NDVI
Standardized mean site-level shoot length growth was positively correlated with late summer (July-August) NDVI (r=0.44, p<0.01, Fig. 6a) as well as NDVImax (r=0.40, p<0.05). There was a weak link between standardized branch initiation and NDVImax (r=0.26, p<0.1; Fig. 6b). There were no negative correlations between standardized branch mortality frequency and NDVI in the research area. There was a slight positive trend in late summer NDVI over the period 1981-2013 (r=0.24, p<0.1; Fig. 6a), but not in NDVImax.
Late summer NDVI and NDVImax were positively related to summer and, notably, winter temperatures (Table 3). Furthermore, there were positive relationships between late summer NDVI and spring precipitation sums, and weakly, late winter precipitation sums (Table 3).