Impact on Soil Physical Properties Related to a High Mechanization Level in the Row Thinning of a Korean Pine Stand

Abstract

In ground-based harvesting, machine traffic can cause soil physical disturbances including excessive compaction, the displacement of the soil surface and topsoil, and rutting. These impacts can indirectly hamper seedling survival and tree growth because of reduced soil permeability and root growth. However, the extent of soil disturbance in mechanized row thinning by harvester and forwarder systems in South Korea is unclear. Therefore, our objectives were to determine the impacts of two types of harvesters, soil textures, and extraction methods on soil compaction and rutting in a Korean Pine stand. The results showed that the machine passes affected soil disturbances. The soil bulk density inside the tracks (at 0–10 and 10–20 cm soil depths) after harvester passes (wheeled vs. tracked) increased by 17 and 27% and 30 and 20%, respectively. The largest impact was recorded for the forwarding track and significant differences were observed between the track and reference locations. Furthermore, the rutting depth in the forwarding trails was significantly higher than in the harvester trails. Thus, the application of a brush mat on harvester and forwarder trails may reduce machine-induced soil compaction. These results provide useful information to help forest engineers and field managers design environmentally sound ground-based harvesting operations.

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

“…In recent years, the mechanized row-thinning application, which uses a harvester and forwarder, has resulted in increased productivity and work safety [20]. For example, Hwang et al [6] reported that although mechanized thinning is an effective tool to control overstocked stands and restore ecosystems, it can possibly expose the remaining damage to the stand.…”

Assessing the Extent and Severity of the Impact on Forest Soils of Two Different Fully Mechanized Timber Harvesting Operations

“…Timber is felled and extracted using various technologies with different levels of mechanization, including fully mechanized, semi-mechanized, and motor-manual methods [1,2]. Even though mechanized harvesting technologies can provide clear benefits by improving productivity and safety, ground-based machine traffic can inherently impact forest ecosystems, particularly forest soils [3][4][5] in the form of compaction, rutting, and displacement [6,7]. The severity and extent of soil disturbance during mechanized operations depend on several factors such as the harvesting system, silvicultural treatments, terrain slope, soil type, and texture [3,8].…”

“…Recently, mechanized operations involving harvesters and forwarders on both gentle and steep terrains have led to increased productivity but fewer job opportunities for loggers in South Korea (hereafter, Korea; [16]). A harvester-forwarder system can replace manual tree felling, processing, and shovel and cable extraction; however, mechanized operations are more likely to cause severe soil disturbances [3,7,17]. Several investigations on soil disturbance related to cut-to-length systems in Korea have examined conventional chainsaw felling and small-shovel extraction, as well as mechanized harvesting systems, such as harvester-forwarder operations [7,18].…”

“…A harvester-forwarder system can replace manual tree felling, processing, and shovel and cable extraction; however, mechanized operations are more likely to cause severe soil disturbances [3,7,17]. Several investigations on soil disturbance related to cut-to-length systems in Korea have examined conventional chainsaw felling and small-shovel extraction, as well as mechanized harvesting systems, such as harvester-forwarder operations [7,18]. However, comprehensive research on the degree of detrimental soil disturbances-including visual, physical, and hydrological effects-caused by ground-based cut-to-length (CTL) and whole-tree (WTH) systems remains insufficient.…”