Rehabilitation of Understocked Loblolly-Shortleaf Pine Stands - III. Natural Stands Cutover 15 Years Previously but Unmanaged

Plots in an unmanaged loblolly-shortleaf pine (Pinus taeda L.-P. echinata Mill.) stand that had been cutover I5 yrpreviously were established to representfive stocking levels: 10, 20, 30, 40, and 50%. The stand was on a good site (site indexLob = 90 ft at 50 yr) and had uneven-aged character. Two competition control treatments (none and individual tree release using herbicide) were also assigned. Three, five, and nine years later, the plots were reinventoried to determine: (1) the rate at which the understocked stands recovered, (2) the minimum stocking level requiredfor successful rehabilitation, and (3) the effects of release on pine growth. The pine release treatment did not enhance stand development during the 9 yr rehabilitation period, primarily because only 18% of the pines (representing 5% of total pine basal area) were overtopped by hardwoods and were thus in need of release. However, results suggest that stands having an initial stocking of 20 to 30%, or a total basal area of 10 to 15 ft2/ac, can reach an acceptable stocking (levels of 60% for stocking, 45 ft2/ac for basal area, and 2,500 bdft(Doyle)/ac for sawlog volume) within 1.5 yr or less. SoHth. J. Appl. For. 22(1):47-52. Many acres of commercial timberland in the South are understocked (less than 60% stocking) with desirable species because of opportunistic harvesting practices, natural catastrophes, or general lack of management (USDA Forest Service 1988). Sometimes, understocked stands are the result of the recent removal of much of the merchantable pine component. Techniques for rehabilitating and managing recently cutover stands have been previously discussed by Baker and Shelton (1998). Often, however, understocked stands are the result of harvest operations that occurred 10 to 15 yr previously with failure to regenerate or manage the residual stand. This type of understocked stand condition may be more difficult to rehabilitate because of the advanced development of hardwoods on the site when pines are the preferred crop trees. NOTE: Manuscript received July I, 1996, accepted March 3, 1997. James Baker is the corresponding author and can be reached at (870) 367. 3464; Fax (870) 367-l 164. This research was done in cooperation with the Mid-Continent Division of Georgia-Pacific Corporation on lands owned by Bob and Ruby Lanier, Lake Village, AR. Use of trade names is for reader information and does not imply endorsement by the U.S. Department of Agriculture to the exclusion of any suitable product or process. All uses of pesticides must be registered by appropriate state and/or federal agencies before they can be recommended. This study was installed in a cutover, understocked, uneven-aged loblolly-shortleaf pine (Pinus taeda L.-P. echinata Mill.) stand to determine (1) the rate at which the understocked stands, that were cutover 10 to 15 yr previously, recovered, (2) the minimum stocking level required for successful rehabilitation, and (3) if the release of pines from overtopping hardwoods would enhance pine growth. A stand would be considered adequately stocked orrehabilitated when itreached 45 ft2/ac of basal area, or 2,500 bd ft(Doyle)/ac of sawtimber volume (Baker et al. 1996), or 60% stocking (USDA Forest Service 1972).