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Cliffs and Rock Outcrops

Description

Cliff associations grow on steep slopes with exposed gneiss or granite bedrock. These are usually made up of a series of ledges with piles of talus at their base. Most cliffs in the Black Rock Forest face south and are exposed to full sun because of the tilt of the underlying bedrock layers. A thin layer of soil is found on ledges and in cracks of the rock, and plant cover is usually sparse.

Mount Rascal

Mount Rascal

Stunted trees grow on ledges and in cracks. The shrub layer is also very sparse or absent. Rock surfaces are usually covered only with lichens, but a few mosses and liverworts grow where the rock is damp. Cracks and ledges support a community very similar to other exposed rock outcrops.

Selected Plants

Trees

Shrubs

Herbs

In cracks and on ledges

Lichens

On rocks

Occurrence

Outcrop near Aleck Meadow

Outcrop near Aleck Meadow

Eagle's Cliff and Split Rock are both tall cliff faces with good views from their summits. Eagle's Cliff can be reached along the Scenic Trail, beyond Jim's Pond. Split Rock overlooks Sutherland Pond and can be reached on the Split Rock Trail.

Generally, cliff associations are widespread in the Forest, but they tend to be small. Many occur along the southwest face of Rattlesnake Hill and in the area southwest of Sutherland Pond.

Ecology

The bedrock of the cliffs is usually gneiss, but outcrops of granite are also found. Soils are absent or very thin and are usually found only in cracks or on ledges. Water-holding capacity is extremely low. Plants can only root deeply in crevices.

Cliffs and rock outcrops are very susceptible to fires due to their dryness. After fires, fire cherry and fireweed quickly appear, but are soon eliminated by the appearance of huckleberry and sprouting trees.

Also Called

References

Photos: Kerry Barringer