Two decades of change in vegetation in Adirondack spruce-fir, northern hardwood and pine-dominated forests

In 2004 we remeasured trees in 42 permanent vegetation plots that had been established in Adirondack spruce-fir, northern hardwood, and pine-dominated stands in 1984. Over the 20yr interval, live basal area (BA) in red spruce and/or balsam fir-dominated plots decreased by 15%. Blowdown was a major cause of balsam fir, but not red spruce mortality in two plots. Excluding the two blowdown plots, balsam fir live BA increased by 17%, while red spruce live BA decreased by 42% (P < 0.05). There was no significant change in the overall live BA of northern hardwood plots. However, excluding beech, the pooled northern hardwoods showed a significant decrease (P