When Tree Cover Loss is Really Forest Loss: New Plantation Maps Improve Forest Monitoring
By Mikaela Weisse The difference between forest and “tree cover” may be subtle, but it is important. Tree cover describes all trees and vegetation taller than 5m (the height at which they can be reliably detected by satellites) regardless of whether they’re part of a natural forest or have been planted by humans for agricultural production. Accordingly, data like the GLAD tree cover loss and gain on Global Forest Watch has been criticized for being unable to distinguish between types of loss like the permanent conversion of natural forests—what most of our users care about—and the harvesting of managed plantations. In response, Global Forest Watch teamed up with Transparent World to map the extent and location of plantations in seven key tropical countries: Brazil, Cambodia, Colombia, Indonesia, Liberia, Malaysia and Peru. The new maps, combined with forest change data on Global Forest Watch, now lets users see not just tree cover loss, but forest loss. Read our launch blog.
Recalibrating Global Trends
Separating forest loss from loss inside plantations can have a major impact on our understanding of global forest change trends. For example, in 2014 Malaysia had the fourth highest tree cover loss in the tropics as a percentage of its total forested area. However, if you only look at loss outside of plantation areas in Malaysia (i.e. loss in natural forest) it would move down to #21. Comparisons were made using loss as a proportion of total forested area to correct for the fact that bigger countries and countries with more forests tend to have greater loss. This is in part because plantations cover almost a third (30.2 percent) of Malaysia’s land area—the country converted much of their remaining natural forests for oil palm and other crops decades ago. Making the distinction helps us understand these complex landscape dynamics and can have a big impact on which areas we prioritize for conservation around the world.
Plantation maps can also be a game changer for those who closely monitor new forest changes using the Global Forest Watch near real-time alerts. Tree cover loss alerts within existing plantations are more likely to reflect routine harvesting. Even when the loss is unplanned, it will likely have lesser impact on ecosystem services than loss in natural forests as plantations often store less carbon and harbor less biodiversity. Therefore, forest managers can use GFW alerts and plantations maps together to better focus limited resources toward higher-conservation value forest areas.
Snapshots Are Just the First Step
Though a powerful addition to the suite of forest change data available on Global Forest Watch, the plantation maps only provide a snapshot of 2013 and 2014 and don’t tell us anything about the land use prior to 2013. For example, tree cover loss in 2012 and earlier seen within mapped plantations could be previous harvest cycles, or it could be clearing of natural forests to establish the plantation (i.e. deforestation). Mapping plantations from 2000 (the farthest back our tree cover change data go) to 2012 would give us a better sense of when plantations were established and therefore where deforestation occurred during that time period. Similarly, we would need regularly updated plantation maps to detect forest loss in the future. But that’s easier said than done. The 2013 and 2014 maps were created through a labor-intensive process (i.e. by hand!) because remote-sensing technologies cannot yet accurately distinguish plantations from natural forests. Still, while we wait for technology to fill the gap, these maps highlight the importance of securing efforts to build upon this work to continue improving forest monitoring systems.
See For Yourself! 5 Ways to Use the New Plantations Data
You can find the plantations data under the “Land Cover” tab on the interactive GFW map, or under the country data for each of the seven countries. Clicking on each individual plantation boundary gives more information on the plantation type (i.e. industrial, small-scale, etc.), area, and the probable species (i.e. oil palm, rubber, fruit, etc.). Here are five ways users can interact with the new plantations data to find the information they care about most:
- Analyze Loss Inside Plantations: Calculate how many hectares of tree cover loss occurred in any plantation by selecting a plantation shape and then clicking the “Analyze” button
- Find Areas of Interest: See where plantations overlap with protected areas, biodiversity hotspots, Intact Forest Landscapes, and other important areas for conservation
- Calculate Carbon Emissions: Find out how much tree cover loss and emissions come from plantations in each of the seven countries on their GFW Climate country profile page
- Download the Data: Get the data from the Open Data Portal and to use in your own analysis
- See Loss Outside Plantations: Learn the area and percent of tree cover loss outside of plantations for the seven countries on their country profiles pages
We hope the new plantation maps are a major step forward in forest monitoring. The data allows us to look past the trees to truly see the forest.