Stump sprouting dynamics during stand initiation under alternative silvicultural treatments in a Midwestern bottomland, mixed-species hardwood forest

by

Matthew G. Olson and Benjamin O. Knapp

(MGO) Missouri department of Conservation, Regional Science Research Center, 551 Joe Jones Blvd., West Plains, MO, 65775, (BOK) Department of Forestry, University of Missouri-Columbia, 203-S ABNR Building, Columbia, Missouri 65211

Abstract – Midwestern bottomland hardwood forests are often composed of species that are capable of sprouting vigorously, yet little is known about sprout develop within these mixed-species systems. Information on sprouting of Midwestern bottomland forests can assist managers in developing silvicultural prescriptions that consider sprouting as a regeneration source. This study describes stump sprouting dynamics of 11 species or species groups in Midwestern bottomland hardwood forests following two levels of overstory removal, clearcutting with reserves (CCR; ~2.0 m2/ha residual basal area) and basal area retention (BAR; ~7.8 m2/ha residual basal area), in the first three growing seasons after harvesting. We hypothesized that sprouting probability would be significantly affected by species and size of parent trees and that growth rates of sprouts would be greater in CCR than BAR plots. We observed significant, negative relationships between stump sprouting probability and the size of parent trees for most species in this study. The height of dominant sprouts was greater in the CCR than the BAR plots after the second growing season, indicating that relatively low levels of canopy retention (30% of pre-treatment basal area in BAR) reduced height growth within the first few years after cutting. Stump survival varied among species over the three year study period. Stump sprouts of American sycamore and green ash maintained over 80% survival, while the survival of several other species, including bottomland oaks, was around 50%. Our results suggest that sprout-origin regeneration can be a major contributor to the development of Midwestern bottomland hardwood forests, with the potential to affect the composition of the regenerating cohort.