Fire Ecology and Management of Shortleaf Pine

Authored By: R. E. Masters

Shortleaf pine (Pinus echinata P. Mill.) occurs across a wider variety of climates, soils, topography, moisture regimes and fire regimes and thus community types, than any other pine species in North America with the possible exception of ponderosa pine (Pinus ponderosa Dougl. ex Laws.). Throughout the greater part of it range shortleaf occurs in mixtures with other pine and hardwood species. In spite of its adaptability and widespread distribution, it has declined in prevalence in the south primarily because of land use objectives that replace this species with pine species, particularly loblolly pine (Pinus taeda L.), that have faster growth characteristics in the short-term on industrial forest landholdings and on some non-industrial private lands. Also the history of selectively logging (high-grading) of this preferred pine species with negligence of proper site preparation and proper attention to capture of regeneration in mixed stands across its range has contributed to declines. Cutting in this manner shifts canopy dominance from shortleaf pine or mixed shortleaf pine-hardwood to dominance by hardwoods. Shortleaf is a shade intolerant species and will not naturally regenerate well in the presence of a low, dense midstory canopy or dense overstory canopy. Fire suppression has played a major role in declines of this species as fire intolerant and shade tolerant species have supplanted shortleaf as canopy dominants following natural mortality of shortleaf and canopy replacement by hardwoods through plant succession. To maintain canopy dominance shortleaf is dependent on frequent fire on better sites to give it a competitive advantage over hardwoods and other associated pines. On nutrient deficient shallow soils and exposed topographic sites, or following small to large scale natural disturbance, some element of shortleaf may be able to persist in the absence of fire. Typically in these settings shortleaf will occur in a mixture with other tree species in the absence of fire. Because of its adaptability and the various plant associations in which it occurs, shortleaf has been considered as either fire adapted, fire dependent, fire resistant, fire resilient and erroneously, fire intolerant (see Little and Mergen 1966, Givnish 1981, McCune 1988, Lawson 1990, Keeley and Zedler 1998).