall volume of surface runoff, curtails soil erosion and increases groundwater recharge. As a result, urban forests mitigate the effects of storms and flooding events on traditional infrastructure like drains and dikes. This also reduces risks from <a href="https://www3.epa.gov/region1/eco/uep/cso.html" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">combined sewage overflows</a>, which threaten the health of communities and aquatic ecosystems. Given the benefits, U.S. cities like <a href="https://e360.yale.edu/features/with-a-green-makeover-philadelphia-tackles-its-stormwater-problem" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Philadelphia</a> and <a href="http://fsprbuhwmilliontrees.nyc.gov/sp/downloads/pdf/nyc_mfra.pdf" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">New York City</a>, as well as <a href="https://www.theguardian.com/world/2017/dec/28/chinas-sponge-cities-are-turning-streets-green-to-combat-flooding" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">China’s many “sponge cities,”</a> are actively incorporating trees and other green infrastructure to manage stormwater and flooding risks and improve infiltration rates across their cities.</p>



<h3 class="wp-block-heading"><strong>Nearby Forests Protect Water Supplies and Enhance Resilience</strong></h3>



<p>Of the world’s 105 largest cities, <a href="https://openknowledge.worldbank.org/handle/10986/15006" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">33 rely heavily on nearby protected forest lands</a> as a primary factor in drinking water availability and quality. Five major cities in the U.S. — New York; Boston; San Francisco; Seattle and Portland, Oregon — <a href="https://www.nytimes.com/2018/01/18/nyregion/new-york-city-water-filtration.html" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">rely on nearby protected forests</a> instead of mechanical infrastructure to filter their water.</p>



<p>Forested watersheds adjacent to cities affect water quality and availability by <a href="https://www.wri.org/blog/2017/03/3-surprising-ways-water-depends-healthy-forests" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">regulating</a> precipitation, evaporation and flows. Trees and other vegetation can improve water quality by preventing erosion, breaking down pollutants and providing shade. Forests and their soils also act like sponges that absorb water when it is plentiful and release it when it is scarce. They do this partly by increasing water infiltration into the soil, helping to recharge vital groundwater supplies.</p>



<p>Studies from WRI suggest that protecting these watershed ecosystems can pay off in countries like Brazil. By protecting water quality and preventing sediment from entering waterways, restoring forests around Rio de Janeiro could help the city avoid <a href="https://www.wri.org/blog/2018/12/restoring-rio-de-janeiro-s-forests-could-save-79-million-water-treatment-costs" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">$79 million in costs for water treatment</a> and reduce use of chemical products by as much as 4 million tons.</p>



<p>However, not all forests are provide the same benefits. Converting natural grasslands to forests and the use of non-native trees in plantations may reduce surface water yields for decades. In South Africa, for example, <a href="https://theconversation.com/south-africa-needs-a-fresh-approach-to-managing-invasive-trees-like-eucalyptus-126777" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">water-intensive Eucalyptus trees</a> have stressed limited water resources. Conserving existing forests and considering local climate constraints may help to avoid negative unintended consequences.</p>



<h3 class="wp-block-heading"><strong>Faraway Forests Drive Regional and Global Rainfall</strong></h3>



<p>From hundreds of miles away, forests influence precipitation patterns for cities and key agricultural regions. A growing body of research acknowledges the role of tropical forests in creating “<a href="http://www.fao.org/in-action/forest-and-water-programme/news/news-detail/en/c/1190278/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">flying rivers</a>”: Trees act as giant straws, pulling water from the soil and transpiring it into the air to produce the <a href="https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">water vapor needed for rainfall</a>, often in <a href="https://www.sciencedirect.com/science/article/pii/S0959378017300134" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">regions far downwind</a>.</p>



<p>The world’s great tropical forests in the Amazon Basin, the Congo Basin and Southeast Asia play an especially important role in regulating rain. However, the ability of these forests to contribute rainfall is in jeopardy. The world <a href="https://gfw.global/32l4OWP" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">lost 11.9 million hectares (29.4 million acres) of forest in 2019</a> —including 3.8 million hectares (9.4 million acres) of mature tropical rainforest. Cascading, deforestation-driven changes in rainfall could increase drought in urban regions and key farmlands, <a href="https://www.nature.com/articles/nclimate2430" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">in the tropics and far beyond</a>.</p>



<p><a href="https://wriorg.s3.amazonaws.com/s3fs-public/ending-tropical-deforestation-tropical-forests-climate-change.pdf" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Research</a> suggests that large-scale deforestation of the Congo Basin would leave parts of Africa, like the populous Nile Basin and the <a href="https://www.wri.org/blog/2019/07/congo-basin-deforestation-threatens-food-and-water-supplies-throughout-africa" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Sahel</a>, hotter and drier. In Latin America, degradation in the Amazon could lead cities in Brazil, Paraguay, Uruguay and Argentina to experience <a href="https://advances.sciencemag.org/content/4/2/eaat2340.full" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">longer dry seasons and reduced agricultural productivity</a>. &nbsp;</p>



<h3 class="wp-block-heading"><strong>Improving Water and Cities By Protecting Forests</strong></h3>



<p>With the <a href="https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">majority of the planet’s population inhabiting cities</a>, decisions made within urban boundaries affect these tropical forests. The production of commodities like beef, soy and palm oil drove <a href="https://science.sciencemag.org/content/361/6407/1108" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">nearly 30% of global tree cover loss</a> in recent decades. Urban areas consume <a href="https://www.resourcepanel.org/reports/weight-cities" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">roughly 40 billion tons</a> of materials annually — a number expected to more than double by 2050.</p>



<p>As centers of commerce and culture, cities can stem these losses when municipal governments adopt deforestation-free procurement policies — as governments in <a href="https://www.regnskog.no/en/news/norwegian-state-commits-to-zero-deforestation-1" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Norway</a> and <a href="https://foe.org/news/new-california-bill-address-products-linked-deforestation-climate-change/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">California</a> are exploring — and champion the value of forest conservation. At the same time, corporations can embrace forest-friendly supply chains, using open-source tools like <a href="https://pro.globalforestwatch.org/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Global Forest Watch Pro</a>. Many cities, recognizing the connection between forests and water, are acting to support and conserve forests. Members of the <a href="https://cities4forests.com/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Cities4Forests</a> network are working to plan and develop urban green infrastructure, invest in protecting watershed forests and source more forest-friendly commodities. As voters, consumers and ratepayers, city residents have a crucial role to play. Forests protect water for cities, and it is essential that cities step up to protect forests in return.</p>



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Visit <a href="https://cities4forests.com/" target="_blank" rel="noopener noreferrer">Cities4Forests</a> to learn more about what cities are doing and how you can get involved. 

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Originally appeared on <a href="[INSIGHTS URL]" target="_blank" rel="noopener noreferrer">WRI Insights</a>. 
 

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Forests Near or Far Can Protect Water for Cities

<p>Water is essential to human health and well-being. In cities, leaders strive to provide secure access to clean, safe and affordable water. In rural areas, farmers hope for adequate rain and healthy rivers to produce healthy crops. The COVID-19 pandemic reminds us how <a href="https://www.wri.org/blog/2020/04/coronavirus-water-scarcity-hand-washing" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">critical clean water is to health and hygiene</a>, as public health officials have urged frequent handwashing. And yet, the world is on the precipice of a historic global water crisis. Rising temperatures and extreme weather events associated with climate change continue to pressure water systems and strain urban water infrastructure. Some scenarios suggest that by 2025, as many as <a href="http://www.unesco.org/new/en/natural-sciences/environment/water/wwap/wwdr/wwdr4-2012/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">1.8 billion people will face water scarcity</a>. </p>



<p>The situation is dire, but one asset is already at our fingertips: forests. Within city limits, across local watersheds and even thousands of miles away, forests alter the movement, quality and availability of water. The world’s urban leaders need to account for the role of forests in securing clean water for residents and the agricultural lands that cities rely on.</p>



<p>The connection between cities, water and forests works at three levels: inner forests, nearby forests and faraway forests. Here’s how each one protects water in cities, no matter how far away:</p>



<h3 class="wp-block-heading">Urban Forests Assist Stormwater Management</h3>



<p>Urban water woes are not limited to water scarcity. New research from <a href="https://www.wri.org/applications/aqueduct/floods/?p=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" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Aqueduct Floods</a> suggests that flooding has caused over <a href="https://www.wri.org/news/2020/04/release-new-data-shows-millions-people-trillions-property-risk-flooding-infrastructure" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">$1 trillion</a> in losses globally since 1980, and cities, often situated near coasts and along rivers, are among the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/urban-flooding" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">most vulnerable</a>.</p>



<p>As a <a href="https://www.wri.org/blog/2020/05/3-steps-scaling-nature-based-solutions-climate-adaptation" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">nature-based solution</a>, urban forests — which include all the trees in an urban area, from street trees to patches of natural and planted forest, as well as the vegetation and soil beneath them — can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134866/pdf/nihms-1504240.pdf" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">facilitate improved urban water management</a> and reduce the hazards posed by flooding while simultaneously providing other environmental and <a href="https://www.sciencedirect.com/science/article/abs/pii/S1618866716300097" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">cultural co-benefits</a>.</p>



<p>Trees intercept rainfall as water clings to leaves and branches, slowing its journey across the landscape. This reduces the overall volume of surface runoff, curtails soil erosion and increases groundwater recharge. As a result, urban forests mitigate the effects of storms and flooding events on traditional infrastructure like drains and dikes. This also reduces risks from <a href="https://www3.epa.gov/region1/eco/uep/cso.html" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">combined sewage overflows</a>, which threaten the health of communities and aquatic ecosystems. Given the benefits, U.S. cities like <a href="https://e360.yale.edu/features/with-a-green-makeover-philadelphia-tackles-its-stormwater-problem" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Philadelphia</a> and <a href="http://fsprbuhwmilliontrees.nyc.gov/sp/downloads/pdf/nyc_mfra.pdf" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">New York City</a>, as well as <a href="https://www.theguardian.com/world/2017/dec/28/chinas-sponge-cities-are-turning-streets-green-to-combat-flooding" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">China’s many “sponge cities,”</a> are actively incorporating trees and other green infrastructure to manage stormwater and flooding risks and improve infiltration rates across their cities.</p>



<h3 class="wp-block-heading"><strong>Nearby Forests Protect Water Supplies and Enhance Resilience</strong></h3>



<p>Of the world’s 105 largest cities, <a href="https://openknowledge.worldbank.org/handle/10986/15006" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">33 rely heavily on nearby protected forest lands</a> as a primary factor in drinking water availability and quality. Five major cities in the U.S. — New York; Boston; San Francisco; Seattle and Portland, Oregon — <a href="https://www.nytimes.com/2018/01/18/nyregion/new-york-city-water-filtration.html" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">rely on nearby protected forests</a> instead of mechanical infrastructure to filter their water.</p>



<p>Forested watersheds adjacent to cities affect water quality and availability by <a href="https://www.wri.org/blog/2017/03/3-surprising-ways-water-depends-healthy-forests" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">regulating</a> precipitation, evaporation and flows. Trees and other vegetation can improve water quality by preventing erosion, breaking down pollutants and providing shade. Forests and their soils also act like sponges that absorb water when it is plentiful and release it when it is scarce. They do this partly by increasing water infiltration into the soil, helping to recharge vital groundwater supplies.</p>



<p>Studies from WRI suggest that protecting these watershed ecosystems can pay off in countries like Brazil. By protecting water quality and preventing sediment from entering waterways, restoring forests around Rio de Janeiro could help the city avoid <a href="https://www.wri.org/blog/2018/12/restoring-rio-de-janeiro-s-forests-could-save-79-million-water-treatment-costs" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">$79 million in costs for water treatment</a> and reduce use of chemical products by as much as 4 million tons.</p>



<p>However, not all forests are provide the same benefits. Converting natural grasslands to forests and the use of non-native trees in plantations may reduce surface water yields for decades. In South Africa, for example, <a href="https://theconversation.com/south-africa-needs-a-fresh-approach-to-managing-invasive-trees-like-eucalyptus-126777" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">water-intensive Eucalyptus trees</a> have stressed limited water resources. Conserving existing forests and considering local climate constraints may help to avoid negative unintended consequences.</p>



<h3 class="wp-block-heading"><strong>Faraway Forests Drive Regional and Global Rainfall</strong></h3>



<p>From hundreds of miles away, forests influence precipitation patterns for cities and key agricultural regions. A growing body of research acknowledges the role of tropical forests in creating “<a href="http://www.fao.org/in-action/forest-and-water-programme/news/news-detail/en/c/1190278/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">flying rivers</a>”: Trees act as giant straws, pulling water from the soil and transpiring it into the air to produce the <a href="https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">water vapor needed for rainfall</a>, often in <a href="https://www.sciencedirect.com/science/article/pii/S0959378017300134" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">regions far downwind</a>.</p>



<p>The world’s great tropical forests in the Amazon Basin, the Congo Basin and Southeast Asia play an especially important role in regulating rain. However, the ability of these forests to contribute rainfall is in jeopardy. The world <a href="https://gfw.global/32l4OWP" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">lost 11.9 million hectares (29.4 million acres) of forest in 2019</a> —including 3.8 million hectares (9.4 million acres) of mature tropical rainforest. Cascading, deforestation-driven changes in rainfall could increase drought in urban regions and key farmlands, <a href="https://www.nature.com/articles/nclimate2430" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">in the tropics and far beyond</a>.</p>



<p><a href="https://wriorg.s3.amazonaws.com/s3fs-public/ending-tropical-deforestation-tropical-forests-climate-change.pdf" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Research</a> suggests that large-scale deforestation of the Congo Basin would leave parts of Africa, like the populous Nile Basin and the <a href="https://www.wri.org/blog/2019/07/congo-basin-deforestation-threatens-food-and-water-supplies-throughout-africa" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Sahel</a>, hotter and drier. In Latin America, degradation in the Amazon could lead cities in Brazil, Paraguay, Uruguay and Argentina to experience <a href="https://advances.sciencemag.org/content/4/2/eaat2340.full" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">longer dry seasons and reduced agricultural productivity</a>. &nbsp;</p>



<h3 class="wp-block-heading"><strong>Improving Water and Cities By Protecting Forests</strong></h3>



<p>With the <a href="https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">majority of the planet’s population inhabiting cities</a>, decisions made within urban boundaries affect these tropical forests. The production of commodities like beef, soy and palm oil drove <a href="https://science.sciencemag.org/content/361/6407/1108" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">nearly 30% of global tree cover loss</a> in recent decades. Urban areas consume <a href="https://www.resourcepanel.org/reports/weight-cities" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">roughly 40 billion tons</a> of materials annually — a number expected to more than double by 2050.</p>



<p>As centers of commerce and culture, cities can stem these losses when municipal governments adopt deforestation-free procurement policies — as governments in <a href="https://www.regnskog.no/en/news/norwegian-state-commits-to-zero-deforestation-1" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Norway</a> and <a href="https://foe.org/news/new-california-bill-address-products-linked-deforestation-climate-change/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">California</a> are exploring — and champion the value of forest conservation. At the same time, corporations can embrace forest-friendly supply chains, using open-source tools like <a href="https://pro.globalforestwatch.org/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Global Forest Watch Pro</a>. Many cities, recognizing the connection between forests and water, are acting to support and conserve forests. Members of the <a href="https://cities4forests.com/" target="_blank" aria-label="undefined (opens in a new tab)" rel="noreferrer noopener">Cities4Forests</a> network are working to plan and develop urban green infrastructure, invest in protecting watershed forests and source more forest-friendly commodities. As voters, consumers and ratepayers, city residents have a crucial role to play. Forests protect water for cities, and it is essential that cities step up to protect forests in return.</p>



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<div class="attribute" style="”padding-bottom:" 10px;”=""> 
Visit <a href="https://cities4forests.com/" target="_blank" rel="noopener noreferrer">Cities4Forests</a> to learn more about what cities are doing and how you can get involved. 

<p></p>
Originally appeared on <a href="[INSIGHTS URL]" target="_blank" rel="noopener noreferrer">WRI Insights</a>. 
 

</div> 

 

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Water is essential to human health and well-being. Forests can help provide cities with secure access to clean, safe and affordable water.

Forests Near or Far Can Protect Water for Cities | GFW Blog

https://secure.gravatar.com/avatar/3dc298e411f65b199fc3734919d6934e?s=96&d=mm&r=g

Sarah Ruiz

<div class="imageright"><img decoding="async" class="aligncenter wp-image-4155" style="padding-bottom: 10px;" src="https://content.globalforestwatch.org/wp-content/uploads/2017/03/5252477899_a53c92eb16_z.jpg" alt="alt text" width="100%" />Deforestation in the Amazon can affect rainfall in places as far away as Texas. Photo by Katja Schulz/Flickr</div>
<p>By <a href="http://www.wri.org/profile/katie-fletcher" target="_blank" rel="noopener noreferrer">Katie Fletcher</a> and <a href="http://www.wri.org/profile/todd-gartner" target="_blank" rel="noopener noreferrer">Todd Gartner</a></p>
<p>Healthy forests are critical to providing clean water. Forests can positively impact the quantity, quality and filtration costs associated with a city’s water, sometimes even reducing the need for costly concrete and steel infrastructure. The world’s major <a href="http://www.wri.org/sites/default/files/wri16_TECH_GFW-Water_draft7.pdf" target="_blank" rel="noopener noreferrer">watersheds lost 6 percent of their tree cover</a> on average from 2000-2014. Today, about <a href="http://www.wri.org/sites/default/files/wri16_TECH_GFW-Water_draft7.pdf" target="_blank" rel="noopener noreferrer">31 percent of the world’s watershed</a> area is covered by forests. Deforestation in these watersheds, often caused by commodity and agricultural production, can contaminate water, fuel floods and drought, and lead to higher water treatment costs. It’s fitting that the <a href="http://www.un.org/en/events/forestsday/" target="_blank" rel="noopener noreferrer">International Day of Forests</a> (on March 21) and <a href="http://www.worldwaterday.org/" target="_blank" rel="noopener noreferrer">World Water Day</a> (on March 22) fall next to each other, as the health of these important resources often go hand-in-hand. To celebrate this year, let’s look at just how big of a role forests play in providing clean water:</p>
<div class="imagecenter"><img decoding="async" class="aligncenter wp-image-4155" style="padding-bottom: 10px;" src="https://content.globalforestwatch.org/wp-content/uploads/2017/03/17_INFO_GFW_WATER-01.png" alt="alt text" width="100%" /></div>
<h3>1. The Quality of Water</h3>
<p>Erosion—when rainfall, runoff or wind detach soil particles—is a significant problem that affects both water quality and quantity. Healthy forests act as a filter to keep pollution out of water. Strong roots anchor soil against erosion and material on the forest floor helps absorb nutrients and sediment. But when forests are disturbed and degraded, sediment flows into streams and pollutes water. In the early 2000s, Colorado experienced wildfires that degraded forests along the Front Range. Extreme ash and debris from the fires made its way into key waterways, forcing Denver’s water utility, <a href="http://www.denverwater.org/AboutUs/ServiceArea/" target="_blank" rel="noopener noreferrer">which serves 1.4 million people</a>, to temporarily rely upon back-up reservoirs. Cleaning up this erosion alone <a href="http://www.wri.org/sites/default/files/wri13_report_4c_naturalinfrastructure_v2.pdf" target="_blank" rel="noopener noreferrer">cost Denver’s water utility $26 million</a>.</p>
<h3>2. The Availability of Water</h3>
<p>Forests help control the water cycle by regulating precipitation, evaporation and flows. Layers of forest canopy, branches and roots can store and release water vapor, which controls rainfall. Forests can also help reduce the impacts of flood from storms by blocking and slowing down the flow of runoff. Deforestation weakens this process, leading to irregular rainfall patterns including drought and flooding. While deforestation may occur locally, its effect is global. <a href="http://www.greenpeace.org/international/Global/international/publications/forests/2013/JN455-An-Impending-Storm.pdf" target="_blank" rel="noopener noreferrer">According to Greenpeace</a>, deforestation in Central Africa could decrease rainfall in the U.S. Midwest by 5-35 percent. Texas alone could see a 25 percent decrease in rainfall after Amazon deforestation, affecting agricultural productivity and other sectors.</p>
<h3>3. The Cost of Water Treatment</h3>
<p>Communities often rely on expensive water filtration infrastructure to ensure clean water. This cost often increases when erosion deteriorates water quality. Relying on natural infrastructure like forests, as a complement to traditional built infrastructure, is <a href="http://www.wri.org/sites/default/files/Protecting_Drinking_Water_at_the_Source.pdf" target="_blank" rel="noopener noreferrer">proven to reduce water management costs</a> and provides both economic and cultural benefits like recreational green spaces and fish and wildlife habitats. New York City, for example, conserved forest and natural landscapes in the Catskills to save on water filtration costs. The <a href="http://www.wri.org/sites/default/files/wri13_report_4c_naturalinfrastructure_v2.pdf" target="_blank" rel="noopener noreferrer">city invested $1.5 billion to protect more than 1 million acres of mostly forested watershed area</a>, ultimately avoiding $6-8 billion on the cost of building a water filtration plant.</p>
<h3>Learn More About Protecting Natural Infrastructure to Improve Water Sourcing</h3>
<p><a href="http://water.globalforestwatch.org/" target="_blank" rel="noopener noreferrer">Global Forest Watch Water</a> (GFW Water) is a free global database and interactive mapping tool designed to help identify deforestation risks to watersheds and opportunities for natural infrastructure solutions. The tool can help downstream beneficiaries, financing and development institutions, civil society and research groups apply natural infrastructure as one of their <a href="http://www.wri.org/publication/protecting-drinking-water-source" target="_blank" rel="noopener noreferrer">strategies to enhance water security and improve watershed management</a>.</p>
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<div class="attribute">BANNER PHOTO: Deforestation in the Amazon can affect rainfall in places as far away as Texas. Photo by Katja Schulz/Flickr.</div>
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3 Surprising Ways Water Depends on Healthy Forests

<div class="imageright"><img class="aligncenter wp-image-4155" style="padding-bottom: 10px;" src="https://content.globalforestwatch.org/wp-content/uploads/2017/03/5252477899_a53c92eb16_z.jpg" alt="alt text" width="100%" />Deforestation in the Amazon can affect rainfall in places as far away as Texas. Photo by Katja Schulz/Flickr</div>
By <a href="http://www.wri.org/profile/katie-fletcher" target="_blank" rel="noopener noreferrer">Katie Fletcher</a> and <a href="http://www.wri.org/profile/todd-gartner" target="_blank" rel="noopener noreferrer">Todd Gartner</a>

Healthy forests are critical to providing clean water. Forests can positively impact the quantity, quality and filtration costs associated with a city's water, sometimes even reducing the need for costly concrete and steel infrastructure. The world’s major <a href="http://www.wri.org/sites/default/files/wri16_TECH_GFW-Water_draft7.pdf" target="_blank" rel="noopener noreferrer">watersheds lost 6 percent of their tree cover</a> on average from 2000-2014. Today, about <a href="http://www.wri.org/sites/default/files/wri16_TECH_GFW-Water_draft7.pdf" target="_blank" rel="noopener noreferrer">31 percent of the world’s watershed</a> area is covered by forests. Deforestation in these watersheds, often caused by commodity and agricultural production, can contaminate water, fuel floods and drought, and lead to higher water treatment costs. It’s fitting that the <a href="http://www.un.org/en/events/forestsday/" target="_blank" rel="noopener noreferrer">International Day of Forests</a> (on March 21) and <a href="http://www.worldwaterday.org/" target="_blank" rel="noopener noreferrer">World Water Day</a> (on March 22) fall next to each other, as the health of these important resources often go hand-in-hand. To celebrate this year, let’s look at just how big of a role forests play in providing clean water:
<div class="imagecenter"><img class="aligncenter wp-image-4155" style="padding-bottom: 10px;" src="https://content.globalforestwatch.org/wp-content/uploads/2017/03/17_INFO_GFW_WATER-01.png" alt="alt text" width="100%" /></div>
<h3>1. The Quality of Water</h3>
Erosion—when rainfall, runoff or wind detach soil particles—is a significant problem that affects both water quality and quantity. Healthy forests act as a filter to keep pollution out of water. Strong roots anchor soil against erosion and material on the forest floor helps absorb nutrients and sediment. But when forests are disturbed and degraded, sediment flows into streams and pollutes water. In the early 2000s, Colorado experienced wildfires that degraded forests along the Front Range. Extreme ash and debris from the fires made its way into key waterways, forcing Denver's water utility, <a href="http://www.denverwater.org/AboutUs/ServiceArea/" target="_blank" rel="noopener noreferrer">which serves 1.4 million people</a>, to temporarily rely upon back-up reservoirs. Cleaning up this erosion alone <a href="http://www.wri.org/sites/default/files/wri13_report_4c_naturalinfrastructure_v2.pdf" target="_blank" rel="noopener noreferrer">cost Denver’s water utility $26 million</a>.
<h3>2. The Availability of Water</h3>
Forests help control the water cycle by regulating precipitation, evaporation and flows. Layers of forest canopy, branches and roots can store and release water vapor, which controls rainfall. Forests can also help reduce the impacts of flood from storms by blocking and slowing down the flow of runoff. Deforestation weakens this process, leading to irregular rainfall patterns including drought and flooding. While deforestation may occur locally, its effect is global. <a href="http://www.greenpeace.org/international/Global/international/publications/forests/2013/JN455-An-Impending-Storm.pdf" target="_blank" rel="noopener noreferrer">According to Greenpeace</a>, deforestation in Central Africa could decrease rainfall in the U.S. Midwest by 5-35 percent. Texas alone could see a 25 percent decrease in rainfall after Amazon deforestation, affecting agricultural productivity and other sectors.
<h3>3. The Cost of Water Treatment</h3>
Communities often rely on expensive water filtration infrastructure to ensure clean water. This cost often increases when erosion deteriorates water quality. Relying on natural infrastructure like forests, as a complement to traditional built infrastructure, is <a href="http://www.wri.org/sites/default/files/Protecting_Drinking_Water_at_the_Source.pdf" target="_blank" rel="noopener noreferrer">proven to reduce water management costs</a> and provides both economic and cultural benefits like recreational green spaces and fish and wildlife habitats. New York City, for example, conserved forest and natural landscapes in the Catskills to save on water filtration costs. The <a href="http://www.wri.org/sites/default/files/wri13_report_4c_naturalinfrastructure_v2.pdf" target="_blank" rel="noopener noreferrer">city invested $1.5 billion to protect more than 1 million acres of mostly forested watershed area</a>, ultimately avoiding $6-8 billion on the cost of building a water filtration plant.
<h3>Learn More About Protecting Natural Infrastructure to Improve Water Sourcing</h3>
<a href="http://water.globalforestwatch.org/" target="_blank" rel="noopener noreferrer">Global Forest Watch Water</a> (GFW Water) is a free global database and interactive mapping tool designed to help identify deforestation risks to watersheds and opportunities for natural infrastructure solutions. The tool can help downstream beneficiaries, financing and development institutions, civil society and research groups apply natural infrastructure as one of their <a href="http://www.wri.org/publication/protecting-drinking-water-source" target="_blank" rel="noopener noreferrer">strategies to enhance water security and improve watershed management</a>.

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<div class="attribute">BANNER PHOTO: Deforestation in the Amazon can affect rainfall in places as far away as Texas. Photo by Katja Schulz/Flickr.</div>

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