Effects of long-term annual and periodic burning on tree survival and growth in a Missouri Ozark oak-hickory forest

In a Missouri Ozark Mountains oak-hickory forest, long-term annual and periodic burning regimes decreased survival of Carya and Erythrobalanus oak species, but had little impact on survival of Quercus stellata. Reductions in survival of Carya and Erythrobalanus species were greater in periodically- than in annually burned plots. Compared with e. stellata mortality, Carya mortality was less closely related to preatreatment diameter, possibly because of drought-related mortality between 1972 and 1984. Erythrobalanus mortality was likely related to drought both during the first measurement interval, between 1949/1951 and 1964, and during the last period, between 1972 and 1984. Survival increased with pretreatment diameter for e. stellata and peaked at an intermediate diameter for the Erythrobalanus species. The relationship between diameter and survival was likely associated with self-thinning and natural life-span limits of trees and was modified by fire regimes. Fire accelerated the loss of small-diameter trees in all species. The results suggest that use of fire as a tool to influence species composition oak-hickory forests must include considerations of stand age, species life-span, stages of stand development and environmental stresses.