Characteristics and dynamics of an upland Missouri old-growth forest

We describe the structure, composition, and dynamics of Schnabel Woods, an 80-acre mixed mesophytic old-growth stand located in the loess-covered River Hills adjoining the Missouri River floodplain in central Missouri. In 1982 all trees on a 1.5-ac northwest-facing plot and a 1.5-ac southeast-facing plot were mapped and measured. In 1992 we remeasured those plots to observe current conditions and changes in species composition and stand structure over time. In 1992 density was 381 trees/acre, basal area was 124 ft²/ac, and the mean dbh was 5.2 in (for trees = 0.8 in dbh). The stand was fully stocked at 101%. Between 1982 and 1992 tree density decreased by 11% while total basal area remained constant. However, basal area did shift among species groups; basal area for northern red oak and white oak increased by 10% while basal area for other species groups remained the same or decreased. The volume of down wood with a minimum diameter = 4 in averaged 338 ft²/ac over both plots. Litter dry weight averaged 4.9 tons/ac and was significantly greater on the southeast than on the northwest aspect. Northern red oak dominated the overstory, but maple dominated the understory and comprised 67% of the ingrowth. Current dynamics are driven by fine-scale treefall gaps, where maples are replacing oaks.