Vermont Agriculture

Abstract:

The Appalachian extensions of the boreal forest or taiga, dominated by balsam fir, red spruce, and white birch extends down the slop of the green mountains to about 2,600 ft, where it merges with the Eastern Deciduous Forest dominated by sugar maple, beech, and yellow birch. These two forest formations occur as well developed horizontal bands on the mountains with a distinctive tension zone forest between them. In this mid-slope forest the species of neither the deciduous nor boreal forest are able to form well-developed long lived stands

The contact between the deciduous and boreal forest is climatically, not edaphically, controlled. The current vegetation and soil development is the result of long term effects of a vertical climatic discontinuity expressed as a nonlinear decline in the length of the frost-free period across the mid-slope transitional forest and as a marked increase in the frequency of the cloud base at and above ca 792 m. This results in increased moisture from fog drip and frequent occurrence of hoar frost in winter. The sharp decrease in the length of the growing season, together with the marked changes in icing and atmospheric moisture conditions, limits the upward extension of the beech-maple forest.

Key words:

Vermont; Green Mountains; forest; climate; soils; zonation

Introduction

Vegetation has been used as a tool to assess the environmental condition of forest land. Numerous studies have demonstrated the effectiveness of vegetation in providing insight into the ecological meaning of physiography and soils that influence its composition, size, and structure. Ground-cover vegetation (shrubs, herbs, and ferns) in particular has been used extensively as an indicator of moisture and nutrient condition of sites. Such species often have narrower amplitudes of occurrence over moisture and nutrient gradients than species relating to trees, reach "dynamic steady state" more quickly than arboreal species and, most species being clonal or perennial, are typically less affected by disturbances than arboreal species, i.e. not eliminated from sites after severe disturbance. Although the use of vegetation to assess the habitat condition of forest land is not without limitation, approaches have been developed that integrate the occurrence and

Introduction: The Green Mountains are the outstanding geomorphological features of the State of Vermont and one of major mountain ranges of the northeastern United States. They are physically quite different from the adjacent mountain ranges (White, Adirondack, and Catskill Mountains) in that the latter are complexly clustered in irregular masses while the Green Mountains are an elongated ridge. Thus the Green Mountains have a more simplified environment and possibly a more comprehensible pattern of forest development.

Findings

The forest of Vermont extends northward from [maple/ beech/birch] forests to the south, across the central mountains of the New England Plateau, and into forests dominated by spruce/fir. The importance of Vermont's natural resource varies with the abundance and character of its forests. A common characteristic that helps describe the landscape is the distribution of forest types or forests type groups. Forest-type groups vary in distribution throughout the state. Their distribution depends on factors such as terrain position, soil, and climate. Northern hardwoods, specifically, the northern hardwoods forest-type groups, accounts for 67 percent of Vermont's 4,628,900 acres of forest land., the next most abundant forest-type groups are white/red pine and spruce/fir, which accounts for 11 and 10 percent of the states forest land, respectively. Each forest-type group helps define the character of forests that occur across Vermont's' mountains and Valleys. For example, the oak/hickory forest-type group is far more important in the southern counties, while the spruce/fir group is more common primarily in the northern countries. Over the years, different criteria have been pressed into service to better classify the forest landscape. Biophysical regions were proposed in the early 1990's and refined in 1995.

The Green Mountain State itself is a rich tapestry of biological diversity. Vermont contains a diverse mixture of these regions which, contain blends of these forest-type groups. There are eight biophysical regions have been identified; Taconic Mountains, Vermont Valley, Southern Green mountains, Southern Vermont Piedmont that stretch across the States southern level, Champlain Valley, Northern Green Mountains, Northern Vermont Piedmont, and Northeastern highlands, which envelope nearly all of the 10 northern counties as shown in the graph below.

Northern Hardwoods dominate over every region of Vermont, except for the two Piedmont regions where they only cover roughly about half. The northern Vermont piedmont and northeastern Highlands also contain substantial amounts of spruce/fir and aspen/birch, while the oak/hickory and oak/pine forest-type groups account for about 52-12 million acres, respectively, in the southern Piedmont.

The hardwood species outnumber the softwood species buy a ratio of 2 to 1 in the forests of Vermont. Sugar maple (Acer saccharum) is the most commonly occurring tree species, reaching concentrations up to 50 percent in the Northern Piedmont region and 20 to 50 percent in the Northern Green Mountains and Champlain Valley. Red maple (Acer rubrum) also is dominant throughout Vermont, specifically in the southern area of Vermont. Paper Birch (Betula papyrifera) extends primarily along the entire range of the Green Mountains, while Yellow Birch (Betula alleghaniensis) is found mostly along the same range but at higher elevations. Hemlock (Tsuga Canadensis) is the leading softwood species and is concentrated in the southwestern corner of the state, Northern Green Mountains, and north of Lake Champlain. This species often grows in conjunction with eastern white pine, which is found primarily along the Connecticut River in southern Vermont. Balsam fir (Abies balsamea) is distributed primarily in the Northeastern Highlands and Northern Piedmont, while spruce is common throughout the Southern Green Mountains. Other common tree species in Vermont also includes ash, aspen, beech (Fagus grandifolia), and northern red oak. Of these species, only beech is found in concentrations as high as 20 to 50 percent.

During the 1980's, high rates of spruce decline were observed across New