A swamp on mineral soils overlain with peat that occurs in depressions which may receive ground water discharge. The swamp may be flooded in spring and dry by late summer. The forest commonly occurs on very acid (pH<4.5) woody peat at margins of small rain fed basins. The canopy is usually fairly closed and there is a sparse shrub and ground layer. Characteristic trees are hemlock, yellow birch, and red maple, black ash, and, formerly, American elm. Locally, white pine may be one of the dominant trees. Tall shrubs of acid wetlands such as highbush blueberry, black chokeberry and Viburnum cassinoides are present. The herb layer may be sparse and species-poor. Characteristic herbs are Canada mayflower, cinnamon fern, and goldthread.
Hemlock-northern hardwood forest
A forest that typically occurs on lower slopes of ravines, on cool, mid-elevation slopes, and at the edges of drainage divide swamps. Hemlock is a co-dominant species with one to three others: beech, sugar maple, red maple, black cherry, white pine, yellow birch, black birch, red oak, and basswood. Shrubs have low abundance, but striped maple may be present. Herbs characteristic of northern and montane areas are common.
Successional northern hardwoods
A forest with more than 60% canopy cover of trees that occurs on sites that have been cleared or otherwise disturbed. Dominant trees are usually two or more of the following: red maple, white pine, white ash, gray birch, quaking aspen, big-tooth aspen, and, less frequently, sugar maple and white ash. Tree seedlings and saplings may be of more shade tolerant species. Shrubs and ground cover species may be those of old-fields. In abandoned pasturelands apples and hawthorns may be present in the understory.