Fig. 2: Absolute tree cover changes of North American boreal forests from 2000–2019.
From: Northern expansion is not compensating for southern declines in North American boreal forests
a Tree cover changes based on the MODIS VCF tree cover product of 13,000 sample plots along 69 south-north transects (see Methods). Tree cover change was calculated using Theil-Sen’s slope estimations. The horizontal lines indicate the northern and southern boreal boundary based on Gauthier et al. 20155. Standardised boundary positions were calculated for each sample plot based on its relative position within the boreal boundaries. For better visualisation, tree cover changes are shown as running means along boundary distances with bins of 0.025 (original results in Supplementary Fig. 7). b Mapped tree cover changes across the entire North American boreal forest biome, extending 120 km around the boreal biome boundary (black solid line, based on Gauthier et al. 20155). The dashed line represents the halfway positions between the northern and southern boreal biome boundary (comparable to a standardised boundary distance of 0 in a). For a better visibility, the map is of coarser resolution than the MODIS data set (~1000 m instead of 250 m, rescaling was done through cell aggregation using means).
