Friends of Wachusett Mountain is a non-profit group dedicated to conservation,
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Old-Growth Forest
David A. Orwig is a Forest Ecologist with Harvard Forest, Harvard University in Petersham, Massachusetts. His research interests encompass all aspects of forest ecology, with particular emphasis on old-growth forest dynamics, dendroecology, and the role of land use history and disturbance on forest structure and composition. These approaches have recently been used to examine forest damage, environmental changes, and related ecosystem processes associated with hemlock woolly adelgid outbreaks in New England hemlock forests.*
Variations in old-growth structure and definitions: Forest dynamics on Wachusett Mountain, Massachusetts
DAVID A. ORWIG1, CHARLES V. COGBILL2, DAVID R. FOSTER1, AND JOHN F. O'KEEFE1
1Harvard University, Harvard Forest, P.O. Box 68, Petersham, Massachusetts 01366 USA
2Plainfield, Vermont 05667 USA
Abstract. One of the largest old-growth forests in southern New England was recently "discovered" on the exposed upper slopes of Wachusett Mountain, Massachusetts, a heavily used recreational area located < 80 km (< 50 miles) from Boston. We analyzed historical records, dendroecological data, vegetation, and coarse woody debris to characterize the dynamics and development of four major old-growth stands on the mountain and explored the potential factors enabling these forests to survive and elude recognition as old-growth forests for > 150 yr. Historical data suggest that most of the area's forests were composed of a mixture of Quercus rubra and northern hardwood species. Species abundances and recruitment dynamics in the four stands exhibit highly variable spatial and temporal patterns across sites that differ in aspect and exposure. Three uneven-aged hardwood stands contain Quercus rubra in the largest size classes, various amounts of Fagus grandifolia, Acer, and Betula species in the middle size classes, and dense thickets of several shrub species in the small size classes. Several of a set of randomly aged individuals of Q. rubra, B. lenta, and B. alleghaniensis are at or very near the maximum longevity known for these species. A Tsuga canadensis stand contains unimodal size and age distributions, with trees < 60-cm dbh and 100–300 yr old. Quercus rubra recruitment occurred on all sites from the 1600s through the early 1800s, when it dropped precipitously on most sites and was replaced by either Tsuga or Acer and Betula species. These recruitment changes were apparently driven by changes in disturbance regime over the last two centuries, from fire in the early record to hurricanes (1815 and 1938), and more recently, frequent wind, ice, and snow damage but no fire. Asynchronous tree-ring releases and suppression and relatively low amounts of coarse woody debris corroborate this interpretation. Chronic canopy damage produced short-statured and unusually gnarled trees, which gave the forest unusual resistance to severe winds from hurricanes, discouraged logging, and prevented the recognition of the forest's old-growth status despite its heavy recreational use.
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Orwig, D. A., C. V. Cogbill, D. R. Foster and J. F. O'Keefe. 2001. Variations in old-growth structure and definitions: Forest dynamics on Wachusett Mountain, Massachusetts. Ecological Applications 11(2):437–452.
An evaluation of the western slope forests of Wachusett Mountain
DAVID A. ORWIG
Harvard Forest, Harvard University, Petersham, MA 01366
Introduction. Recently it has been brought to the attention of the Massachusetts Department of Conservation and Recreation (DCR) that the western slopes of Wachusett Mountain may contain previously unrecognized old-growth forests. The area in question contains primarily hemlock-dominated forests located between the Up Summit Road and West Road, south of the West Side Trail (C. Pernaa, personal communication). Because these forests are located outside of the original Administrative Boundary of contiguous old-growth forest (cf. Foster et al. 1996, 1997; Orwig et al. 2001), detailed vegetation and tree-core sampling was conducted in an effort to document their old-growth status. Extensive reconnaissance of the western slopes of Wachusett Mountain was used to determine whether they meet DCR's accepted definition of old-growth forest. Methods previously used on Wachusett Mountain were implemented to: 1) investigate the structural and compositional attributes of forest stands in this area, 2) develop descriptions of stand age-structure, growth history, and dynamics of these forests, and 3) provide a map delineating all areas investigated in this study.
Click the report title below to download the PDF
Orwig, D. 2004. An evaluation of the western slope forests of Wachusett Mountain. Report submitted to the Massachusetts Department of Conservation and Recreation, Commonwealth of Massachusetts.
* Excerpted from David A. Orwig's profile at Harvard Forest.
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