Initial Stand Conditions

Diameter distributions of the Good
Forty and the Poor Forty on the
Crossett Experimental Forest in the
first 35 years of the demonstration

Circumstantial evidence suggests that early 20^th century southern pine stands were largely even-aged before they were high-graded. Loblolly pine was known as old-field pine, and early photographs show that virgin upland pine-hardwood stands in the west gulf region had an open understory (Reynolds 1980). Similarly, virgin shortleaf pines in the Ouachita Mountains grew in open forest consisting of widely spaced overstory trees and little undergrowth (Smith 1986b).

Naturally occurring loblolly-shortleaf pine stands in the west gulf region originated after the first cutting of virgin forest in the early 1900s. In 1915, the Crossett Lumber Company, which owned the virgin forest land that would later become the CEF, harvested the area using a 38-cm (15-inch) stump limit cut, which was roughly equivalent to a 30-cm (12-inch) diameter limit cut. Between 1915 and 1934, no deliberate management was undertaken. The area supported occasional harvest of small hardwoods for chemical distillation and periodically was subject to arson fires. The company leased the 680-ha (1,680-acre) tract to the U.S. Department of Agriculture Forest Service (Forest Service) in 1934 for establishment of the CEF. While the company was interested in research information on management of second-growth forests, they also thought that Forest Service research staff could help prevent arson or control the resulting fires (Reynolds 1980).

Thus the use of uneven-aged silviculture in southern pines originated as a result of selective cutting. In 1937, the CEF Forties were stocked with scattered residual overstory trees that had survived the 30-cm (12-inch) diameter limit cutting in 1915, and the second-growth seedlings, saplings, and poles that seeded in after the cut and grew until 1937. On average, the stands were about 40 percent stocked by then (Reynolds 1969). The diameter distribution of the pine component in the CEF Good and Poor Forties in 1937 showed the reverse J-shaped curve typical of uneven-aged structure. This description of selective cutting and its effects on stand conditions at CEF was typical of that in the region; the stands in the Farm Forestry Forties and Hope Farm Woodland demonstrations had a similar history and initial condition. Because the stands in these demonstrations were relatively understocked when the selection method was initially applied to them, their rapid recovery to fully stocked conditions under the selection method shows that uneven-aged silviculture is a powerful tool for bringing understocked or cutover stands to full stocking within a short time (Baker and Bishop 1986; Farrar and others 1984, 1989).

Additional research illustrates not only the speed of the recovery, but also the degree of understocking from which recovery can occur. Baker and Shelton (1998a, 1998c) reported that stands with 20- to 30-percent stocking could develop acceptable stocking and basal area within 15 years, provided that competing vegetation is controlled with herbicide application. These threshold levels are lower than previously thought, and lower than threshold levels in the long-term demonstrations.

This suggests a strategy for implementing uneven-aged silviculture in southern pines across a forested ownership in the public or private sector. If the ownership supports both fully stocked even-aged stands and stands that for one reason or another are understocked, the best approach would be to convert the understocked stands rather than the fully stocked even-aged stands.