Effects of fire exclusion on the longleaf pine ecosystem of Upland Island Wilderness

Vegetation and fuel conditions of longleaf pine ( Pinus palustris) communities in Upland Island Wilderness and Boykin Spring Longleaf, a Texas Natural Heritage Site, in the Angelina National Forest were evaluated in order to understand the effects of fire suppression and exclusion in the wilderness. Statistical analysis and multivariate ordination techniques were used to compare areas of reduced fire frequency in the wilderness with areas in the adjacent, frequently burned Texas Natural Heritage Site and to relate differences within and among the areas to important environmental and site variables.; The major environmental and site variables identified in the study were percent canopy, management intensity, and soil moisture availability as related to topographic position and soil conditions. Percent canopy was highly correlated with management history and fire frequency and appeared to have a substantial influence on herbaceous and woody vegetation. Midstory encroachment was highly correlated with percent canopy and soil moisture conditions influenced by topographic position, soil texture, depth to subsoil, and aspect. It was inferred from the results that fire frequency and management history were important underlying factors that interacted with environmental variables to influence vegetation distribution.; The results of the study suggest that vegetation and fuels in Upland Island Wilderness have been substantially affected by reduced fire frequency and that a comprehensive program of prescribed burning will be needed to restore historical ecosystem conditions and reduce hazardous fuels.