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Hemlock Coves
Description
In north-facing ravines, the steep, rocky slopes are usually covered with hemlock and yellow birch. The ravines are cool and dark. The trees form a dense canopy and the scrub layer and understory are very sparse. Soils are rocky but high in organic matter and well drained. They remain moist and cool most of the year.
Selected Plants
Hemock cove along Canterbury Brook
Trees
- Tsuga canadensis (Eastern hemlock)
- Betula alleghaniensis (Yellow birch)
- Fagus grandifolia (Beech)
- Acer saccharum (Sugar maple)
Shrubs
- Acer pensylvanicum (Moosewood)
- Viburnum acerifolium (Maple-leaved viburnum)
Herbs
- Dryopteris intermedia (Common wood fern)
- Polystichum acrostichoides (Christmas fern)
- Mitchella repens (Partridge berry)
- Anemone quinquefolia (Wood anemone)
- Maianthemum canadense (Canada-mayflower)
- Huperzia lucidula (Shining clubmoss)
Occurrence
Hemock stand near the upper reservoir
Most of the hemlock coves are steep and intractable. The best examples occur along Black Rock Brook and Canterbury Brook. The cove along Black Rock Brook is best seen from the sharp turn on Mountain Road, where the dark green hemlocks stand out in all seasons.
Black Rock Brook cove is accessible from Aleck Meadow Reservoir, at the head of the cove, and from Brook Road, beyond the chlorinator. The cove along Mineral Spring Brook is accessible from Mineral Spring road by the Scenic Trail.
Ecology
Hemlock coves occur on cool, north-facing slopes and ravines along streams. They characteristically are densely shaded and have extremely sparse shrub and herb layers.
The hemlocks in the forest and through most of our area are dying due to predation from the hemlock wooly adelgid (Adelges tsugae). This small insect appears as white fluffy bumps on the twigs and undersides of leaves. It was accidentally introduced into North America from Japan about 40 years ago. The adults suck sap from the tree, killing leaves, twigs, and eventually, the entire tree.
History
The steep, rocky slopes of the hemlock coves made them unsuitable for farming and most logging operations. Hemlock trees were often cut for their tannin-rich bark which was used to tan leather.
Unless the adelgid infestations are controlled, the forest's hemlocks will probably be dead in four to five years.
Also Called
- Raup (1938): Hemlock hardwood association
- Eyre (1980): Hemlock-yellow birch
- Reschke (1990): Hemlock-northern hardwood forest
- Breden (1989): Mesic hemlock-hardwood forest
- Collins & Anderson (1994): Uplands, hemlock-mixed hardwoods
- NVCS: I.C.3.N.a.32 Tsuga canadensis—Betula alleghaniensis forest alliance
Selected References
For general references see the reference page.
- Brown, J.H. Jr., Casteneda, C., & Hindle, R. 1982. Floristic relationships and dynamics of hemlock (Tsuga canadensis) communities in Rhode Island. Bull. Torrey Bot. Club 109: 385-391.
- Hough, A.F. & Forbes, R.D. 1943. The ecology and silvics of forests in the High Plateaus of Pennsylvania. Ecol. Monogr. 13: 300-320.
- Orwig, D.A. and Foster, D.R. 1998. Forest response to the introduced hemlock woolly adelgid in southern New England, USA. J. Torrey Bot. Soc. 125:59-72.
Photos: Paul Harwood, Kerry Barringer