A Spatially Explicit Method to Assess the Economic Suitability of a Forest Road Network for Timber Harvest in Steep Terrain

Leo Gallus Bont,Marielle Fraefel,Christoph Fischer

doi:10.3390/f9040169

Leo Gallus Bont, Marielle Fraefel + Show 1 more

Open Access

https://doi.org/10.3390/f9040169

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Abstract

Despite relatively high road density in the forests of Switzerland, a large percentage of that road network does not fulfill best practice requirements. Before upgrading or rebuilding the road network, harvesting planners must first determine which areas have insufficient access. Traditional assessment methods tend to only report specific values such as road density. However, those values do not identify the exact parcels or areas that are inaccessible. Here, we present a model that assesses the economic suitability of each timbered parcel for wood-harvesting operations, including tree-felling and processing, and off- and on-road transport (hauling), based on the existing road network. The entire wood supply chain from forest (standing trees) to a virtual pile at the border of the planning unit was captured. This method was particularly designed for steep terrain and was tested in the Canton of Grisons in Switzerland. Compared with classical approaches, such as the road density concept, which only deliver average values, this new method enables planners to assess the development of a road network in a spatially explicit manner and to easily identify the reason and the location of shortcomings in the road network. Moreover, while other related spatially explicit approaches focus only on harvesting operations, the assessment method proposed here also includes limitations (road standards) of the road network.

Highlights

For the efficient management of a forestry system, especially the harvesting and hauling of timber, a state-of-the-art forest road system is required
Classical approaches to assessing road networks in terms of timber production have been based on the “optimum road spacing/optimum road density” concept of Matthews [2]
TPs identified as unsuitable do not necessarily require better development; the result indicates they are not ideal for timber production. This new spatially explicit method was designed to assess the suitability of a forest road network for economical timber production

Summary

Introduction

For the efficient management of a forestry system, especially the harvesting and hauling of timber, a state-of-the-art forest road system is required. Those roads should accommodate large trucks, such as five-axle or 40-ton trucks in the case of Switzerland. Considering the various costs for on- and off-road transport as well as those for road construction, Matthews determined the road spacing for minimum overall costs This approach was further expanded by Sundberg, Segebaden, Abegg, Thompson, and Heinimann [3,4,5,6,7] this concept of “optimum road density”

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