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Strategic business plans are based upon assumptions of future wood costs. Future wood costs are affected by future equipment cost inputs and technological change. Equipment replacement decisions re...

In this work, we present a model to assist in the equipment replacement decision process in the context of the Brazilian forestry sector using detailed equipment maintenance schedules. The approach...

This paper presents a solution for a three-stump anchor system using a continuous bridle and assuming frictionless blocks. This solution is unique in that the location of the bridle block is not kn...

For a limited set of conditions we have shown that recovering braking energy from log trucks descending from high elevation stands to lower elevation manufacturing facilities can reduce the size of the battery required to run a log truck. Adding level highway hauls after descending from the higher elevation stands quickly increases the required battery capacity. The effect of conversion efficiency on the required battery capacity is correlated with the change in elevation along the haul route. At a conversion efficiency of 100% (battery-to-wheels and wheels-to-battery), the cumulative battery usage on the base profile (elevation factor = 1.0) is only one-half of what it would have been compared to a level road of the same horizontal length (elevation factor = 0.0). When the conversion efficiency is set to 60%, the cumulative battery usage for the base profile would be the same as if the truck had been on a level road of the same horizontal distance. For the actual haul route considered in this pap...

Cable yarding systems are a common method for transporting materials in mountainous terrain in situations that do not allow for ground-based skidding, forwarding or shovel-logging. Cable yarding, although effective in steep locations, requires anchored guylines to support the skyline and operating lines. The skyline and operating lines rely on a fixed anchor, or tailhold, to provide adequate tension for effective yarding. Anchored guylines and skylines usually depend on available stumps or trees. Where these are not available, mobile anchors such as bulldozers can be used. Mobile equipment anchors have an advantage of known resisting capacity, as opposed to trees and stumps, but there are no well-defined design criteria for the application of the system. Here an analytical design solution for mobile anchor capacity is presented, based on force equilibrium analyses, and accompanied by a series of design charts. A moment equilibrium analysis involving vehicle center of gravity and anchor attachment points i...

This research investigates an economic component of harvesting operations not previously studied for steep-slope thinning harvests in Douglas-fir (Pseudotsuga menziesii) stands. Pacific Northwest log manufacturing was explored to evaluate revenue improvement through bucking-to-value strategies. A previous study evaluated a reduced set of log lengths that approach computer-generated optimal values and the potential for development of a bucking decision tool for field crews. This study sought value optimization with a log-allocation constraint through the application of a simulated annealing (SA) heuristic approach for the reduced set of log lengths to create the bucking pattern cutting instruction card. A reduced set of five log lengths (two mill-length logs and three woods-lengths resulting from combinations of the mill lengths) was evaluated for value recovery. Resulting values obtained 96 and 98% of full set optimal values for 45- and 65-year-old stands, respectively. Value recovery exceeded current una...

Cable yarding has been used for many years in mountainous forests in central European countries. Tower yarders are common cable yarding systems in Austria. The goal of this study was to develop a general time prediction model for two kinds of tower yarders used in Austria. The multiple regression method was applied. The average production rate was 9.30 m3/PSH0 with a cost of US$25.48/m3. The results also showed that the production rate for downhill yarding was less than uphill yarding using the Syncrofalke tower yarder. The developed time production models can help forest engineers estimate production of tower yarders in similar logging operations.

Road grading is the most common maintenance activity performed on forest roads. Reducing grading cost could release resources for other maintenance needs, ideally resulting in a better maintained road system. A combinatorial optimization method, tabu search, is combined with two local search procedures to generate efficient grading routes. Determining the optimal grading route is modeled as an extension of the Mixed Rural Postman Problem (MRPP), adapted to include a daily operating time limit and different traversal/service times. The objective was to minimize total operating time, a proxy for grading cost. The heuristic was tested on both artificial and actual forest road networks, and computational results are presented. The heuristic demonstrates the ability to generate efficient and feasible grader routes.

A previous study introduced a forest road design model developed to simultaneously optimize horizontal and vertical alignments of forest roads using a Tabu Search optimization technique and a high-resolution Digital Elevation Model (DEM). In this study, surface erosion prediction was incorporated into the road design model, so that users can optimize horizontal and vertical alignments of forest roads while constrained by maximum allowable sediment delivery from roads to streams. The road alignment optimization model was applied to a part of the Capitol State Forest in western Washington state. The application confirms the potential of the model to determine forest road alignments in a way to reduce total road costs as well as sediment delivery to streams. This paper also discusses the effects of DEM resolution on forest road alignment optimization. The accuracy of generating ground profile and forest road alignments depends on the resolution and accuracy of the DEM. The study results suggest that...

The prioritization of road maintenance projects is an important forest engineering task due to limited budgets and competing investment needs. Large investments are made each year to maintain and upgrade forest road networks to meet economic and environmental goals. Many models and guidelines are available for single-criteria analysis of forest roads, however we have found no method for multi-criteria analysis. Additionally, even single criteria approaches often rely on expert judgment to inform models of user preferences and priorities. These preferences are used to make tradeoffs between alternatives that contain data that are physical and biological, quantitative and qualitative, and measured on many different scales. The Analytic Hierarchy Process (AHP) has the potential to provide a consistent approach to the ranking of forest road investments based on multiple criteria. AHP was specifically developed to provide a consistent, quantifiable approach to problems involving multi-criteria analysi...

Shovel logging has become a popular logging system in the western United States due to its high productivity. Its low ground pressure and single pass, often on a matt of limbs result in little ground disturbance. Despite this increasing popularity, there have been few operational studies of shovel logging. This paper describes the optimal road spacing problem for shovel logging using a serpentine pattern on gentle terrain. A mathematical model for shovel logging is presented for two cases (1) to minimize the sum of shovel yarding costs plus road costs from the landowner’s point of view and(2) to maximize profits from the point of view of a logging contractor. For the operating conditions assumed, the optimal shovel yarding distance is four swings when shovel yarding plus roads costs are minimized and three swings when logging contractor profit is maximized. For the example data, the model results demonstrate the flexibility of shovel logging in that there is little difference between total road c...

In order to locate a path between two known locations on a ground surface, a large number of alternative paths should be evaluated considering physical, economical, and environmental factors. Optimization techniques can be used to search for a path that minimizes the total costs while satisfying the design and environmental constraints. These techniques can result in considerable time savings in forest road design. Initially, these optimization techniques have been applied to highway design and recently, they have been applied to forest road design. This paper describes the evolution of the optimal route location systems used in both highway and forest road design based on ten criteria. The paper concludes by describing some of the unsolved problems in forest road design.

We developed a forest road design model that simultaneously optimizes horizontal and vertical alignments of forest roads using a high resolution Digital Elevation Model (DEM). Once an initial horizontal alignment is established by locating a series of intersection points, the model generates alternative horizontal and vertical alignments and cross sections along the road prism. The model also estimates earthwork volume and construction and maintenance costs for given road alignments and their spatial locations. The model then optimizes road alignments based on construction and maintenance costs using Tabu Search, one of the modern heuristic techniques. The model was applied to a part of Capitol Forest in Washington State, USA, where a high resolution DEM derived from LiDAR (Light Detection and Ranging) data was available. First, the program generated an initial horizontal alignment with the length of 827m and five horizontal curves based on manually selected intersection points. Then, the vertica...