Silvicultural Prescriptions Influence the Proportion of High-Quality Hardwood Butt Logs Harvested over a Half-Century of Management

Abstract

A long-term study on the Fernow Experimental Forest (FEF) in West Virginia provided an opportunity to test for differences in the timber quality of trees harvested from three silvicultural practices (HarvestType): diameter-limit, patch cutting, and single-tree selection. The effects of HarvestType and site index (SI) over time on the harvested proportion of trees with grade 1 butt logs within a compartment were tested using a repeated-measures linear mixed model. HarvestType*Time was a significant interaction (P = 0.0018) and SI had a slight positive effect (P = 0.0036). When examining the harvested proportion of grade 1 butt logs on a volume basis, the two terms were again significant (P = 0.0003 and P = 0.0208, respectively). The diameter-limit proportion of grade 1 butt logs consistently decreased while patch cutting and single-tree selection proportions consistently increase over time. Recent preharvest cruise data show a significantly greater residual proportion of grade 1 butt logs for single-tree selection compartments versus diameter-limit compartments on a per-tree and per-volume basis (P = 0.0013 and P < 0.0001, respectively). Results indicate that the production of grade 1 trees in diameter-limit harvests is not sustainable productivity wise whereas the single-tree selection harvests are. The sustainability of the production of grade 1 logs from patch cutting remains inconclusive.