Marine Terrace Depression

Description

The forested plant community phase (1.1) has a medium to dense canopy cover, averaging 85 percent and ranges from 75 to 95 percent. It consists of a stratified mixture of conifer and northern hardwood tree species. Northern white cedar (Thuja occidentalis) forms a canopy over other codominant or intermediate species such as red spruce (Picea rubens), except along the coast, red maple (Acer rubrum), gray birch (Betula populifolia), black ash (Fraxinus nigra), balsam fir (Abies balsamea), black spruce (Picea mariana), and tamarack (Larix laricina). Some sites have more red spruce or red maple depending on their previous forest management or location.

The understory may be sparse due to a dense conifer overstory cover except for small open areas, less than a 0.1 of an acre, where a wide variety of forbs, ferns, and shrubs grow. Under the dense conifer overstory, only small scattered shade-tolerant and moisture-loving plants grow. Plants include balsam fir regeneration, a few sedges, and many species of feather-mosses and leafy liverworts. The moss grows over the mounds, on downed dead wood, and the bottoms of trees throughout this site. Due to the dense, shady, understory tall shrubs are almost non-existent. In the small open areas, taller shrubs, such as speckled alder (Alnus incana), are present along with wild sarsaparilla (Aralia nudicaulis) and dwarf red raspberry (Rubus pubescens). Clumps of cinnamon fern (Osmunda cinnamomea) and small patches of sensitive fern (Onoclea sensibilis) are also common on the mounds. Small forbs usually found on hummocks include maystar (Trientalis borealis), blue-bead lily (Clintonia borealis), and bunchberry (Cornus canadensis). Eastern poison-ivy may also be present on some sites and should be avoided because it can cause severe dermatitis. On one sample site, skunk cabbage (Symplocarpus foetidus) was abundant in the pools of water. Very few grass or grass-like plant species were found on this site. There were more sedges than grasses and both appeared in small clumps on mounds scattered throughout. Typical sedges include three-seeded sedge (Carex trisperma).

Submodel

Description

The ponded state is a result of beaver activity. This state is frequently ponded for long durations. The description is based on historical descriptions, site index data, professional consensus of experienced ecologists, and analysis of field work. This state is perceived to be a mixture of shrubs, typically speckled alder (Alnus incana) and graminoids, such as tussock (upright) sedge (Carex stricta) with few if any mature trees because they have been drowned out or eaten by the beavers.

Submodel

Description

The harvested state is quite common in Maine. Most harvesting is by an individual tree or group selection method in this MLRA and on this site. The reference forest has been harvested for the most desirable species, northern red cedar and spruce. The remaining forest stand consists of young red maple and gray birch with a few balsam fir, tamarack, and black ash. This state is most like the reference state in plant composition particularly in the understory if only small openings are created like for an individual tree selection harvest. Group selection harvests may make larger openings temporarily that will allow other species to grow for very short periods of time. If northern red cedar and red spruce are harvested in large quantities, the harvested state will become dominated by red maple and other faster growing species.

Submodel