The majority of upland hardwoods are second growth and are significantly influenced by soil type, physiology and past disturbance. Oak-hickory is the most widespread of the upland hardwood types and occurs on a range of well-drained sites, excluding rock, dry or shallow soil areas. Other upland cover types include the post oak-white oak communities, which occur on dry ridges and on shallow soils, and blackjack-post oak communities, which occurs occasionally on dry south-facing bluffs, thin-soil areas with impervious clay stratum. Lowland forest (or bottomland hardwood areas) occupy mainly mesic/hydric sites. Species composition in these areas are influenced by soil conditions and degrees of flooding. Typical communities include birch-sycamore (early successional floodplain types), yellow poplar-sweetgum-ash-red maple (occurring on poorly drained sites) and beech-maple-white oak- red oak (which occur on deep, rich, well drained soils).

The range of age classes is also diverse. Natural stands of pine over 110 years old and hardwood stands over 200 years old are among the oldest age classes of timber, while new stands are being planted yearly. Many plantations have been established since 1931. The oldest and most common are loblolly pine. Other old plantations include white pine (1931), longleaf pine (1935), yellow poplar, and bald cypress (1937).

Over the past 60 years silvicultural techniques -- including prescribed burning, thinning, harvesting, planting and natural regeneration -- have been used to develop timber stands representing a wide age class distribution and a diverse set of cover types. Actively managed pine and hardwood stands are interspersed with areas reserved for study in their natural state.