Distribution of Slash and Litter After Wet- and Dry-Site Harvesting of Loblolly Pine Plantations

Abstract

Displacement of logging slash and forest floor litter in the process of harvesting can interfere with forest nutrient cycling and can modify soil climate in ways that could affect regeneration success and forest productivity. The objective of this study was to assess a visual method for estimating organic matter and slash biomass residues following a typical feller-buncher/grapple-skidder clearcut harvest. A 20 by 20 meter grid was established in six 20-year-old loblolly pine plantations, each of which was 3.2 ha in size. Pre-harvest biomass was estimated using biomass equations developed by Baldwin (1987). Post harvest slash and litter biomass remaining was measured across the grid network by making visual estimates of percent coverage for each of 4 size classes and relating that to biomass using simple linear regression. Harvest slash and litter were collected from 4 m² plots and weighed to estimated biomass as a function of percent cover for each size class. Heavy slash (> 2.5 cm) on the wet harvest sites had a biomass of 2.49 kg/m², compared to 1.89 kg/m² on the dry harvest sites. The amount of light slash (c 2.5 cm) was also significantly greater on the wet harvest sites, 2.47 kg/m², compared to that on the dry-harvested sites at 1.99 kg/m2. Litter biomass, -2.4 kg/ m², and piles, 0.7 kg/m², were not significantly different between sites. Visual estimation procedures provide a rough but useful estimate of biomass remaining after harvest (R² = 0.42 to 0.67), an extensive spatial estimate that is difficult to ascertain in any other way. The method reveals a certain amount of homogenization after harvesting. Harvesting sites when dry compared to wet results in a larger amount of displacement from the interior of a logging site. These estimates can be used to judge whether harvesting disturbance on organic residues affects stand productivity.

Citation

Eisenbies, Mark H.; Burger, James A.; Xu, Yi-Jun; Patterson, Steve. 2002. Distribution of Slash and Litter After Wet- and Dry-Site Harvesting of Loblolly Pine Plantations. In: Gen. Tech. Rep. SRS–48. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pg. 510-514