Natural Communities of NH -- Photo Guide

Hemlock - oak - northern hardwood forest  (S4)


(formerly hemlock - beech - northern hardwood forest)

Hemlock - oak - northern hardwood forest is a common mixed coniferous - deciduous forest of middle elevations (800 - 1,500 ft. elevation) in central New Hampshire. It also occurs as more isolated patches on mesic sites in southern parts of the state, and in valley-bottom settings in the mountains (locally to 2,000 ft. elevation). The canopy is characterized by a mix of classic northern hardwood species such sugar maple, yellow birch, and beech, along with hemlock. Red oak and white pine are also typically present, but diminish in abundance in examples in the mountains or at higher elevations. This community is fairly distinct but transitions to hemlock - beech - oak - pine forest at lower elevations and south of the mountains, where sugar maple and yellow birch are infrequent or absent.

This community is found primarily on moderately well to well drained soils (occasionally somewhat poorly drained) of coarser parent materials, particularly compact till and firm ablation tills and sometimes on outwash, kame-terraces, and shallow-to-bedrock soils. Soils are also generally acidic and moderately nutrient-poor.

Characteristic Vegetation: Hemlock (Tsuga canadensis) and beech (Fagus grandifolia) are the primary late-successional species in the tree canopy. Red oak (Quercus rubra) and yellow birch (Betula alleghaniensis) are often present as associates. Hemlock and/or beech may only be present in the understory in successional examples. Other trees are less constant and more variable in prominence including sugar maple (Acer saccharum) (although it tends not to dominate in New Hampshire examples), white pine (Pinus strobus), white ash (Fraxinus americana), red maple (Acer rubrum), red spruce (Picea rubens), and balsam fir (Abies balsamea).

The most consistent plants in the shrub layer are striped maple (Acer pensylvanicum) and hobblebush (Viburnum lantanoides) but they are typically somewhat sparse. Herbs that are more abundant or frequent than in typical northern hardwoods include Indian cucumber root (Medeola virginiana), partridgeberry (Mitchella repens), and goldthread (Coptis trifolia). Herbs that are more abundant than in most hemlock - beech - oak - pine forests include intermediate wood fern (Dryopteris intermedia), northern wood sorrel (Oxalis montana), and shining clubmoss (Huperzia lucidula).


Good examples
of this community occur at the Bartlett Experimental Forest (Bartlett) and Pisgah State Park (Winchester).

Hemlock - oak - northern hardwood forest often occurs as part of a larger northern hardwood - conifer forest system, and sometimes as part of a hemlock - hardwood - pine forest system.


 Hemlock - oak - northern hardwood forest in central New Hampshire (photo by Dan Sperduto for the NH Natural Heritage Bureau)
Hemlock - oak - northern hardwood forest in central New Hampshire (photo by Dan Sperduto)

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