The Tripartite Greening of Northern Quebec, Canada: 1986-2010
McManus, K.M., Morton, D.C., Masek, J.G., Wang, D., Sexton, J.O., Nagol, J.R., Ropars, P. and Boudreau, S. 2012. Satellite-based evidence for shrub and graminoid tundra expansion in northern Quebec from 1986-2010. Global Change Biology 18: 2313-2323.
Results indicate that "30% of the observable (cloud-free) land area experienced a significant (P < 0.05) positive trend in the Normalized Difference Vegetation Index (NDVI)," with low shrub and graminoid (grass-like) tundra contributing "preferentially to the greening trend." Across the entire transect, for example, they report that "the area-averaged LAI increase was ~0.2 during 1986-2010," while "a higher area-averaged LAI change (~0.3) within the shrub-tundra portion of the transect represents a 20-60% relative increase in LAI during the last two decades." This "observed association between shrub cover types and increased NDVI," in the words of the eight scientists involved in the study, "is generally consistent with the concept that woody plants can take advantage of warmer conditions and grow more vigorously."