Fire Frequency Effects on Vegetation of an Upland Old Growth Forest in Eastern Oklahoma

Abstract

The purpose of this study was to determine the effects of prescribed fire frequency on the forest understory vegetation and forest composition in an old-growth forest of eastern Oklahoma. Prescribed fires over the past 20 years had a frequency of zero to five per decade. Tree density, basal area, overstory canopy, and understory plant cover was measured in each of eight treatment units. Sapling density and richness increase as fire frequency is reduced from five to zero fires per decade. Twenty years of low intensity fire at a frequency of five per decade is not sufficient for the reduction in tree density and canopy cover. While no herbaceous species were reduced in presence or cover by higher fire frequencies, many herbaceous species responded positively to increased fire frequencies. Frequent low-intensity fire maintains the dominance of fire tolerant oak species and the high biodiversity of herbaceous plants in the forest understory.