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Harvard Forest Symposium Abstract 2008

  • Title: Dwarf Pitch Pine Communities in the Southern Taconics: Race Mountain, Bear Mountain, and “Hill 1914”
  • Primary Author: Glenn Motzkin (University of Massachusetts - Amherst )
  • Additional Authors: David Foster (Harvard Forest); David Orwig (Harvard Forest)
  • Abstract:

    We used a combination of dendroecological, historical, and field studies to examine the long-term history, development, and vegetation dynamics of three dwarf Pinus rigida (pitch pine) locations in the southern Taconic region: “Hill 1914” on the eastern boundary of Mount Everett State Reservation and Race Mountain in southwestern Massachusetts and nearby Bear Mountain in northwestern Connecticut. All three sites supported communities dominated (80 to 98% relative importance) by stunted P. rigida, which apparently persists in the absence of frequent fire because of the harsh site conditions, especially shallow soils and frequent damage from winter storms. Cone serotiny, which is characteristic of dwarf P. rigida communities elsewhere in the eastern U.S., was not observed on any of the summits, consistent with the lack of frequent fire. Race Mountain had the highest density of dwarf P. rigida (1482 stems ha-1), approximately three times the density on Bear Mountain. Hill 1914 had the highest P. rigida basal area (18 m2 ha-1), ~ four times the basal area on Bear Mountain. Interestingly, Bear Mountain had substantially lower densities of dead P. rigida than the other summits, and supported higher P. rigida seedling and sapling densities and contained more upright stems with well-defined leaders. Understory vegetation was similar among the three sites, with several herb and shrub species (Deschampsia flexuosa, Aronia sp., G. baccata, Q. ilicifilolia, and V. angustifolium) common in all plots. Average age of P. rigida was greater on Hill 1914 (111 years) than on Race Mountain (93 years). Although none of the sites was characterized by old-growth P. rigida, Hill 1914 supported the oldest known P. rigida in Massachusetts (228 years old). Based on our experience with pine barrens throughout the northeastern U.S., we consider the complex of dwarf communities on the summits of the southern Taconics to be exemplary and worthy of the most stringent conservation measures. We will continue to examine additional ridgetop communities to place the results of this site into a broader landscape context and to make comparisons with native Pinus resinosa (red pine) forests that have been influenced by fire and other factors.

  • Research Category: Physiological Ecology, Population Dynamics, and Species Interactions