Vegetation Differences in Neighboring Old Growth and Second Growth Rich Coves in Joyce Kilmer Wilderness Area: A Thirty-two-year Perspective

Abstract

I surveyed vegetation in neighboring old growth and second growth rich coves in the Joyce Kilmer Wilderness Area, North Carolina. This data, combined with data from three previous studies, provide a 32 year perspective of stand structure, species frequencies of occurrence at the 1 m2 scale, and species richness at the 1 m2 scale. I sampled one 0.1 ha plot in each cove. I subdivided each plot into ten 10 m by 10 m modules and sampled percentage cover of all species present in each module, plus stem diameter for woody stems. Additionally, I sampled presence absence in a variety of subplots at scales of 0.01 m2, 0.1 m2, 1 m2, 10 m2, and 100 m2. A cohort of 30-40 cm diameter at breast height Liriodendron tulipifera trees dominated the second growth cove, while the old growth site had a broader mix of species with an inverse J-shape diameter distribution. In both rich coves, the frequencies of occurrence at 1 m2 appeared highly variable for individual species between sample years and distances of 200 m or less.

The four studies provided species richness comparisons at the 1 m2 scale between the old growth and second growth (at ages 16, 35, 39, and 47 years). I concluded that the differences in second growth species richness between studies demonstrated rich cove forest succession. High species richness following disturbance reflected a surge of opportunistic species (age 16). The opportunistic species declined following canopy closure, resulting in significantly lower species richness (age 35). After further stand development, a resurgence of late-succession species increased species richness to equal levels with old growth (age 39 and 47).

Finally, I examined species-area relationships between the two coves, and between these rich coves and the regional average. Arrehnius model (log10 species: log10 area between the scales of 0.1 m2 to 1000 m2) species-area curves indicated no difference in species-area relationships between the two coves. Collectively, these two rich coves had a significantly higher intercept but no difference in regression slope from the regional average. These findings reflect an average rate of species accumulation in the Joyce Kilmer coves, but with higher-than-average species density at all measured scales.