Monday, January 14, 2013
There are places here in the Southeast that naturalists call “pocosins.” These are generally thought of as wetland habitats of the coastal plain, dominated by a fairly large list of plants, most of which are adapted to fires. That is, they respond “positively” to occasional burning. Pocosins are often characterized by peaty soils derived from sphagnum moss deposits. The natural vegetation of these fascinating ecosystems includes many species of shrubs and trees which bear leathery, waxy, aromatic foliage, especially magnolias, several different hollies, and an assortment of species in the “heath” family, such as fetter-bush, dog-hobble, huckleberry, wild azaleas, and blueberries, these plants commonly forming extremely dense shrub layers. Such foliage, and in such crowded conditions actually supports fire, and a burning pocosin can be a dramatic situation: hot fires supported by blazing plant tissue, popping and crackling, racing through the undergrowth and reaching into the crowns of the trees. Such a relationship that plants have with fire would seem to be odd, in that we think of fire, most of the time, as destroying things in nature. But of course, naturally-occurring fires have had an extremely beneficial effect on many of the species that we now refer to as “fire-adapted.” This is one of those plants.
It’s a pine, of course, one of the dozen or so southeastern species in the genus Pinus. This particular one, though, is perhaps a bit more obscure than the others. For one thing, the pocosin habitats that it prefers are not normally the best places for picnics or flying kites. It is a relatively small pine, usually not any taller than 70 feet or so, often with gnarly branches, and not particularly valuable as a timber source. The trees are unusual in being able to survive having all their foliage burned away…as they readily resprout, following a fire, the trunk sometimes taking on a furry or bristly look with its newly appointed needles. The needles are held in clusters of 3’s, each bundle wrapped at the base, as in other pine species, by a papery little sheath. Male cones and female cones develop on the same individual; this is an additional shared feature of all pines. The male cones, or “pollen” cones, are about an inch long, dropping their pollen in the spring. The female cones, of course, are the ones that produce the seeds.
These “seed” cones are distinctive among the pines, having a squatty, rounded shape, and they are often just as wide as they are long. Each scale of the cone is only weakly prickled at its tip, so the cone can be squeezed in your hand without hurting. (Not so with most other pine cones!) The stalkless cones start out green, then maturing to a sort of reddish-brown, and they remain on the branch for years, commonly becoming gray. The seeds within the cones are released rather slowly, and often only after a fire has gone through the area. The seeds don’t germinate well unless they are on a bare layer of sand or peat, and of course the fire helps with this.
[Answer: "Pond pine," Pinus serotina]
John Nelson is the curator of the Herbarium at the University of South Carolina, in the
Department of Biological Sciences, Columbia SC 29208. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or call 803-777-8196.