Mesic Pine-Oak Sandplain Forest

Ecology and Physical Setting

Southern New England is the real home of this community. Oaks and pines are the dominant vegetation in much of eastern Massachusetts and southern New Hampshire, where glacial outwash prevails, and where historical land use has had a significant impact on forests. 

In Vermont, we find similar conditions in the Champlain Valley, the Southern Vermont Piedmont (especially the Connecticut River Valley), and portions of the Taconic Mountains and Vermont Valley. Coarse glacial and post-glacial surficial deposits are common in these regions. While these deposits can be of various origins (including deltas, valley-side terraces, and eskers), they all create a similar setting: a flat or nearly flat terrace, often incised by streams creating steep slopes, with coarse, well-drained soils. Red oak, black oak, and white pine can compete well on these sandy terraces and slopes.

Mesic Pine-Oak Sandplain Forest is closely related to Dry Pine-Oak-Heath Sandplain Forest. They occur on similar soils and landscape settings, but the primary distinctions are the frequency of fire and the difference in soil moisture. Mesic Pine-Oak Sandplain Forests occur in settings that historically may have been less prone to lightning-caused fires than Dry Pine-Oak-Heath Sandplain Forests. These settings include small, sheltered terraces and the incised slopes of larger deltaic flats. In addition, at some sites, the soils likely hold enough moisture to limit the spread of any fires that do start. When present, these relatively moist soils support more mesic-site species. 

Vegetation

We have no known undisturbed examples of this forest type, so it is difficult to fully understand its natural vegetation. Historical information, together with our studies of some of the younger examples, suggests that mature Mesic Pine-Oak Sandplain Forests will have white pine, red oak, and black oak as canopy dominants. Black oak is absent in many of the younger examples. Pitch pine is usually not found in these forests. Red maple, beech, and hemlock are abundant in some examples, and the latter two species may eventually become dominant on these sites in the absence of disturbance. The shrub layer is a mixture of tall shrubs like witch hazel and smooth shadbush, and low shrubs including blueberries and maple-leaved viburnum. Herbs are generally sparse; they include wintergreen, pipsissewa, and bracken fern.

Occasional wet sites occur within this community when thin clay layers are found in the otherwise well-drained coarse soils. These clay layers impede water and transport it laterally. Where this water emerges as seepage on slopes at the edge of a terrace, the growing conditions can be enriched. These places can support species like sensitive fern, scouring rush, white ash, and basswood.

Wildlife Habitat

Mesic Pine-Oak-Heath Sandplain Forests provide an unusual and important combination of wildlife habitats. They are sandy and dominated by oaks, but often occur near large rivers. Acorns are a primary food for wood ducks, which may both feed in these forests and nest in mature tree cavities that are near water. Fowler’s toad is a very rare species in Vermont, known only from near the Connecticut River and its tributaries. It requires deep sandy soils for burrowing and, to our south, is frequently found in oak-pine forests near ponds or permanent water. Mesic Pine-Oak-Heath Sandplain Forest provides these habitat conditions and at least one of Vermont’s historic populations occurred in this community type. 

Red oak and black oak also provide an important source of acorns used by a wide variety of birds, mammals, and insects, including grey squirrel, eastern chipmunk, white-tailed deer, and black bear. Pine warblers, eastern wood pewees, and scarlet tanagers all nest in this community. Acorn weevil is a native beetle that relies on acorns for food and reproduction. 

Successional Trends

Most Mesic Pine-Oak Sandplain Forests have been cleared in the past. White pine is usually the first tree species to recolonize these sites, followed later by red oak. At sites with black oak, it seems to be slowest to establish in the canopy. All three of these species can tolerate summer droughts and occasional fires.

In Mesic Pine-Oak Sandplain Forests, natural disturbances such as fire and windstorms can change the species composition temporarily. In addition to white pine, other early-successional species include black birch, black cherry, and bigtooth aspen. Fires that remove the duff layer and create canopy openings can result in a transition to a Dry Pine-Oak-Heath Sandplain Forest characterized by pitch pine and heath shrubs.

Related Communities

• Dry Pine-Oak-Heath Sandplain Forest is very closely related to Mesic Pine-Oak Sandplain Forest. Both occur on coarse, well-drained soils. In the Champlain Valley, the two communities are often juxtaposed and interfingered. The main differences are soil moisture and fire regime. Dry Pine-Oak Heath Sandplain Forests have drier soils and are more prone to frequent fires.
  
   
• Dry Red Oak-White Pine Forest can have similar canopy species but is found on till or shallow-to-bedrock soils as opposed to coarse, well-drained soils. Black oak is absent.

Conservation Status and Management Considerations

This is a rare community in Vermont, and we know of no mature examples. Several of the known examples are on conserved lands. Additional examples should be sought out for conservation. At several sites the persistence of this community is threatened by non-native, invasive species. Deer browse is a threat to oak regeneration. Any timber management should consider natural ecological processes and should encourage regeneration of the species that would naturally grow on these sites.

Distribution/Abundance

Mesic Pine-Oak Sandplain Forest is a rare community in Vermont, found only in the warmest climate areas on coarse, well-drained soils. Similar communities are common in southern New England.

Characteristic Plants

Trees

Abundant Species 

White pine – Pinus strobus

Red oak – Quercus rubra

Occasional to Locally Abundant Species 

Black oak – Quercus velutina

Eastern hemlock – Tsuga canadensis

American beech – Fagus grandifolia

Red maple – Acer rubrum

Black birch – Betula lenta

Shrubs

Abundant Species 

Witch hazel – Hamamelis virginiana

Maple-leaved viburnum – Viburnum acerifolium

Occasional to Locally Abundant Species

Beaked hazelnut – Corylus cornuta

Smooth shadbush – Amelanchier laevis

Sweet fern – Comptonia peregrina 

Striped maple – Acer pensylvanicum

Black huckleberry – Gaylussacia baccata

Herbs

Abundant Species

Bracken fern – Pteridium aquilinum

Wintergreen – Gaultheria procumbens

Pipsissewa – Chimaphila umbellata

Occasional to Locally Abundant Species

Starflower – Lysimachia borealis

Sarsaparilla – Aralia nudicaulis

Poverty grass – Danthonia spicata

Intermediate wood fern – Dryopteris intermedia

Invasive Non-native Plants

Norway maple – Acer platanoides

Morrow’s honeysuckle – Lonicera morrowii

Glossy buckthorn – Frangula alnus

Common buckthorn – Rhamnus cathartica

Rare and Uncommon Plants

Scarlet oak – Quercus coccinea

Smooth false-foxglove – Aureolaria flava

Spotted wintergreen – Chimaphila maculata 

Hay sedge – Carex siccata

Blunt-lobed grapefern – Botrychium oneidense

Associated Animals

Eastern gray squirrel – Sciurus carolinensis 

Southern flying squirrel – Glaucomys volans

Eastern wood pewee – Contopus virens

Scarlet tanager – Piranga olivacea 

Pine warbler – Dendroica pinus 

Wood duck – Aix sponsa 

Rare and Uncommon Animals

Fowler’s toad – Anaxyrus fowleri 

Places to Visit

Sunny Hollow Natural Area, Colchester, Town of Colchester



Wilgus State Park, Weathersfield, Vermont Department of Forests, Parks, and Recreation



Bellows Falls Union High School Forest, Westminster



Black Mountain Preserve, Dummerston, The Nature Conservancy