Assessing the impacts of log extraction by typical small shovel logging system on soil physical and hydrological properties in the Republic of Korea

Eunjai Lee; Qiwen Li; Song Eu; Sang-Kyun Han; Sangjun Im

doi:10.1016/j.heliyon.2020.e03544

Assessing the impacts of log extraction by typical small shovel logging system on soil physical and hydrological properties in the Republic of Korea

Heliyon. 2020 Mar 10;6(3):e03544. doi: 10.1016/j.heliyon.2020.e03544. eCollection 2020 Mar.

Authors

Eunjai Lee¹, Qiwen Li², Song Eu², Sang-Kyun Han³, Sangjun Im⁴

Affiliations

¹ Forest Technology and Management Research Center, National Institute of Forest Science, Pocheon 11186, Republic of Korea.
² Department of Forest Sciences, Seoul National University, Seoul 08826, Republic of Korea.
³ Department of Forestry, Korea National College of Agriculture and Fisheries, Jeonju 54874, Republic of Korea.
⁴ Department of Forest Sciences and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea.

Abstract

Typical small shovel logging system, using manual felling and extraction by small crawler excavator with grapple and crawler carriers, is the predominant logging method in the Republic of Korea, due to the associated high productivity. The trails with ground pressure and one more passes of the shovel and carriers may lead to soil compaction. However, impacts of these bunching-extraction technologies on physical and hydrological properties of soils are not well known. The main objectives of this study were to: (1) determine the bulk density, porosity, and saturated hydraulic conductivity of soils in logging operation areas with three different disturbance types (i.e., undisturbed areas [UAs], bladed trails [BTs], and skid trails [STs]), and (2) compare soil compaction between these disturbance types. The most intense compaction occurred within BTs and STs, with increased bulk density and reduced porosity and hydraulic conductivity. Soil bulk density increased by 27-53% at all depths in BTs and STs compared to UAs, while porosity decreased by 23-49%. On average, saturated hydraulic conductivity at depths of 0-20 cm decreased from 337.5 mm h^-1 to 30.5 mm h^-1 in the most compacted sections of BTs and STs. Skid trails, which are characterized by trail construction and frequent vehicle movement, also caused greater impacts on soil compaction than BTs. This study provides useful insights to aid forest consultants and field managers in planning more environmentally sound mechanized logging operations.

Keywords: Agricultural science; Agricultural soil science; Agriculture; Environmental science; Log carriers; Porosity; Saturated hydraulic conductivity; Small shovel loader; Soil bulk density; Soil health; Soil hydrology; Soil science.