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Harvard Forest REU Symposium Abstract 2007

• Title: Fatter Boles, Changing Goals, Native Poles, & Overstory Tolls of Plantation Forests
• Author: Nicole M Mercier (University of Maine)
• Abstract:

  Many of the remaining non-native plantations established in the early days of Harvard Forest will be harvested next winter. A suite of permanent vegetation plots was established throughout the plantations to assess vegetation structure in plantations and predict future dynamics in harvested and early seral habitats. Plantations sampled were established between 1916 and 1944. The specific objectives of this analysis were to determine the long term affects of thinning treatments on overstory structure and to characterize current tree regeneration and understory flora that will in large part determine the future composition of these forests as the overstory is harvested or senesces.
  
  Intermediate stand treatments were carried out in some plantations through the 1940s, and plantation management effectively ceased by the 1960s. The general principles of thinning suggest that stands that have been thinned will allocate wood production to fewer, selected individuals, resulting in higher average stand diameters than unthinned stands. Graphical analyses show that thinned stands may have larger average stand diameters than untreated stands. The goals of Harvard Forest have shifted from demonstrating sustained timber yield to studying ecological dynamics. This may explain the lack of follow up thinning treatments, which if continued could have yielded larger diameter gains.
  
  Plantations are generally considered to have low biodiversity; does species richness differ from native forest and among plantation overstory types? Analysis reveals that plantations have 20-30% less species richness than native forests, and spruce plantations generally have less species richness than pine plantations.
  
  Does understory community composition vary among plantation overstory types? An ordination analysis of understory flora cover generated consistent patterns that led to the conclusion that understory community composition is similar among spruce plantations whereas red pine plantations did not exhibit a strong pattern of similarity, possibly due to the diversity of management histories in the red pine plantations.
  
  Does tree regeneration in the plantations reflect overstory plantation species composition? None of the non-native plantation species seem to be self-sustaining. Red pine seedlings and sapling are rarely found. The spruce regeneration is present only as seedlings, absent from sapling size regeneration. Whether the stands are harvested, the trend indicates that the sites will revert back to native tree species that seed in or emerge from established root systems.

• Research Category: Biodiversity Studies; Conservation and Management; Historical and Retrospective Studies; Physiological Ecology, Population Dynamics, and Species Interactions


• Figures:
Mercierthin.pdf
MedianSpRichnessbyLandUse.pdf
PlantationaDiversity.pdf
PCA.pdf