Plant competition, facilitation, and other overstory-understory interactions in longleaf pine ecosystems.

Abstract

Many of the stand structural characteristics of longleaf pine (Pinus palustris Mill.) forests that existed prior to European colonization have been altered or lost from past disturbance histories (Frost this volume). For example, often missing are the widely spaced, large-diameter trees, the all-aged stand structure that included a vigorous cohort of grass-stage longleaf pine seedlings, and the understory community composed of numerous woody and herbaceous species of short stature embedded within the flashy fuels of a wiregrass (Aristida beyrichiana Trin. & Rupr.) or bluestem (Andropogon spp.) matrix. Some of these structural features, such as the understory community, can be restored through modern silvicultural methods, vegetation management, prescribed fire, pine thinning, and artificial regeneration (i.e., planting or seeding) (Johnson and Gjerstad this volume; Walker and Silletti this volume). Other structural features, such as an all-aged distribution of longleaf pines, must be allowed to develop over time given appropriate disturbance regimes and the presence of keystone species (i.e., longleaf pine and wiregrass or bluestem) to "jump-start" the system. A mechanistic understanding of overstory and understory interactions will provide a sound basis for prescribing treatments designed to restore and maintain longleaf pine communities.

Citation

Harrington, Timothy B. 2006. Plant competition, facilitation, and other overstory-understory interactions in longleaf pine ecosystems. In: Jose, Shibu; Jokela, Eric J.; Miller, Deborah L., eds. The Longleaf Pine Ecosystem Ecology, Silviculture, and Restoration, Ch. 5: 135-156