Partial Harvest Effects on the Forest Floor at Four Northern Hardwood Sites in the Green Mountains of Vermont, USA

Abstract

Harvesting activities are known to decrease forest floor carbon pools, but the response varies with harvest intensity. We examined partial harvesting (33–55% of basal area removed) effects on the forest floor at four northern hardwood sites in Vermont, USA. Six baseline quantitative samples were taken at each site and 9–36 new locations were sampled 1.5–2.6 years after harvesting. Forest soil disturbance was estimated, and basal area was tallied pre- and post-harvest. The forest floor consisted primarily of Oi and Oe horizons. The pre-harvest site means in carbon stock ranged from 6.8 to 12.3 Mg ha-1 and were not significantly different after harvesting. The pre-harvest site means in depth ranged from 2.8 to 4.5 cm and, post-harvest, there was significantly decreased thickness at one site and significantly greater density at two sites postharvest. This compaction was also visually observed in the field. Partial harvesting, which included single-tree and group selection, created highly variable conditions that challenged our experimental design. However, the two sites with the higher number of resampling locations (35–36) had relatively low variability in forest floor metrics and showed significant responses in thickness and density. Continued monitoring is needed to determine long-term trends.

Land use change and forest management effects on soil carbon stocks in the Northeast U.S.

“…Increasingly, the soil C literature is turning in this direction, with studies addressing more prevalent treatments such as single- and group-tree selection, crop tree release, various types of thinning, and shelterwood harvests. Two recent partial harvest studies, both in northern hardwoods, provide several nuanced insights that help advance the clearcutting-biased literature on this topic [ 83 , 84 ]. First, neither of these studies detected significant changes in total organic horizon C stocks (though Puhlick and Fernandez [ 83 ] reported fine-fraction O horizon declines).…”

“…First, we incorporated bulk density (Db) as a specific response parameter of interest. Second, in several cases, we directly contacted study authors to obtain data not reported in, but underpinning several forest harvest papers from the region [ 73 , 83 , 84 , 87 , 88 ]. These personal communications were necessary to bring summarized data from these important regional papers to the same level of site-specific detail found in the majority of other forest harvest papers (or their associated Additional file 2 : Datasets).…”