Abstract
In tactical forest management planning, the decisions required to meet the strategic plan are made, and these include: i) scheduling of spatially explicit harvest-blocks; ii) construction of a road-network required to access these blocks; and iii) transportation costs within the tactical forest planning area (hereafter only referred to as transportation costs) that emerge from the first two decisions. These three decisions are interdependent and should therefore be integrated in any optimization model. At present, this integration is not fully made. This is because: i) the integrated model is NP-hard, and exact solutions are not feasible for large and medium-sized forests; and ii) metaheuristic search algorithms, which can be used on larger forests, have not integrated transportation costs realistically.The economic consequences of not integrating transportation costs into tactical planning models has not been quantified and evaluated by researchers; and the objective of this paper is to fill this gap in knowledge. To this end, an exact solution approach is used to solve and compare two integrated models: i) a model in which transportation costs are included in the objective function, and b) a model in which transportation costs are excluded from the objective function. The models were applied to three forests ranging in area from 6628 to 19,677 ha.Results show that: i) the model which included transportation costs yielded solutions with major reductions in both transportation and total costs; and ii) that, as the forests to which the model was applied tripled in area (from 6628 ha to 19,677 ha), the percent reduction in total costs increased disproportionately – more than fivefold (from 3.9% to 21%). These results are important, for they indicate that the integration of transportation costs into a tactical planning model is of major economic consequence.
Highlights
In tactical forest management planning, among others, the following decisions are made to implement the forest strategic plan: i) scheduling of spatially explicit harvest-blocks; ii) construction of a road-network required to access these scheduled blocks; and iii) transportation of the scheduled harvest of wood through the constructed road network
The candidate roads in this model do not represent individual arcs, but rather, represent a set of operational-scale arcs that are constrained to meet the horizontal and vertical design-standards of forest roads. In this model, when a polygon is scheduled for harvest, and the construction of a road is thereby triggered, the full set of operational-scale arcs, comprising that road, is triggered for construction. This approach was taken for two reasons: i) it can be useful if a tactical plan, handed down to the operational scale, contains roads that are designed to meet operational road design standards; and ii) the formulation facilitates using a dense set of candidate roads in the problem instance; and a dense set of candidate roads facilitates more alternatives by which a road network can be designed to minimize construction and transportation costs (Naderializadeh and Crowe 2018b)
The costs of transportation were either included in or excluded from the objective function as the model was applied to three forests of increasing size
Summary
In tactical forest management planning, among others, the following decisions are made to implement the forest strategic plan: i) scheduling of spatially explicit harvest-blocks (based on discounted revenue per block); ii) construction of a road-network required to access these scheduled blocks (based on discounted cost per km of constructed road); and iii) transportation of the scheduled harvest of wood through the constructed road network (based on cost per m3 per km). The two major costs resulting from tactical-level planning arise from constructing forest roads. The first major advance in modeling the tactical planning problem in forestry was based on the insight that, since the optimal locations of both cut-blocks and roads are interdependent (given an objective to maximize revenue minus cost), a model that solves both of. Naderializadeh et al On the Importance of Integrating Transportation Costs into the Tactical Forest Harvest ... Jones et al (1986) showed that solutions resulting from a model in which decisions when harvesting, road construction and transportation were integrated, resulted in 15% to 45% lower costs than the solutions generated when these decisions were made sequentially
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
