Humid tropical forest clearing from 2000 to 2005 quantified by using multitemporal and multiresolution remotely sensed data

doi:10.1073/pnas.0804042105

Humid tropical forest clearing from 2000 to 2005 quantified by using multitemporal and multiresolution remotely sensed data

*South Dakota State University, Brookings, SD 57007;
^†State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210;
^‡United States Geological Survey, Sioux Falls, SD 57103;
^§University of Maryland, College Park, MD 20742;
^‖Indonesian Ministry of Forestry, Jalan Gatot Subroto, Senayan, Jakarta, 10270 Indonesia;
**World Resources Institute, Washington, DC 20002; and
^††Conservation International, Washington, DC 20002

Contributed by Ruth S. DeFries, May 2, 2008 (received for review February 21, 2008)

Abstract

Forest cover is an important input variable for assessing changes to carbon stocks, climate and hydrological systems, biodiversity richness, and other sustainability science disciplines. Despite incremental improvements in our ability to quantify rates of forest clearing, there is still no definitive understanding on global trends. Without timely and accurate forest monitoring methods, policy responses will be uninformed concerning the most basic facts of forest cover change. Results of a feasible and cost-effective monitoring strategy are presented that enable timely, precise, and internally consistent estimates of forest clearing within the humid tropics. A probability-based sampling approach that synergistically employs low and high spatial resolution satellite datasets was used to quantify humid tropical forest clearing from 2000 to 2005. Forest clearing is estimated to be 1.39% (SE 0.084%) of the total biome area. This translates to an estimated forest area cleared of 27.2 million hectares (SE 2.28 million hectares), and represents a 2.36% reduction in area of humid tropical forest. Fifty-five percent of total biome clearing occurs within only 6% of the biome area, emphasizing the presence of forest clearing “hotspots.” Forest loss in Brazil accounts for 47.8% of total biome clearing, nearly four times that of the next highest country, Indonesia, which accounts for 12.8%. Over three-fifths of clearing occurs in Latin America and over one-third in Asia. Africa contributes 5.4% to the estimated loss of humid tropical forest cover, reflecting the absence of current agro-industrial scale clearing in humid tropical Africa.

Footnotes

^¶To whom correspondence should be addressed at:
2181 Lefrak Hall, University of Maryland, College Park, MD 20742.
E-mail: rdefries{at}mail.umd.edu
Author contributions: M.C.H., S.V.S., T.R.L., J.R.G.T., and R.S.D. designed research; M.C.H., S.V.S., P.V.P., T.R.L., K.W.P., and M.K.S. performed research; M.C.H., S.V.S., P.V.P., K.W.P., B.A., F.S., M.K.S., M.C., and C.D. analyzed data; and M.C.H., S.V.S., P.V.P., and R.S.D. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0804042105/DCSupplemental.