Global tree cover data (treecover2010) are per pixel estimates of circa 2010 percent maximum (peak of growing season) tree canopy cover derived from cloud-free annual growing season composite Landsat 7 ETM+ data. A regression tree model estimating per pixel percent tree canopy cover was applied to annual composites from 2000 to 2012 inclusive (Hansen and others, 2013). Data gaps and noise from individual years were replaced using multi-year median values. First, a median from annual tree canopy cover values from 2009-2011 was used to estimate 2010 tree cover. For pixels still lacking an estimate, the median calculation was expanded to include tree cover values from 2008-2011, then from 2008-2012. Any remaining gaps were filled with tree canopy cover values derived from a regression tree model using all growing season Landsat ETM+ data as inputs. The resulting layer represents estimated maximum tree canopy cover per pixel, 1-100% for the year 2010 in integer values (1-100).
Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A.,
Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A., Egorov, A., Chini, L.,
Justice, C.O., and Townshend, J.R.G., 2013, High-Resolution Global Maps of 21st-Century
Forest Cover Change: Science, v. 342, no. 6160, p. 850-853,
at
http://www.sciencemag.org/content/342/6160/850.abstract.
University of Maryland, Department of Geographical Sciences and USGS; use is free to all if acknowledgement is made.
[ https://landcover.usgs.gov/glc/TreeCoverDescriptionAndDownloads.php ]