Natural regeneration processes on post-agricultural land on the clayplain of the Champlain Valley, Vermont USA

Otsuka, Barbara G.
Tom Wessels, MA
Department of Environmental Studies
The conservation community is setting up forest restoration projects on the clayplain of the southern Champlain Valley of Vermont USA. Due to intensive agricultural use, only fragments of forest remain on an area which was 98% forested in pre-settlement times (Lapin 2003). Information on natural successional processes on old-fields which have been abandoned from agricultural use may be used to inform restoration planning. Over one field season a survey of the old-field vegetation at three abandonment ages (25, 40 and 60+ years) was conducted at sites matched for soil type, topography, land-use history, and distance from Lake Champlain with its climate influence. Thirty-eight plots were subjectively sited to capture the range of variability composition and structure. Chronosequence results revealed a succession from a gray dogwood thicket community in the 25-year-old age class, through a shrubland in the 40-year-old age class with three distinct strata, evidencing a mix of old-field or early successional vegetation and some species characteristic of the clayplain forest type, to a young forest in 60 years time, dominated by tree species. The data set was examined using multivariate analysis. Suggested groupings included 25- and 40-year-old complexes, a young forest community at age 60 dominated by red maple (Acer rubrum) with a substantial presence of shagbark hickory (Carya ovata), ash (Fraxinus sp.), and oak (Quercus sp.), and two additional mixed-age communities. Abandonment age and soil moisture yielded the strongest correlation in DCA ordination.

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