Yield comparisons from even-aged and uneven-aged loblolly-shortleaf pine stands
Empirical yields for a 36-year management period are presented for seven long-term studies on similar sites in loblolly-shortleaf pine (Pinus taeda L.-P. echinata Mill.) stands on the upper southern coastal plain of southern Arkansas and northern Louisiana. Total merchantable cubic-fooy yields are highest for conventionally managed even-aged plantations; sawtimber cubic-foot yields are highest for intensively managed even-aged plantations and intensively managed uneven-aged stands. However, uneven-aged stands have higher board-foot sawtimber yields than the most productive even-aged stands, particularly in comparisons using the Doyle log rule. It is hypothesized that the even-aged plantations have higher cubic-foot yields because they are more fully stocked with trees of merchantable size. Conversely, the uneven-aged stands have higher board-foot yields because of the greater proportion and continuous supply of sawtimber basal area, especially in stems of large size, which can be developed using the uneven-aged selection method.