Presettlement and Present Forest Vegetation in Northern Vermont with Special Reference to Chittenden County

Abstract

The trees recorded in the original land surveys of the township lines of northern Vermont (ca. 1783-1787) and the lotting surveys within the townships of Chittenden Co. (ca. 1763-1802) have been used to study the composition and map the distribution of the presettlement forests. Forest composition was measured in 1962 at 193 points in Chittenden Co. where original survey data was available, and was compared to presettlement composition. Several general regions of forest were delimited in northern Vermont based primarily on the distribution of pine, hemlock, spruce and fir. A gradient of relative abundance of these conifer species was evident from pine in the Champlain Valley and Connecticut River Valley to hemlock on the midslope uplands and fir and spruce in the mountains and northeastern highlands of the state. A map of probable presettlement vegetation of Chittenden Co. was prepared based on geographical distribution of species of witness trees, elevation, soil-substrate types, topography, and early historical records. The outstanding feature of the presettlement forest was the great abundance of beech. Beech ranged from more than 60% of the species composition on the upland midelevation soils in Chittenden Co. to 13% on the spruce-fir-dominated highlands in northeastern Vermont. Average beech abundance in hardwood forests was about 40%, which is in accord with the findings of other studies based on witness trees in New York, Pennsylvania and north central states. Beech made up over 40% of the trees in the presettlement forest, but in 1962 it comprised only 3-5%. This is probably due to the slow but persistent pattern of regeneration of beech in stands by root sprouts and the formation of clones resulting in its maximum development in old-age, undisturbed forests. Comparison of pre-settlement and present forest composition indicated no outstanding changes in the presence or absence of species within soil-substrate types or elevation belts, but there was a distinctive overall increase in the importance of pine, hardhack and poplar in the present forests on the intermediate elevations which reflects the stages of secondary succession on much abandoned farmland throughout Chittenden Co. Surveyor bias for selection of some species over others as witness trees was investigated. A study of stake-to-tree distances which could reveal possible selection due to greater distances to those species which were being favored did not indicate any bias and the surveyors apparently took the tree nearest the stake which met whatever diameter and state-of-vigor requirements the surveyors were using. The number of witness trees per unit area in Chittenden Co. was similar to the number used in studies in other areas in the north central states. 153 1 The work reported in this paper was done as an M.S. thesis at the Botany Department, University of Vermont, Burlington. This content downloaded from 157.55.39.104 on Mon, 20 Jun 2016 05:52:35 UTC All use subject to http://about.jstor.org/terms 154 THE AMERICAN MIDLAND NATURALIST 85(1)