Land Use and Forest Dynamics at Harvard Forest

• Investigators: Arthur Allen, David Foster, Glenn Motzkin, Paul Wilson
• Contact: Glenn Motzkin
• Start date: 1937-01-01
• End date: 1995-12-31
• Location: Prospect Hill Tract (Harvard Forest)
• Latitude: +42.53 to +42.55
• Longitude: -72.20 to -72.17
• Elevation: 280 to 420 meters
• Taxa:
• Keywords: disturbance, land-use history, soil
• Release date: 2003
• EML version: knb-lter-hfr.15.2
• Revisions:
• Abstract:

  Modern vegetation patterns have developed as a result of species response to environmental gradients, disturbance history, and biotic interactions. However, the relative importance of environmental versus historical factors in determining modern species distributions may differ from site to site and may change with increasing time since disturbance. In addition, life-forms may differ in their response to environmental versus historical disturbance gradients. In the current study, we relate vegetation patterns across the Prospect Hill Tract of Harvard Forest to variability in edaphic factors and disturbance histories.

  Modern species distribution patterns are related to both edaphic and disturbance gradients. Although species respond individualistically to edaphic and disturbance gradients, land-use history, soil drainage, and C:N ratio are good predictors of the distribution of many species. In contrast, 1938 hurricane damage is less important. Vascular species richness is related to historical land-use, with fewer species in historical woodlots than on former agricultural sites. This is contrary to what has been reported from several other studies, and may reflect the dominance of historical woodlots in the study area by hemlock, a species that creates environmental (i.e. light and soil) conditions that are unsuitable for many species. Historical land-use does not appear to influence bryophyte species richness, although the distributions of several species do follow patterns of land-use. Species richness also varies according to soil drainage, with higher bryophyte, herb, and shrub richness and lower overstory and understory tree richness on wetter sites.

• Methods:

  Vascular vegetation was sampled on 269 1/8th acre (22.5 x 22.5 m) plots and bryophytes were sampled on a subset of 105 plots. Many of the plots had been previously sampled in 1937 as part of the Harvard Forest inventory. A comprehensive data set of edaphic variables developed for these plots includes soil drainage, texture, organic matter content, bulk density, pH, CEC, base saturation, cation concentrations, and C:N ratio. Field and archival records were used to summarize disturbance histories for each plot, including historical land-use, date of abandonment, 1938 hurricane damage, and fire and forest management history.

• Use:

  This dataset is released to the public and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement. For more information on LTER Network data access and use policies, please see: http://www.lternet.edu/data/netpolicy.html.

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