Summary
Forty-four sites in the Harvard Forest were assessed with respect to overall physiognomy of the vegetation, coverabundance estimates of the woody species and several environmental variables. The data were subjected to cluster analysis and ordination. In the latter, principal component analysis produced more acceptable and clear-cut results than a Bray-Curtis ordination. The major gradient of vegetational variation is due to disturbance, followed by a moisture gradient and what appears to be a soil texture and soil depth gradient. The high proportion of variance which is not associated with common trends in the vegetation suggests that random variation is an important factor in the composition of the forest. The data obtained from the rapid estimates of physiognomy and species composition, and the methods used for analysing them, are considered to be satisfactory. The success of the approach lies in how well the number of sites used represents the study area as a whole.
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Nomenclature follows ‘Gleason. H.A. and A. Cronquist. 1963. Manual of vascular plants of northeastern United States and adjacent Canada. D. Van Nostrand Co. Inc., Princeton, N.J. 810 p.’
I thank Prof. H. Raup, Dr. E. Gould and Mr. W. Lyford for discussion and comments on the results of this study, and Dr. J. M. A. Swan for criticizing the initial manuscript.
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Walker, B.H. Vegetation — Site relationships in the Harvard forest. Plant Ecol 29, 169–178 (1975). https://doi.org/10.1007/BF02390008
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DOI: https://doi.org/10.1007/BF02390008