Disturbance and scale effects on southern old-growth forests (USA): The sand pine example

Sand pine (Pinus clausa [Chapm. ex Engelm.] Vasey ex Sarg.), often a monotypic dominant of the Florida (USA) scrub assemblage, is an early successional tree species that is small in size, short-lived, and disturbance dependent. It does not conform to traditional images of old-growth forest. Nevertheless, to implement old-growth policy, the U.S. Forest Service has published stand-scale quantitative guidelines for recognizing old-growth sand pine (Outcalt 1997). Although the policy is well intentioned, we question the conceptual basis and management perspective implicit in developing a stand-scale definition of old-growth sand pine. Our principal concerns involve matters of scale and disturbance suppression. A stand-scale perspective on management of old-growth sand pine is doomed to failure: if fires are allowed to burn, older forests will be consumed; if fires are suppressed, sand pine will likely be replaced by shade-tolerant associates. A landscape-level management framework is essential to allow for a spatiotemporally shifting pattern of mature sand pine patches embedded within a matrix of younger scrub. Moreover, we caution that modern scrub vegetation in wilderness areas occurs on a small scale and is dramatically altered by fire suppression; therefore, it is imprudent to use wilderness areas as a standard for judging the character of a sand pine scrub landscape in pre-European-contact conditions.