Print PageForest treatments, such as thinning, regeneration harvesting, prescribed burning, and other silvicultural activities affect the amount of leaf litter on the forest floor. The influence of these changes in leaf litter, and in turn the buildup of organic matter, on long term stand productivity, and on the cover, richness, diversity, and biomass of the ground layer vegetation (≤1.4 m in height), has not been explored extensively. We studied the impact of organic matter manipulation in a loblolly pine (Pinus taeda L.) plantation in western Alabama. The trees were planted in 1994 after clearcutting. Twelve 0.16 ha plots were established in a randomized complete block design with 3 treatments and 4 replications. The treatments were imposed after harvest and immediately before replanting. They were: 1) removal treatment - all forest floor and slash material were removed, 2) control treatment - the forest floor and slash material were unaltered, and 3) double treatment - all forest floor and slash material coming from treatment #1 (removal) was uniformly added. Tree productivity and forest floor levels were assessed. We also established 20 ground layer vegetation plots of 1 m 2 each in randomly selected locations within each 0.16 ha plot. We determined the cover of each species by visual estimation.
Results/Conclusions
Preliminary results indicated that timber volume in the double treatment was 108 m3/ha, which was 19% greater than the volume in the control (91 m3/ha) and 37% greater than the volume in the removal treatments (79 m3/ha; p<0.01). Tree survival however, was not significantly impacted by the treatment manipulations. Similarly, the forest floor mass was almost 100% greater in the doubled treatment than in the other two treatments. The effects of the organic matter treatments imposed can alter tree productivity, forest floor mass, and understory vegetation.
