Results of a Long-term Thinning Study in Some Natural, Even-aged Pine Stands of the Midsouth

This paper reports on a long-term thinning study established in stands of naturally seeded loblolly (Pinus taeda L.) and shortleaf (P. echinata Mill.) pine in southern Arkansas and northern Louisiana. Plots were established in 1949–50 and 1954 in previously unmanaged stands, thinned about once every 5 years from age 20 to 60 years (40 years of active cutting, to 1990). The study was discontinued in 1995 when the stands were about 65 years old. Low-density stands on good sites produced bigger individual pines more quickly than denser stands on medium sites. Long-term sawtimber yields did not follow this pattern, however. While medium-quality sites produced somewhat lower gross yields, denser stands ultimately resulted in significantly higher total yields, primarily because of their better stocking.