Midstory Hardwoods Inhibit Deer Forage in Loblolly Pine Plantations

Abstract

The basal area of a hardwood midstory developed inversely to the basal area of pine. Within 2 years after hardwood midstory elimination at pine age 42, herbage dry matter increased from 303.3 to 866.3 kg/ha and browse increased from 424.4 to 1,050.8 kg/ha. During the next 3 years, herbage yields increased further to 957.2 kg/ha and browse to 1,363.6 kg. The increases were directly related to hard- wood basal area before midstory elimination. After the midstory was removed herbage yields varied in- versely with pine basal area, but browse yields were not significantly influenced by pine basal area. J. WILDL. MANAGE. 41(4):677-684 The invasion and uncontrolled growth of hardwoods in loblolly pine (Pinus taeda) plantations can substantially limit the carrying capacity of millions of acres of habitat for white-tailed deer (Odocoi- leus virginianus) in the South. Without pre- scribed burning or other control measures in plantations on a sawtimber rotation, in- vading hardwoods develop a midstory of low shade that impedes the growth of herbaceous and woody forage for deer (Blair and Enghardt 1976). The density and development of a hardwood midstory is largely governed by both intensity of site preparation and thinning practices. In- tensive methods of site preparation such as discing appreciably deter hardwood inva- sion by destroying rootstocks, but such methods eliminate palatable species of woody deer forage. Periodic thinning of pine plantations enhances the midstory de- velopment by reducing competition from the dominant pine overstory. This paper de- scribes the ecological association between the pine overstory, the hardwood midstory, and understory vegetation in planted lob- lolly pine stands managed at different levels of pine basal area.