Cape Town Lens: Pitch Pine Understory

A Cape Town University of the Western Cape tagged image from photographer – K.P. McFarland as published on Flickr.

Pitch Pine Understory

Image by K.P. McFarland

Black Mountain rises above the West River in Dummerston, Vermont to an elevation of 1,280 feet affording amazing views to the south and across to the Green Mountains to the west. The mountain originated as a mass of molten rock deep beneath the surface of the earth 345 to 395 million years ago. Magma rose from beneath the crust of the earth and intruded into the native rock to form a granite dome. Millions of years of erosion have exposed the durable granite that forms the core of the mountain.

The lower slopes of the mountain are dominated by hemlock and northern hardwood and white pine forests. A red pine forest dominates the lower western peak. While near the summit the forest becomes a pitch pine–oak-heath rocky woodland community. This forest community is relatively rare in Vermont. Pitch Pine and Scrub Oak are very rare and are at the northern portion of their range here. Mountain Laurel, rarely found in Vermont, produces incredible displays of showy pink flowers in June.

Amy Holt, a graduate student from Antioch New England University, conducted a study of the Pitch Pine population dynamics near the summit in 1996. I helped her get tiny cores from the trunks of the trees with a small auger that removes a pencil size rod of wood without hurting the tree. She used these cores to determine the ages of the trees. One of the trees began to grow in 1790 making it over 220 years old! Most of the trees were from the early 1990s.

Pitch Pine is a fire-adapted tree. It is usually found growing on sites with poor nutrients and a frequent fire history. Vast areas of Pitch Pine on the coastal sandplains of New Jersey, Cape Cod and Long Island are believed to have persisted with recurring fires for thousands of years. Rocky outcrops, like Black Mountain, that are dry, nutrient poor and subject to lots of lightening strikes that create fires are perfect for this pine. Pitch Pine fire adaptations include thick and corky bark that resists heat, ability to regenerate branches along the trunk, refoliation after scorching, and some cones that only open if subject to intensive heat (called serotinous cones).

Holt examined historic records to find out when Black Mountain underwent major disturbances such as fire or wind storms. The earliest record was a report of a major hurricane in 1778. Newspaper records recorded a major fire in 1911. Longtime residents remembered a fire in the 1940s. In 1963 the fire department began to keep complete fire records and there had been no fires.

The tree rings from her cores indicated that intensive regeneration of Pitch Pine occurred between 1790 and 1815 and again between 1910 and 1950, matching the periods when major disturbances were thought to have hit the mountain. Understanding the disturbance regime necessary to maintain this ecosystem is paramount for developing a management plan for the natural area.