Natural Communities of NH -- Photo Guide

Oak - mountain laurel forest  (S3)


(formerly Appalachian oak - mountain laurel forest)

Oak - mountain laurel forests consist of various mixtures of hardwood and coniferous trees, a sparse layer of dry to dry-mesic site herbs, and a shrub understory dominated by Kalmia latifolia (mountain laurel). The community is related to deciduous forests more prominent in the southern and central Appalachian Mountains dominated by understories of mountain laurel and giant rhododendron. In New Hampshire, it is restricted to south and southwest portions of the state and parts of the Lakes Region.
This natural community is characterized by a strikingly dense, sometimes impenetrable layer of mountain laurel. Broadleaf evergreen shrubs like mountain laurel and rhododendron are uncommon in upland forests of New Hampshire. Mountain laurel is found mostly on drier to somewhat moist upland sites and occasionally hummocks in swamps or along lake shores. The tree canopy of this community often consists of red and Appalachian oaks, but can be highly variable, and may sometimes even be composed of hemlocks or pines with no oak at all. Other than mountain laurel, shrubs and herbs are sparse or absent. Soils are acidic, nutrient-poor to weakly enriched, stony, medium to fine sandy loam soils (oligotrophic to submesotrophic).

While overstory composition may be similar to other mesic and dry Appalachian deciduous forests of the region, this community is considered distinct because of the significant effect mountain laurel has on other vegetation and its important role in ecosystem functions and processes (biomass, nutrient cycling, light). For example, the denseness of the laurel thickets often inhibits the growth of other vegetation, including tree regeneration. The broadleaf, evergreen character of mountain laurel (leaf longevity averages 2-3 years) and ability to root and butt-sprout contributes to its success at these fairly nutrient-poor sites. Taller laurel growth is common on moist sites whereas scrubbier forms occupy drier sites.

Characteristic Vegetation: The various tree species that may be present include red oak (Quercus rubra), white oak (Q. alba), chestnut oak (Q. prinus), black birch (Betula lenta), paper birch (B. papyrifera), hemlock (Tsuga canadensis), white pine (Pinus strobus), ironwood (Ostrya virginiana), beech (Fagus grandifolia), shagbark hickory (Carya ovata), red maple (Acer rubrum), sassafras (Sassafras albidum), and to a lesser extent sugar maple (Acer saccharum), American chestnut (Castanea dentata) sprouts, and white ash (Fraxinus americana). Some combination of oak(s), birches, and at least minor amounts of hemlock seem to be constant.

Mountain laurel (Kalmia latifolia) is abundant or dominant in the understory (generally 20-100%), often to the near exclusion of other understory vegetation. Other shrubs contribute a sparse to moderate cover and may include maple-leaved viburnum (Viburnum acerifolium), witch hazel (Hamamelis virginiana), flowering dogwood (Cornus florida), round-leaved dogwood (Cornus rugosa), striped maple (Acer pensylvanicum), beaked hazelnut (Corylus cornuta), and bush honeysuckle (Diervilla lonicera). Understory herbs are  typically sparse and include those found in other dry to dry-mesic transitional and Appalachian oak - hickory forests such as bracken (Pteridium aquilinum var. latiusculum), rough-leaved rice grass (Oryzopsis asperifolia), Indian cucumber root (Medeola virginiana), Pennsylvania sedge (Carex pensylvanica), starflower (Trientalis borealis), false Solomon's seal (Maianthemum racemosum), and New York fern (Thelypteris noveboracensis). Large whorled pogonia (Isotria verticillata) is a rare species known to occur in this forest type.



Good examples of this community can be seen at Mt. Wantastiquet (Hinsdale), Sheldrick Forest (Wilton), Beaver Brook Association land (Hollis), Chase Hill (Albany), and along the margins of Squam Lake (Holderness).

Oak - mountain laurel forests often occur as part of larger Appalachian oak - pine forest systems.


Oak - mountain laurel forest at Chase Hill (photo by Ben Kimball for the NH Natural Heritage Bureau)
Oak - mountain laurel forest at Chase Hill (photo by Ben Kimball)

Oak - mountain laurel forest in Albany, NH (photo by Ben Kimball for the NH Natural Heritage Bureau)
Oak - mountain laurel forest in Albany, NH (photo by Ben Kimball)

Oak - mountain laurel forest (a hemlock-dominated variant, with little oak) at Sheldrick Forest Preserve in Wilton (photo by Ben Kimball for the NH Natural Heritage Bureau)
Oak - mountain laurel forest (a hemlock-dominated variant, with little oak)
at Sheldrick Forest Preserve in Wilton (photo by Ben Kimball)

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