Black spruce needle nitrogen concentration from 1998

We collected black spruce needle from one site located near Fairbanks Ak (S1: 64o52.164? N, 147o51.462? W) in August 1998. The needles were collected from 10 different trees, 5 leafage classes, 3 layers, 2 aspectss, and 3 replicates of each. Nitrogen concentration was measured on these needles. Data analysis indicated that canopy aspect and height did not significantly influence needle concentration, but needle age (F = 555, P < 0.0001) and individual trees within a stand (F = 108, P < 0.0001) combined to explain over 90% of the variation in foliar N.