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Grassy Balds

Grassy Bald with Andropogon and Danthonia

Grassy Bald with Andropogon and Danthonia

Description

On the tops of hills and along ridges, grasses dominate where the bedrock is exposed. These sites are very dry and very exposed to sunlight and weather. There is no tree layer, but occasional trees may grow in favorable spots. Widely scattered shrubs may occur along crevices or in hollows where organic matter accumulates. On exposed rock the lichen cover is similar to that on cliffs. Soil occurs in shallow layers over the bedrock and in cracks in the exposed rock.

Selected Plants

Trees

Shrubs

Herbs

Lichens on rocks

On shallow soil in hollows and crevices

In slightly enriched sites

Occurrence

Good examples of balds can be found at the top of Rattlesnake Hill, and along Sackett Ridge. Small pockets can be found on Mount Misery, Pine Tree Hill, and Frog Hill. This habitat is very sensitive to trampling. A good example of a disturbed bald is the summit of Black Rock. The ridge of Mount Rascal shows what the community looks like a few years after a fire.

Please be very careful when visiting these sites. They are very fragile.

Ecology

The shallow soils limit the growth of trees and shrubs, which can neither root deeply nor draw much water. Soils are made up of broken or eroded rock and whatever organic matter accumulates from plants and windblown leaves. They are acidic and nutrient-poor.

These sites become very dry in the summer and are very susceptible to fire. In the winter, much of the snow cover is blown off the outcrops, and plants are exposed to the drying winds. Plants that can survive under these conditions are either annuals (which overwinter as seed) or perennials whose winter buds are close to or under the ground.

This habitat intergrades with, and is often mixed with, hilltop scrub and hilltop woods. Niering (1953) interpreted the sequence of associations from rock outcrop to bald, then hilltop scrub, and hilltop woods as a successional change in which, over time, an exposed hilltop would be gradually transformed into a woodland as soils were built up. In the forest, these associations do change, but the change is not in a single direction toward a stable climax. It is continuous and multidirectional. Erosion, shedding of rock layers due to winter ice, fire, disease, and infestation as well as disturbances like trampling and tree cutting all have the effect of changing the vegetation from woods to scrub, scrub to meadow, meadow to rock and back.

Also Called

Selected References

For general references see the reference page.

Photo: Kerry Barringer