Overview of current status of Prospect Hill Stewardship Project

 

 

Vegetation Inventory Report-Prospect Hill Pasture for the Dummerston Conservation Commission by Chris Cabot and Jess Wheeler, May 2008

 

If you would like a copy of this report complete with photos, maps, etc., contact mary Ellen Copeland at (802) 257-0012

 

Acknowledgements
We would like to thank the Dummerston Conservation Commission for the opportunity to complete this inventory on town land; John Evans, of the Dummerston Trails Committee, for his time during an initial visit to the parcel and land use history insights; and Jeff Nugent, of the Windham Regional Commission, for access to GIS data. Professor Peter Palmiotto provided valuable direction throughout the project.

Overview and Purpose
This vegetation assessment describes a 35-acre parcel known as the Prospect Hill Pasture, which is owned by the town of Dummerston, Vermont (Figure 1). The parcel is located northwest of Dummerston Center and is a popular recreation area for hiking and snowshoeing.
The town acquired the land in 1974 from the estate of Edith R. Bradley, who had bequeathed the land in her will. Ms. Bradley’s parents had owned the land previously and had used the parcel as a summer pasture for their dairy cows until 1943 when they conveyed the land to their two daughters. This is evident on the parcel as many white pine trees, a species known to be an initial colonizer of abandoned pasture, appear to be approximately 65 years old.
Currently, the Dummerston Nature Reserve and Trails Committee, which is a working group of the Putney Mountain Association, maintains a trail system on a portion of the land. Efforts are underway to link this trail system to others near Windmill Hill and Putney Mountain.
The land is part of a larger group of connected parcels which are, or will soon be, protected under conservation easements. The approximate total for all of the protected parcels is 400 connected acres, which is a great benefit to local biodiversity.

The goals of this inventory include the description of forest community composition and structure.  The Dummerston Conservation Commission and John Evans, Chair of the Trails Committee, are the primary stakeholders, and they are interested in the following: stand density, species diversity, size and age of trees, soil types, percentage of land in distinct community types, as well as other notable land features or evidence of wildlife.  These known ecological factors contribute to the overall understanding of the forest community of Prospect Hill and could serve as a reference for any future conservation considerations.  The local 5th grade class currently maintains a section of the trail and provides an interpretive map at the trailhead for hikers.  Our findings and maps may be useful for the school group.

Figure 1. Town parcel and trails of Prospect Hill Pasture, Dummerston, Vermont.

Description of Study Area
The vegetation inventory occurred on 35 acres of town owned property on Prospect Hill in Dummerston, Vermont. The land straddles the summit of Prospect Hill with water on the western side draining into Basin 11 (West – Williams – Saxtons Rivers) while the eastern slopes drain into Basin 13 (Lower Connecticut – Mill  Brook).  There are no wetlands or perennial streams on this site, but one area on the eastern side contains an intermittent stream. There is an old stone wall and fence defining the eastern property line. The eastern slope of Prospect Hill contains a variety of tree and shrub species typical of mid-succession hardwood forests found in the Northeast. The summit of Prospect Hill, which has been routinely cut, is mostly clear of trees and contains shrub and groundcover adapted to warm and dry conditions. The southwestern corner of the property is steep with a southern aspect and was heavily cut in order to open the view from the summit. The remainder of the western side of the parcel not cut in the most recent logging operation consists primarily of white pine.

Methods
In order to describe the plant communities and dominant species within them, a multiple fixed plot sampling method was conducted on the parcel. Using aerial photographs in the office at Antioch University New England, in Keene, New Hampshire, we delineated three forest community types within the 35-acre parcel. Stratified-random sample plots were selected using Arc-GIS, in each of the three communities. Thirty random plots were stratified according to the area of each of the pre-determined communities. Using this method, the west community had 10 points (33.2% of the total area); the summit community had 3 points (9.3%); and east community had 17 points (57.5%). When in the field, a section of the west community was found to have been heavily logged. Due to the drastic alteration of this forest, we delineated it as a fourth community (Figure 2). This viewcut community had five sample plots, which left five in the west community. Sample plots were located in the field using a handheld Garmin 76 GPS unit, which had an average accuracy of ±27.5’ with a range of ±15’ to 74’.  All plots were located at least 49’ (15 meters) away from the edge of a community to decrease sampling of edge conditions.  Circular 1/50th acre plots with a radius of 16.7’ were used to obtain a 1.7% sample of the whole land parcel.
The plots were measured with a tape measure and flagged at four positions along the perimeter.  Trees ≥4 in. dbh within the circle were measured using a scaling stick.  Saplings, considered to be woody stems <4 in. dbh capable of achieving tree size, were tallied by species within a nested subplot with an 8’ radius.  Slope angle and aspect were measured at each plot using a Suunto clinometer and a Suunto MC-2 compass.  Canopy cover and woody shrub cover by species within the 8’ subplot was measured using modified Daubenmire cover classes where Class 1 is equal a range of 1 to 5 and a mean of 2.5 and Class “t” is equal to a range of  <1 to rare and a mean of 0.1. Shrubs were classified as woody stems <1 m in height not capable of achieving tree size.  We also recorded presence or absence of canopy coverage at each sampling point using a densitometer.  Any invasive, rare, or indicator plant species witnessed on the parcel that fell outside of our sampling efforts were noted for conservation implications.
Field data was collected on April 16 and 23, 2008.  Due to time constraints and time of year, no field data was collected about herbaceous species or soils on the parcel, but soil type information was collected from the county soil survey.  Data analyses included basal area per acre by community type and by species, frequency and density by species, relative frequency, relative density, and importance value.  We calculated results using Microsoft Excel and used ArcGIS from ESRI for all maps and some data analysis.

Figure 2. Delineated natural communities for the Prospect Hill Pasture, Dummerston, VT.

Results
The four natural communities varied in vegetation diversity as well as abundance and tree size.  The east community was the most diverse containing 12 tree species while the west had 5 and the viewcut community had 3.  The west had the highest basal area per acre at 266.5 ± 26.8 ft2/ac followed by the east with 135.9 ± 19.5 ft2/ac and the viewcut with 7.0 ± 2.7 ft2/ac. No tree species were recorded in the summit community (Figure 3).

Figure 3.  Basal area per acre by community on Prospect Hill Pasture, Dummerston, VT. Spring 2008.

Basal area of white pine was highest among the west community at 199.5 ft2/ac and was considerably less in the east community at 32.9 ft2/ac.  The highest basal areas in the east were white pine (32.9 ft2/ac), paper birch (23.7 ft2/ac) and black birch (21.6 ft2/ac).  The viewcut community had smaller basal areas per species relative to the east and west community with white pine at 2.8 ft2/ac and black birch at 3.3 ft2/ac (Figure 4).

Figure 4.  Basal area per acre for each tree species by community on Prospect Hill Pasture, Dummerston, VT. Spring 2008.

The mean density of tree stems varied between communities; east (23.5 ± 22.1 stems/ac), west (24.6 ± 51.7 stems/ac), and viewcut (3.8 ± 7.7 stems/ac) (Figure 5).  Density of black birch was the highest of all species in the east at 70.6 stems/ac, followed by hemlock (47.1 stems/ac) and paper birch (47.1 stems/ac).  White pine in the west community had the highest density of all species on the parcel at 180 stems/ac.

Figure 5. Density in stems per acre for tree species by community on Prospect Hill Pasture, Dummerston, VT. Spring 2008.

The most dominant tree species in the east community were black birch, paper birch, and white pine with importance values of 0.20, 0.15, and 0.15, respectively (Figure 6).  The west community was dominated by white pine (0.59), black birch (0.17), and red maple (0.15).  White pine (0.61), black birch (0.26), and beech (0.12) were the only tree species recorded in the viewcut community.

Figure 6. Importance value for tree species by community on Prospect Hill Pasture, Dummerston, VT. Spring 2008.

The east community’s aspect averaged 89° at a slope of 24%.  The summit faced a direction of 202° with a 13% slope while the viewcut faced 226° with a slope of 20%.  The west community had an average aspect of 212° with a slope of 17%.   Canopy cover was recorded at a mean of 97.5% for all of the west and east communities.  The summit and viewcut communities were very exposed with canopy covers of 0 and 0.1%, respectively.
All four communities had some degree of total shrub cover, albeit much less in the west, east and viewcut communities than the summit (Figure 7). The dominant cover of the summit community consisted of blueberry (56.7%) and grass species (33.3%, all taxonomic groups pooled).  The east community contained cover of blueberry (4.7%), invasive honeysuckle (0.88%), and barberry (0.15%).  The younger viewcut community contained a small percentage of blackberry (1.5%) (for the purposes of this inventory, we refer to all species of the Rubus genus as blackberry), blueberry (1%), and honeysuckle (1%).  The west community contained the least abundant shrub layer with small amounts of blueberry (1%), honeysuckle (.02%), and barberry (.02%).

Figure 7.  Percent cover of woody shrub and grass species in each community on Prospect Hill Pasture, Dummerston, VT. Spring 2008.

Average total sapling counts were relatively similar among the viewcut (0.78 saplings/plot), west (0.40 saplings/plot), and east (0.26 saplings/plot) communities.  Both the east and viewcut communities contained an average of 3 beech saplings/plot (Figure 8).  Quaking aspen (2 saplings/plot) and white ash saplings (1.8 saplings/plot) were also common in the viewcut community, while few were present in the east and west communities.

Figure 8. Average sapling density for each community on Prospect Hill Pasture, Dummerston, VT.  Spring 2008.

Soils

The most dominant soil type within the Prospect Hill parcel is Tunbridge-Lyman fine sandy loam with a 25-50% slope, comprising 15.11 acres of the 35 total acres (Figure 9).  All the soil types on Prospect Hill provide good habitat for hardwood and coniferous trees and herbaceous plants, but the soil type which underlies the majority of the viewcut community, Tunbridge-Lyman fine sandy loam with a 25-50% slope, is noted to have a severe erosion hazard (Table 1).

Figure 9. Soil types and natural community delineation of Prospect Hill Pasture, Dummerston, Vermont.

Table 1.  Soils associated with the 35-acre Prospect Hill Pasture, Dummerston, Vermont.
Management Concerns    Wildlife Habitat    Productivity
Soil
Code
Soil Name
Slope
Acreage
Erosion Hazard1
Wind Throw2    Hardwood & Coniferous Tree Habitat    Herbaceous Plant Habitat
Species
Site Index3
20C    Tunbridge-Lyman fine     8-15%    5.67    slight    moderate    Good    Good    red spruce    50
sandy loam                            sugar maple    60
yellow birch    55
white spruce    55
white ash    65
20D    Tunbridge-Lyman fine     15-25%    13.99    moderate    moderate    Good    Good    red spruce    50
sandy loam                            sugar maple    60
yellow birch    55
white spruce    55
white ash    65
20E    Tunbridge- Lyman fine     25-50%    15.11    severe    moderate    Good    Good    red spruce    50
sandy loam                            sugar maple    60
yellow birch    55
white spruce    55
white ash    65
63D    Berkshire-Tunbridge     8-15%    0.18    moderate    slight/moderate    Good    Good    red spruce    50
fine sandy loam                            sugar maple    60
yellow birch    55
white spruce    55
white ash    65
1Erosion Hazard – The probability that erosion can occur as a result of site preparation or cutting
Slight – no particular measures need to be taken to prevent erosion under normal conditions
Moderate – erosion control measures are needed for silviculture activities
Severe – special precautions are necessary to control erosion in most silviculture activities
2Wind Throw – The likelihood that trees will be uprooted by the wind
Slight  – no trees are normally uprooted by the wind
Moderate – moderate or strong winds occasionally blow uproot  trees when soil is wet
Severe –  moderate or strong winds may blow down many trees when soil is wet
3Site Index – Average height in feet that a dominant or co-dominant tree can reach in an arbitrary, relative  number of years
Source: USDA Soil Conservation Service. 1987. In cooperation with Vermont Agricultural Experiment Station and Vermont Agency of Environmental Conservation. Soil survey of Windham County, VT.
Discussion
The four communities vary in species composition and abundance on Prospect Hill in Dummerston.  Each community is unique in its state of succession and significance to the town-owned land.
The east community, the largest of the four communities comprising 57% of total parcel area and 20.1 acres, contains a diverse assemblage of hardwood and coniferous trees which imparts multiple characteristics of the landscape.  As most of the canopy trees are approximately 60 to 70 years old, this relatively young to middle aged forest allows for an expression of transitional vegetation communities.  This mid-succession forest contains an abundance of white pine, black birch, paper birch, and sugar maple trees. Cumulatively, they are representative of a northern hardwood forest (Thompson & Sorenson 2005).  The high species richness within the east community is likely due to variability in topography and substrate.  The presence of sugar maple, white ash, and hop-hornbeam are indicators of nutrient rich sites (Wessels, 1997) (Figure 7).  Black birch, paper birch, quaking and bigtooth aspen occurring on the northeast slope are likely due to past tree falls which exposed soil and created suitable growing habitat for these small seeded trees. This is evident by the presence of many pits and mounds on the slope (Figure 8).  It is important to note that yellow birch and red oak, including a large, 41” dbh  specimen (Figure 9), are present in the east community though all fell outside of our plot locations.
The west community, 8.5 acres, is most likely of similar age compared to the east, judging from historical data, yet the tree composition is different.  The land faces in a southwesterly aspect, which provides warmer and drier site conditions.  The trees closely resemble a mid-succession stage of a white pine – northern hardwood forest in which, according to NatureServe 2004, white pine, sugar maple, and striped maple are dominant tree species (Thompson & Sorenson 2005). White pine trees dominate this community with black birch, red maple, and few other species also present. We also observed striped maple saplings within the community that missed sampling plots.
The stand of white pines appears to be of even age, suggesting further that this community became established soon after pasture abandonment, as it grows well in clearings as a pioneer species (Wessels 1997). Depending on the effects of beech bark disease, this community may contain more shade tolerant beech trees in the future as there are many beech saplings underneath the approximately 70’ tall conifer trees.  This community may be the most valuable, commercially, with large stands of white pine.
The viewcut community, 3.1 acres, is the youngest community of the four showing species common to early succession such as quaking aspen and white pine. Small white pine saplings approximately nine years old were observed growing amongst the logs, indicating a cut just over ten years ago.  It most likely looked like the west community, as it has similar aspect and exposure and many downed white pine trees.  After the cut, light exposure increased at ground level, providing optimal conditions for pioneer species such as white pine and aspen (Figure 10).  The trees and beech saplings counted in this community are likely relicts from before the cut as they are older than ten years.  This community has some blackberry, blueberry, honeysuckle, and buckthorn growing in the woody shrub layer.  These shrubs will likely thrive for approximately the next decade, but without further management, they will likely be overtopped by taller tree species.
The presence of downed, woody material from the cut may present a physical barrier which deters deer from browsing in the area. This will help maintain a diverse forest rather than one selectively browsed by the deer.  As this community has been recently disturbed, it does not have a designated natural community name; however, it likely resembled a white pine – Northern Hardwood Forest similar to the west community.
The summit community, 3.2 acres, consisted almost entirely of shrubs and groundcover with a few small black cherry trees and a small patch of staghorn sumac.  This community is likely the most visited by hikers for the stunning views to the east, south, and west (Figure 11).  The summit community itself has been managed by cutting trees to preserve the vistas, which was the motivation for the cutting on the viewcut community.  This area is kept in an indefinite state of early succession, where it would otherwise grow to become more like a Northern Hardwood Forest.  The blueberry and juniper growing on this unique hilltop community indicate site conditions are acidic and dry with course substrate (Wessels 1997). This open space provides habitat for herbaceous groundcover, small rodents and mammals such as the New England cottontail, various birds potentially including woodcock, turkey, and cedar waxwing, and American goldfinch, but it also contains a high frequency of invasive plant species relative to the remainder of the parcel.

Recommendations
This inventory of the vegetation may be useful for any future conservation considerations.  As the east community contains the highest number of native tree species, care should be taken to protect the integrity of the area.  The soil of much of the west community is similar to that of the east, so despite the current dominance of white pine, it is likely to develop into a similar forest in terms of species richness over time.  If the town decides to harvest any trees in the west or the east communities, we would recommend a more thorough timber cruise and assessment of ecological impacts.  We found no presence of rare or endangered species, but before this is ruled out, we recommend a thorough inventory of the herbaceous groundcover for any ephemeral species.

Figure 7.  Hop-hornbeam and sugar maple growing in the east community on Prospect Hill Pasture, Dummerston, VT.  April, 2008.

Figure 8  Aspen and paper birch growing amongst pits and mounds on Prospect Hill, Dummerston, VT.  April, 2008.

Figure 9.  Large red oak (41” diameter) pasture tree growing on
the east community, Prospect Hill, Dummerston, VT. April, 2008.

Figure 10.  Looking south over the viewcut community, on the western slope of Prospect Hill, Dummerston, VT.  April, 2008.

Figure 11.  A western view from the summit of Prospect Hill, Dummerston, VT.  April, 2008.
References

Evans, John. Personal Communication. 3 March 2008.

Thompson, E. H. and Sorenson, E. R. 2005. A Guide to the Natural Communities of Vermont. Vermont Department of Fish and Wildlife and The Nature Conservancy.

Wessels, Tom. 1997. Reading the Forested Landscape: A Natural History of New England. The Countryman Press. Woodstock, VT.

U.S.D.A. Soil Conservation Service. 1987. Soil Survey of Windham County, Vermont. Vermont Agricultural Experiment Station and Vermont Agency of Environmental Conservation.