Doctoral Dissertation Research: Range of Variability in Fire Regimes of Table Mountain Pine (Pinus pungens Lamb.) Stands, Jefferson National Forest, Virginia

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

An accurate determination of the historic and current fire regimes (including fire frequency, seasonality, and spatial scale) of yellow pine stands in the central Appalachian Mountains is crucial in efforts to restore diminishing pine populations in historically pine-dominated areas. Table Mountain pine (Pinus pungens Lamb.), the yellow pine of principle interest, has a distribution that extends from northern Georgia into central Pennsylvania and is a major component of the mixed oak-pine forest of central eastern U.S. highlands. After 60 years of fire suppression, however, fire-intolerant hardwoods and shrubs are achieving dominance in yellow pine stands and hindering the regeneration of Table Mountain pine. The goals of this Doctoral Dissertation Research Improvement project are (1) to determine the historic and current fire regimes of yellow pine stands in the central Appalachian Mountains, (2) to determine how cohort establishments are linked to past fires, (3) to determine the future stand composition by analyzing the changes in forest composition data, and (4) to use GIS to determine the relationships that exist among site-specific fire regimes (e.g., the movement of fire between individual pine stands). Collection of fire-scarred trees, stumps, logs, and snags has taken place on four mountains across the Jefferson National Forest of southwestern Virginia, and their scars have been dated through dendrochronological analyses. Information provided by these tree-ring analyses has shown a close association between fire occurrence and cohort establishment within a stand, with the establishment of many trees that coincide with a known fire year. Fire histories have provided information on the frequency and seasonality of fires, but not how fires affect vegetation. Age-structure analysis will be conducted to clarify the effects of fire on the species composition of an area. Fire history information, combined with age structure analysis, are expected to provide a detailed summary of the current composition of yellow pine populations, their relationships with past fire, and their prognosis for survival under the current fire regime. The importance of Table Mountain pine lies in its ecological value by increasing landscape diversity, by protecting areas prone to erosion, and by providing food and cover to a number of wildlife species. Table Mountain pine plays a major role in the regeneration of mountain forests after major fire occurrences. Fire ecologists and forest researchers predict that fire-intolerant species will eventually dominate traditional pine sites unless fire is restored to these ecosystems. In the absence of yellow pine, fire-intolerant hardwoods achieve dominance in central Appalachian forests. Such a change in species composition, particularly in the wildland-urban interface, would make accidental, large-scale, catastrophic fires more likely with little chance for healthy forest regeneration after the fire. This research will offer the data necessary for forest managers to reintroduce fire to yellow pine stands for the purpose of maintaining them in a healthy state. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.