PARENT SESSION
Poster Session #39: Disturbance Ecology.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall
34
Diversity among floras of shelterwood stands in the Green Mountain National Forest, Vermont.
Wade, Gary1, Sanders, Laurie2, 1 2
ABSTRACT- Forest clearcutting is being replaced in many areas by less intensive harvest methods, and most of this is occurring in secondary stands instead of old growth. Because of the need to know the effects of more common cutting practices on biodiversity in the working forest, we inventoried the vascular flora composition of nine sugar maple-beech-yellow birch stands in the Green Mountain National Forest of Vermont. The abundance of each identified taxon was rated and recorded as "abundant," "frequent," "occasional," "infrequent," or "rare" in each stand. Three stands had been shelterwood cut 11-13 years prior to the study, three were shelterwood cuts 21-24 years of age, and three were mature secondary stands greater than 125 years old. Taxonomic richness of the stands (8-13 ha) ranged 108-232. The young stands were significantly (alpha = 0.05) richer than the old stands. The numbers of exotic taxa were greatest in two young stands and one mid-aged stand in which commercial seed mixes had been used to restore the former roads, landings, and other disturbed areas. Pair-wise comparisons of stand compositions using Sorenson's index of similarity and Spearman's rank correlation of taxa abundance showed that the young stands were compositionally least similar to the old stands. Homogeneity of floras was highest in the old stands and lowest among the mid-age stands. No old stand core taxa were missing from the young stands and one was missing from the mid-age stands, but the distribution of taxa among abundance classes was skewed toward infrequent and rare in the cut stands.
KEY WORDS: inventory, disturbance, silviculture, forest