Soil and Residual Stand Disturbances after Harvesting in Close-to-Nature Managed Forests

Abstract

Close-to-nature forestry is a viable option to manage forests that are resilient to the challenges presented by climate change. The new silvicultural schemes necessitate adapting the operational side, posing challenges to productivity and the environmental effects of harvesting machinery and technologies. This study focused on analysing the disturbance of residual stands and forest soils in stands that were being restructured into multistorey, close-to-nature managed ones using low-impact forest harvesting technologies. Measurements were performed in four stands after logging, divided into 30 sample plots with dimensions of 20 × 20 m. Within the plots, the disturbance of the residual stands and changes to the soil parameters, such as the soil bulk density (g·cm−3) and soil penetration resistance (MPa), were measured. The results showed that the intensity of the residual stand disturbance reached between 13% and 23% and was not significantly (p > 0.05) affected by the intensity of the performed harvesting operations. The mean size of the wounds was between 38.99 and 233.05 cm2, and wounds were most frequently in the size category of 11–50 cm2. Regarding soil disturbance, Spearman’s correlation showed a significant relationship (p ˂ 0.05) between the longitudinal slope and soil bulk density in the rut of the trail. The relative increase in BD showed that the largest increase occurred between the stand (undisturbed) and rut locations (12.5% to 24.77%). Penetration resistance measurements were affected by low moisture content and high coarse fragment content. Subsequently, Spearman’s correlation did not show (p > 0.05) a relationship between the soil bulk density and penetration resistance. Therefore, we can conclude that, from an environmental perspective, the proposed technologies are viable options for foresters who manage close-to-nature forests, and there was less disturbance of residual stands and forest soil caused by harvesting machinery.

Assessing the Residual Stand Damage after Thinning with Different Levels of Mechanization

“…Our results provided that the damage frequency was lower for the mechanized row-thinning, compared to the manual thinning. Similar results were obtained by Magagnotti et al [23]. Akay et al [24], Cudzik et al [5], Kizha et al [7], and Suhartana et al [25] reported that the most damage occurs during tree felling and extraction by machine traffic and log dragging and loading from the stump to the landing.…”

“…Trees less than 6 cm at DBH were rejected from the damage measurements. In addition, all injury sizes for the roots, bu s, and stems were assigned a severity index of 1-6 to assess the level of wound severity: 1 = negligible injury, damaged area below 10 cm 2 ; 2 = very light, damaged area of 50 cm 2 ; 3 = light, damaged area of 100 cm 2 ; 4 = medium, damaged area of 200 cm 2 ; 5 = heavy, damaged area of 300 cm 2 ; and 6 = very heavy, damaged area above 300 cm 2 [23]. In addition, all injury sizes for the roots, butts, and stems were assigned a severity index of 1-6 to assess the level of wound severity: 1 = negligible injury, damaged area below 10 cm 2 ; 2 = very light, damaged area of 50 cm 2 ; 3 = light, damaged area of 100 cm 2 ; 4 = medium, damaged area of 200 cm 2 ; 5 = heavy, damaged area of 300 cm 2 ; and 6 = very heavy, damaged area above 300 cm 2 [23].…”