Impacts caused by the traffic of ground-based forest harvesting machinery: State of the art and future guidelines for Chile

The most frequently reported impacts of timber harvesting operations are on the soil and are mainly concentrated along skid trails and other areas of high traffic. Research addressing the impacts of ground-based harvesting machinery varies widely and is predominantly composed of case studies, which makes its application to other environmental contexts difficult. Considering the importance of the Chilean forest sector, the diversity of sites, and operational conditions in the country, as well as the predominant existence of plantations managed as short-rotation forest crops by clearcutting, it is paramount to identify the state of the art in Chile and knowledge gaps. To this end, environmental impacts and associated best management practice recommendations were identified based on 252 studies from 31 countries through a systematic search of articles in reference databases. The results highlight the under-studied geographical areas and soil types worldwide. The main disturbance reported were related to soil physical properties, followed by disturbance to the flora structure and composition, chemical properties, hydraulics, and soil biological properties. Seven general recommendations were identified and discussed regarding best management practices. Common recommendations include preventive measures to reduce soil impacts. In the case of studies conducted in Chile, only one indexed article (<0.01 %) was found, which raised the need to expand the search to national databases where five additional articles were found. This review is consistent with international study results. However, there is a recognized lack of knowledge regarding forest soils, types of disturbance, and the environmental impacts of modern harvesting machinery. Additionally, gaps in research related to skid trail planning alternatives, soil monitoring, and recovery times have been identified. Research needs related to these knowledge gaps have been proposed.