Loblolly Pine Stand Early Development Under Reserve-Tree Silvicultural Systems in East Texas

Even-aged reproduction methods retaining reserve trees that persist through the development of the succeeding rotation have been poorly studied in loblolly pine (Pinus taeda L.), yet have potential for satisfying a variety of landowner objectives. Two research sites were established in the East Texas Pineywoods region to examine the development of the regeneration component under five residual basal area densities (0, 10, 20, and 40 ft2/ac with natural regeneration on Site I; 0 and 30 ft2/ac with both natural regeneration and planting on Site II). After 7 yr on Site I and 5 yr on Site II, all reserve-tree methods allowed the development of a sufficient number of trees for producing a new generation beneath the residual overstory. However, suppression of the understory pines was evident, and varied in direct proportion to the basal area of the residual overstory. Volume growth of the residual overstory trees was low on an areal basis due to the death of several large residuals. A trenching experiment showed that the largest effect of the residual overstory on understory development was due to light attenuation rather than competition for soil resources. Advantages offered by reserve-tree methods for loblolly pine have to be assessed in view of the suppressed development of the regeneration. South. J. Appl. For. 24(1):11-16.