Natural Communities of NH -- Photo Guide


Leatherleaf - black spruce bog  (S3)


Leatherleaf - black spruce bogs occur throughout the state and closely resemble leatherleaf - sheep laurel shrub bogs, but also have scattered and stunted black spruce and larch trees (generally 1-10% cover and less than 1-6 m in height). They are a type of oligotrophic dwarf heath bog (or very poor fen). There are essentially no tall shrubs below the stunted tree canopy, though there is a significant component of dwarf heath species such as leatherleaf, Labrador tea, sheep laurel, bog laurel, and small cranberry. Peat mats are grounded, and Sphagnum moss hummocks are usually very well developed. 

Shrub height averages ca. 0.48 m, pH averages 3.8, and peat is poorly decomposed in the upper 0.5 m. Hummocks are moderately to very well developed. Canopy trees (above the tall shrub layer) average ca. 6 m in height. This community is structurally similar to “muskeg” habitats of the boreal forest region in northern climates.

Characteristic vegetation: Black spruce (Picea mariana) and eastern larch (Larix laricina) dominate the canopy. Leatherleaf (Chamaedaphne calyculata), sheep laurel (Kalmia angustifolia), small cranberry (Vaccinium oxycoccos), and bog laurel (Kalmia polifolia) are characteristic of the dwarf heath layer. Hare's-tail (Eriophorum vaginatum), tawny cotton-grass (Eriophorum virginicum), three-leaved false Solomon's seal (Maianthemum trifolium), and Billing’s sedge (Carex trisperma var. billingsii) are frequent. Some combination of Sphagnum angustifolium, S. rubellum, and/or S. magellanicum dominates the moss layer. Sphagnum capillifolium is occasional but not as frequent as in leatherleaf - sheep laurel shrub bogs.

Variants: Two reasonably distinct variants are described.

1. Sphagnum rubellum - S. angustifolium variant: 
   This variant is most common in central and southern New Hampshire and is distinguished from the next variant by a generally stronger dominance of Sphagnum rubellum and S. angustifolium, the lack of Labrador tea (Ledum groenlandicum) and Sphagnum fuscum, a less developed hummock-hollow topography, and a lower abundance of trees. Average pH is 3.7, heath shrubs are less than 0.5 m in height, and peat is poorly decomposed in the upper 0.75 m. Hummocks average about 0.16 m, with a maximum height of less than 0.30 m.

2. Labrador tea - Sphagnum fuscum variant: 
   This variant is most common in northern New Hampshire and is distinguished by the presence of Labrador-tea (Ledum groenlandicum) and Sphagnum fuscum; a better developed hummock-hollow topography; and a higher abundance and structural complexity of the tree layer. Few-flowered sedge (Carex pauciflora) is occasional. Hummock height averages 0.25 m, with maximum heights averaging 0.4 m. The average pH is 3.95.


Good examples of this community occur near Umbagog Lake (Errol) and Duncan Lake (Ossipee), and at Whaleback Ponds (Errol), South Bay Bog (Clarksville), Trask Swamp (Alton), Hubbard Pond (Rindge), and Loverens Mill Preserve (Antrim).

Leatherleaf - black spruce bogs often occur as part of kettle hole bog systems and poor level fen/bog systems, and sometimes as part of patterned fen systems.

leatherleaf - black spruce bog in Canterbury (photo by Dan Sperduto for the NH Natural Heritage Bureau)
a leatherleaf - black spruce bog in Canterbury (photo by Dan Sperduto)

a leatherleaf - black spruce bog at Bradford Bog (photo by Ben Kimball for the NH Natural Heritage Bureau)
a leatherleaf - black spruce bog at Bradford Bog (photo by Ben Kimball)

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