Conservation of a unique community type :analysis of the disturbance history and growth dynamics of a pitch pine (pinus rigida mill.) barren on Wachusett Mountain, Princeton MA

Parker, Sarah L.
Peter Palmiotto, PhD
Department of Environmental Studies
This study analyzed age structure, growth rates and disturbance history of a pitch pine community on Wachusett Mountain in Princeton, Massachusetts. The study site encompassed three small pitch pine openings, together less than one hectare in size, at 500m elevation along the western part of the Mountain. Four 20m² plots and ten nested 1m² subplots were used to characterize the vegetation on the site and tree cores were used to analyze age structure and growth rates. This sit was dominated my Eastern hemlock (Tsuga Canadensis), pitch pine (Pinas rigida Mill.) and red oak (Quercus rubra) in the overstory with blueberry (Vaccinium spp.), black chockeberry (Aronia melanocarpa), and hairgrass (Deschampsia flexuosa) in the understory. Esposed rock, moss and lichen made up a large portion of the ground cover. Sixty-six pitch pines were found within the study site, ranging in age from 20-220 years (mean 78.3 yrs.). Although no synchronous disturbance or release events were found across the community, radial growth data demonstrate that these pitch pines were regularly experiencing abrupt growth decreases and major releases throughout their lifetime. Historical records make no mention of fire on the site, but indicate that grazing may possibly have occurred in the mid-19th century, although the data supporting this is largely circumstantial. The results demonstrated the ability of pitch pine to survive and reproduce on such a harsh site with thin nutrient=poor soils and substantial snow, ice and wind damage. While the specific interactions between pitch pine and hemlock on this site were outside the scope of this study, there was evidence of a subtle shift away from an open pitch pine community to a hemlock dominated forest.

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