Growth and Architectural Response of Beech Seedlings to Canopy Removal and Soil Compaction from Selective Logging

Abstract

Logging operations change the forest environment by creating a heterogeneous canopy with a range of different microenvironments that differ mostly in light intensity and level of soil disturbance. In this study, the growth characteristics and architecture of beech (Fagus orientalis Lipsky) seedlings grown in three different microenvironments in terms of canopy and soil conditions were investigated. The experimental treatments (microenvironments) included skid trail (removal of canopy and compacted soil), winching corridor (natural canopy and compacted soil), felling gap (removal of canopy and natural soil), and comparison with the control area (canopy and soil in natural state). The results showed that the status of many growth and architectural indicators of seedlings is significantly less favorable than in the control area. These indicators include the length and biomass above and below ground, and the ratio of root length to stem length in the skid trails and winching corridors. The status of these indicators was, however, more favorable in felling gaps than in the control area. The seedling quality index decreased by −12.2% and −4.9% in skid trails and winching corridors, respectively, but increased by 2.4% in felling gaps compared to the control area. The growth characteristics and biomass of seedlings had a significant negative correlation (p < 0.01) with soil bulk density and penetration resistance and a significant positive correlation (p < 0.05) with soil porosity, moisture, and organic matter content. These results showed that the creation of a gap in the stand canopy due to the cutting of individual trees created a favorable micro-environment for the growth of seedlings, but the soil compaction caused by logging operations created an unfavorable micro-environment for these. Therefore, it is necessary to plan and execute the operation of extracting the cut trees in such a manner as to reduce the extent and severity of soil compaction with the goal of preserving and maintaining the stability of the forest ecosystem.