Southeast Asia contains about half of all tropical mountain forests, which are rich in biodiversity and carbon stocks, yet there is debate as to whether regional mountain forest cover has increased or decreased in recent decades. Here, our analysis of high-resolution satellite datasets reveals increasing mountain forest loss across Southeast Asia. Total mean annual forest loss was 3.22 Mha yr−1 during 2001–2019, with 31% occurring on the mountains. In the 2010s, the frontier of forest loss moved to higher elevations (15.1 ± 3.8 m yr−1 during 2011–2019, P < 0.01) and steeper slopes (0.22 ± 0.05° yr−1 during 2009–2019, P < 0.01) that have high forest carbon density relative to the lowlands. These shifts led to unprecedented annual forest carbon loss of 424 Tg C yr−1, accelerating at a rate of 18 ± 4 Tg C yr−2 (P < 0.01) from 2001 to 2019. Our results underscore the immediate threat of carbon stock losses associated with accelerating forest clearance in Southeast Asian mountains, which jeopardizes international climate agreements and biodiversity conservation.
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The global maps of forest-cover loss and gain are available at https://earthenginepartners.appspot.com/science-2013-global-forest/download_v1.7.html. The ASTER elevation data are available at https://earthdata.nasa.gov/. The GMBA inventory is available at https://ilias.unibe.ch/goto_ilias3_unibe_cat_1000515.html. The aboveground biomass maps are available at https://www.globalforestwatch.org/map/global/. The primary extent data are available at https://glad.umd.edu/dataset/primary-forest-humid-tropics. All datasets are also available upon request from the corresponding author.
The scripts used to generate all the results are MATLAB (R2020a). Analysis scripts are available at https://doi.org/10.6084/m9.figshare.14586528.
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Z.Z. and C.Z. were supported by the National Natural Science Foundation of China (grant nos. 42071022, 41861124003 and 41890852). Z.Z. was also supported by the start-up fund provided by Southern University of Science and Technology (no. 29/Y01296122). We thank Hansen/UMD/Google/USGS/NASA for providing the high-resolution forest change and primary forest extent data; NASA and Japan’s Ministry of Economy, Trade and Industry for providing the elevation data; Körner for providing the GMBA inventory; and Zarin/WHRC for providing the aboveground biomass density maps.
The authors declare no competing interests.
Peer review information Nature Sustainability thanks Stephen Leisz, Ensheng Weng, and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
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Feng, Y., Ziegler, A.D., Elsen, P.R. et al. Upward expansion and acceleration of forest clearance in the mountains of Southeast Asia. Nat Sustain 4, 892–899 (2021). https://doi.org/10.1038/s41893-021-00738-y
Nature Sustainability (2022)