PARENT SESSION
Poster Session #30: Disturbance Ecology II.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Vegetation and disturbance history of a rare dwarf pitch pine community on Mt. Everett, Massachusetts.

Orwig, David^*,1, Motzkin, Glenn¹, Foster, David¹, ¹ Harvard University, Harvard Forest, Petersham, MA

ABSTRACT- Age-structure analyses and historical records of human and natural disturbance were used to investigate a 8 ha dwarf pitch pine (Pinus rigida)-oak community on the summit of Mt. Everett, southwestern Massachusetts. This site was characterized by exposed bedrock, shallow soil depths of 10 to 18 cm, and abundant pitch pine 0.5 to 2.0 m tall. The un-even aged stand included red maple (Acer rubrum), red oak (Quercus rubra), and birch (Betula) species. Pitch pine ranged in age from 12 to 170 years old and exhibited continuous recruitment since the 1830s. Hardwood species established in most decades since 1860, and in higher densities in the 1950s and 1960s. Diameter was a poor predictor of age, as 10-cm diameter trees differed in age by more than 100 years. Many pines exhibited multiple stems, prostrate growth forms, and evidence of terminal branch damage. There was no historical or recent evidence of fire or human impacts in this forest, but wind, snow, and ice damage are dominant disturbance factors on this exposed summit (795 m a.s.l.). Pitch pine radial growth averaged <0.40 mm y^-1, and a few grew only 0.08 to 0.30 mm y^-1. The unusual structure, extremely slow growth, and persistence of dwarf pitch pine in the absence of fire is highly unusual among Northeastern barrens and suggest that harsh edaphic and climatic conditions maintain this unique community.

KEY WORDS: Pinus rigida, Disturbance, Vegetation dynamics