An Appalachian original.
Known by many names--hickory pine, poverty pine, prickly pine-Table Mountain pine (Pinus pungens) is an Appalachian endemic. Found primarily on dry mountain slopes and exposed ridgetops from central Pennsylvania to northern Georgia, it often inhabits sites on which few other trees of this region will grow. On some sites, only the more rugged species that resist drought and exposure--like pitch pine, chestnut oak, and scarlet oak--are able to coexist with the hardy Table Mountain pine.
Despite its admirable tenacity, Table Mountain pine suffers from a severe PR problem. Few people other than botanists and ecologists really appreciate this tree. This lack of appreciation is based partly on economics: Unlike many of its important southern congeners, Table Mountain pine produces brittle and knotty lumber. Moreover, its sometimes stunted, heavy-limbed form does little to win new devotees.
Considering these undesirable factors, many authors have strived to find some redeeming feature in Table Mountain pine. Russell Peterson, in his Pine Tree Book, wrote that "Poverty pine
... is perhaps of some value in bringing completely wasted areas to at least a semblance of rejuvenation, preparing the land for the advent of more useful trees."
Even Andre Michaux, the botanist who named the tree after Table Mountain in North Carolina, where he first encountered it, found little to boast about in this species. He wrote, "The Table Mountain pine has no valuable properties to recommend it to notice in Europe; it will serve only to complete botanical collections and to diversify pleasure-grounds."
More maligned and misunderstood than worthless, Table Mountain pine was used locally for fuel and lumber throughout its range. Low-grade charcoal and rough lumber were the chief products made from its wood. Michaux noted that pioneers in the North Carolina mountains preferred turpentine collected from Table Mountain pine as a dressing for wounds. Today, the species is sometimes harvested for pulpwood, along with other pines and oaks of the region.
Although its economic offerings appear scant, the ecological value of Table Mountain pine is considerable. By quickly colonizing burned sites, the fire-dependent tree plays a major role in the recovery of mountain forests after fire. Contrary to some reports, forests of Table Mountain pine also provide habitat for many animals. During field studies in Table Mountain pine forests, I've either observed or found evidence of deer browsing on the understory, turkeys scratching for insects on the forest floor, scarlet tanagers nesting in the forest canopy, pileated woodpeckers pounding for insects on old pine snags, whippoorwills and ruffed grouse resting in the shrubs, and fence lizards scurrying up pine trunks. Even the cones of this pine support a unique creature, the mountain pine coneworm, a moth whose larvae feed only on cones of this species. I suspect that people who consider Table Mountain pine forests devoid of animals simply never spent enough time in them to see any!
The cones of Table Mountain pine, like those of many fire-dependent pines, are serotinous, meaning they remain closed for some time after maturity and open only after exposure to high temperatures, like those associated with forest fires. Cones of Table Mountain pine, however, may open on hot days during summer and autumn, so they may disperse seeds throughout the year. Release of seeds between fires may be a useful regeneration strategy on some sites, particularly where the seedbed is good, competing trees and shrubs are rare or absent, and fires are infrequent.
Partly opened serotinous cones of Table Mountain pine also provide food for nuthatches, chickadees, and woodpeckers, which extract seeds from gaps between the cone scales. At times, the red crossbill, a bird that feeds only on conifer seeds, may depend solely on Table Mountain pine seeds. Occasionally, the seed crops of conifers--like white, pitch, and Virginia pines--which share the mountain landscape with table mountain pine may all fail. Since serotinous cones of Table Mountain pine often accumulate on branches for 20 or more years and invariably a good number are open, there is usually more than enough seed to support hungry crossbills.
The cones are also the most striking feature of Table Mountain pine. Reminiscent of the closed-cone pines of the western U.S., cones of Table Mountain pine are large, heavy, and well armed with sharp, hooked spines. I once had the painful misfortune to slip and fall on one of these botanical caltrops. Impalement led me to quickly respect the ability of the spines to protect the cone and its contents!
Amazingly, the red squirrel appears to be undeterred by the cone's spiny armaments. The energetic critters often amputate whole cone-bearing branches from trees, dismember them by biting through the cones' scales, then feed on the exposed seeds. When the diner is done, all that remains of the stout cone is a pile of scales and a core that resembles a corn cob.
In the southern Appalachians, forests of Table Mountain pine usually appear as discrete patches in a hardwood forest matrix. The patchy nature of Table Mountain pine forests may be a result of topography, fire, or a combination of both. The forests frequently occur on exposed ridgetops and on dry, southerly mountain slopes.
Fire figures prominently in the origin and maintenance of most Table Mountain pine forests, particularly on sites favorable for the growth of hardwoods. Fire destroys the more competitive oaks, releasing large numbers of seed from serofinous cones and preparing seedbeds favorable for the establishment of Table Mountain pine seedlings. Fire thus resets the forest community to an earlier successional stage dominated by pines.
What happens to forests of this pine in the absence of fire? Depending on the site, the trees usually decline in importance, giving way to oaks. On dry, steep, exposed ridgetops and outcrops, Table Mountain pines may form self-maintaining, non-successional stands that persist in the absence of fire. On most other sites, however, their reproduction shuts down when oaks invade, primarily because of heavy oak-litter accumulations. My studies suggest that oak litter traps germinating pine seeds and, by preventing seeds or seedling roots from reaching moist soil, causes their death by desiccation. In mature pine-oak forests, Table Mountain pine seedlings occur almost exclusively in open microsites dominated by shallow pine litter. These microsites are quite rare, and in the absence of fire, it appears that a shortage of suitable seedling habitat strongly limits regeneration of Table Mountain pine.
Interestingly, Andre Michaux believed that fire was detrimental to the maintenance of Table Mountain pine. He wrote, "Of all the forest trees of America, this species alone is restricted to such narrow limits, and it will probably be among the first to become extinct, as the mountains which produce it are free of access, are favored with a salubrious air and a fertile soil, and are rapidly peopling; besides which, their forests are frequently ravaged by fire."
Time and increased knowledge of fire's role in Table Mountain pine forests have proven Michaux wrong. Other myths about this tree, particularly of its worthlessness, need also be laid to rest. Worth in the case of Table Mountain pine cannot be measured economically--it must be measured ecologically and aesthetically. Only when we recognize the diversity that Table Mountain pine forests impart to southern Appalachian landscapes, and their important role in forest recovery following fire, can we truly appreciate this unique and stalwart tree.
Charles Williams is an ecological consultant living in Blacksburg, Virginia.
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|Title Annotation:||Table Mountain pines|
|Author:||Williams, Charles E.|
|Date:||Jul 1, 1992|
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