Tree height and diameter at breast height were measured annually
for all plots from tree age 6 in 1997 to 19 years in 2010. Stocking,
mean top height, basal area and stem volume were estimated for each
subplot as described previously (Wang et al., 2006). To assess tree nutri-
tional status, samples of current-year foliage were collected in autumn
(March) annually from 1998 from the top third of the crowns of ran-
domly selected trees in each plot. Foliar samples were bulked across