Regenerating mixed bottomland hardwood forests in north Missouri: Effects of harvest treatment on structure, composition, and growth through 15 years

Abstract

Bottomland forest ecosystems provide important economic and ecological benefits within the midwestern and southern United States, yet silvicultural guidelines for reaching management objectives have been poorly developed outside the southeastern region. Bottomland hardwood forests are highly productive and dynamic ecosystems that contain a multitude of herbaceous and woody plant species and can support an abundance of wildlife throughout stand development. In particular, oak species are often favored for timber and wildlife values but may occur in low abundance due, in part, to challenges with regeneration. This study was designed to examine the structure and composition of a mixed bottomland hardwood forest (elm/ash/cottonwood) in northeast Missouri in response to two regeneration harvest treatments (i.e., clearcut with reserves and basal area retention) and one unharvested control through 15 years after harvest. Results indicate that clearcutting had a greater effect on subsequent forest composition and stand development than partial harvesting. In particular, the clearcutting treatment increased the relative basal area of American elm and relative abundance (trees per hectare) of green ash. Results suggest that the regeneration harvests did not increase the abundance of oak regeneration. However, the growth rates and the size of oak stems within the regeneration cohort were comparable to competing species, suggesting the oaks within the regeneration cohort presumably originated from advance reproduction. Thus, these results support the importance for establishing oak advance reproduction prior to regeneration harvest within bottomland forests.