Considering Overhead Costs in Road and Landing Spacing Models
Authors
Michael A. Thompson
USDA Forest Service Houghton, USA
Abstract
Existing road and landing spacing models assume that spacing affects only the costs of road construction and skidding. However, costs that are independent of production and fixed on the basis of time will vary with spacing when specified on a "per-unit-volume produced" basis and therefore should be considered in the model. Costs of this nature are labeled overhead, and considering these costs in the model will lower total costs. The relationship of overhead costs to spacing follows the same pattern as the skidding costs and can be added to the cost of owning and operating the skidder in the model. Overhead costs were considered in models pertaining to three unique sets of conditions: skidding to roadside with a single road standard; skidding to roadside with two road standards; and skidding to a landing. In all cases, considering overhead in the model lowered total cost and reduced road spacing. Actual cost savings will depend on harvest conditions but can be significant.
