Trip Report:

Reconnaissance Assessment of White-tailed Deer Impacts in the Area of Tadmuck Swamp, Westford, Massachusetts

May 16, 2014

Thomas J. Rawinski

Botanist Northeastern Area State and Private Forestry USDA Forest Service Durham, New Hampshire ([email protected])

A buck rub on a sapling.

At the request of Mr. Al Prescott, Chair of Westford’s Hunting Policy Committee, I visited the town-owned property known as Tadmuck Swamp to evaluate current levels of white-tailed deer impact in the forests there (Figure 1). I visited the site on April 1 and April 22, 2014. Because herbaceous plants were mostly dormant in April, the focus was on trees, shrubs and general forest condition. Herein I report on my findings.

The property is a mosaic of landforms and plant communities. Oak forest prevails on the esker ridges (Figure 2). White pine is locally abundant on the level terrain (Figure 3). Wetlands include vernal pools, small dug-out ponds, red maple swamp and the natural wonder known as Mystery Spring. The surficial geology is mostly sand and gravel of glacial origin. Soils are nutrient-poor, as reflected by the black huckleberry and lowbush blueberry in much of the understory.

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Figure 1. Location of Tadmuck Swamp, north of Interstate 495 and east of Tadmuck Road.

Figure 2. Oak forest of the esker ridge. 2

Figure 3. White pine and oaks dominate on more level terrain. Notice the open nature of the understory vegetation.

Deer impacts are never uniform – they vary across the landscape. Impacts tend to be greatest where food is plentiful and where human activity is minimal. Impacts also reflect the seasonal movement patterns of deer. At Tadmuck, an abundance of pellet groups in the pine forest suggests that the animals spent an inordinate amount of time in those sheltered areas during the winter (Figure 4). Deer sign at Tadmuck seems to increase with distance away from the heavily used hiking trail of the esker. Even still, at night, the deer aren’t shy about visiting back yards and walking up patio steps to browse ornamental arborvitaes (Figure 5).

Figure 4. A pellet group at Tadmuck Swamp.

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Figure 5. Deer-browsed arborvitaes, as viewed from the hiking trail at Tadmuck Swamp.

Because of shade and nutrient-poor soils, palatable woody browse is rather scarce at Tadmuck. Preferred species such as white oak, red maple, black gum, alternate-leaved dogwood, wild raisin and maple-leaf viburnum show considerable browse damage. The undergrowth is clearly being trimmed and suppressed by deer. I had to conclude that deer were preventing the regeneration of deciduous tree species and several shrub species in the interior forests. One indication of this is the simplified structure of the forest vegetation. Walking is easy where the undergrowth of saplings and shrubs have been reduced in stature.

One of the most abundant plants at Tadmuck is the invasive shrub, glossy buckthorn. Glossy buckthorn tends to be a low-preference species. However, I observed several areas where it was being suppressed by deer-browsing. Three other low-preference species showed evidence of browse damage, namely American chestnut (Figure 6), white pine (Figure 7) and sheep laurel (Figure 8). For the most part, American chestnut sprouts are still able to grow above the reach of the deer, and browse damage to white pine is still rare and inconsequential. But if the deer density continues to increase, both of these low-preference tree species will be browsed to a greater extent.

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Figure 6. Browse damage to a sprout of American chestnut.

Figure 7. Browse damage to white pine.

Figure 8. Browse damage to sheep laurel, a low-preference evergreen shrub.

5 People tend to view forests in static terms. But forests are ever-changing, slowly and imperceptibly. Only in hindsight do we realize how dramatically things can change, especially when deer density increases. As recently as 10 to 20 years ago, many forests in eastern Massachusetts showed little evidence of deer damage. Today, such damage is becoming the norm. If little is done to control the growing deer herd, these forests will be all the worse 10 to 20 years from now.

Yes, there is every indication that deer herds will continue to grow in eastern Massachusetts. The white-tailed deer is a prolific and adaptable prey species endowed with acute senses and keen survival instincts. For thousands of years, humans, wolves, cougars, bears and other predators preyed heavily on whitetails. But now, with limited predation, deer populations are skyrocketing, degrading their own habitats and causing other problems. Hunting, vehicle collisions and wild predation remove some animals from Westford’s deer population (Figure 9), but hardly enough to compensate for the reproductive potential of these animals. Their populations will continue to grow in Westford, and elsewhere in eastern Massachusetts, unless humans assume a more active role in deer management.

Figure 9. One of many coyote scats observed at Tadmuck Swamp.

Thousands of communities across the U.S. are facing this same challenge, with some being more successful than others. In Massachusetts, Medfield, Dover, Framingham, Sudbury, Westborough, Andover and Weston are some of the towns that have re-introduced deer hunting to conservation lands, recognizing the crucial importance in controlling deer populations. These communities recognize that a deer harvested by a hunter, and put to use feeding a family, is preferable to seeing one die wastefully in a collision with a vehicle. There is now a broader acceptance and appreciation of hunters in these communities.

A crisis situation with deer does not yet exist in Westford, but an opportunity exists to be proactive in addressing this growing threat. Myriad communities wish they had taken decisive action sooner. 6 Appendix 1. Some plants of the Tadmuck Swamp area.

Trees Aceraceae (Maple Family) Lauraceae (Laurel Family) Acer rubrum Red Maple Lindera benzoin Spicebush Betulaceae (Birch Family) Pyrolaceae (Shinleaf Family) Betula papyrifera Paper Birch Chimaphila umbellata Pipsissewa Ranunculaceae (Buttercup Fagaceae (Beech Family) Family) Castanea dentate American Chestnut Coptis trifolia Goldthread Quercus alba White Oak Rhamnaceae (Buckthorn Family)

Quercus rubra Northern Red Oak Frangula alnus Glossy Buckthorn Quercus velutina Black Oak Rosaceae (Rose Family) Juglandaceae (Walnut Family) Photinia melanocarpa Black Chokeberry Carya glabra Pignut Hickory Prunus virginiana Choke Cherry Nyssaceae (Tupelo Family) Rubus hispidus Bristly Dewberry Nyssa sylvatica Black Gum Pinaceae (Pine Family) Forbs Pinus strobus White Pine Araceae (Arum Family) Tsuga canadensis Eastern Hemlock Symplocarpus foetidus Skunk-cabbage Rosaceae (Rose Family) Rubiaceae (Madder Family) Prunus serotina Black Cherry Mitchella repens Partridge-berry Ulmaceae (Elm Family) Sedges Ulmus americana American Elm Cyperaceae (Sedge Family) Shrubs and Woody Vines Carex pensylvanica Pennsylvania Sedge Aquifoliaceae (Holly Family) Ferns and Fern Allies Dennstaedtiaceae (Bracken Ilex verticillata Winterberry Family) Common Mountain- Nemopanthus mucronatus holly Pteridium aquilinum Bracken Fern Caprifoliaceae (Honeysuckle Dryopteridaceae (Wood-fern Family) Family) Viburnum acerifolium Maple -leaf Viburnum Dryopteris carthusiana Spinulose Wood-fern Viburnum nudum var. cassinoides Wild Raisin Onoclea sensibilis Sensitive Fern Lycopodiaceae (Clubmoss Cornaceae (Dogwood Family) Family) Alternate-leaved Cornus alternifolia Dogwood Dendrolycopodium obscurum Ground-pine Osmundaceae (Royal Fern Ericaceae (Heath Family) Family) Gaylussacia baccata Black Huckleberry Osmunda cinnamomea Cinnamon Fern Kalmia angustifolia Sheep Laurel Osmunda regalis Royal Fern Rhododendron viscosum Swamp Azalea Vaccinium corymbosum Highbush Blueberry Vaccinium pallidum Early Sweet Blueberry

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