Cost comparison of non-frozen and frozen forest road construction in changing climates

Abstract

ABSTRACT In many northern forests, the preferred time of harvesting is when the ground is frozen. Logging activities on frozen ground reduce the cost of forest operations by allowing heavier loads on temporary roads and makes crossing wetlands feasible. Increased winter temperature and more frequent winter thaws decrease the period of frozen ground conditions. In order to adapt to shorter periods of frozen logging season, forest companies might have to access frozen harvesting sites in the non-frozen season. In this study, we examined the cost of temporary forest road construction in terms of switching logging activities from frozen to non-frozen conditions. The objectives were to estimate the costs of non-frozen temporary roads for four harvesting units with different difficulty of access. We also analyzed construction costs for both frozen and non-frozen access under possible different wetter and drier scenarios. The results show that the average cost of temporary road construction increased from $1,200 km−1 or $0.30 m−3 in frozen conditions to $5,962 km−1 or $2.14 m−3 in non-frozen conditions. Under the extreme wet scenarios, the cost of non-frozen roading ($ m−3) of the unit with the most difficult access was up to 14.6 times more than frozen road construction. If the soil dried faster than the base case scenario, cost increases of non-frozen road construction ($ km−1) were expected to be between 2.3 times and 8.6 times more than the frozen road construction cost, depending upon the difficulty of accessing the unit.