Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> Many alternative approaches have been proposed for setting conservation priorities from a database of species (or communities) by site. We present a model based on the premise that reserve selection or site prioritization can be structured as a classic covering problem commonly used in many location problems. Specifically, we utilize a form of the maximal covering location model to identify sets of sites which represent the maximum possible representation of specific species. An example application is given for vertebrate data of Southwestern California, which is then compared to an iterative solution process used in previous studies. It is shown that the maximal covering model can quickly meet or exceed iterative models in terms of the coverage objective and automatically satisfies a complementarity objective. Refinements to the basic model are also proposed to address additional objectives such as irreplaceability and flexibility. <s> BIB001 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> This is an overview of operational research work that has been carried out to support strategic forest management planning, short term forest planning, forest operations, and forest fire management. It identifies important unresolved problems and new challenges that could serve as a rich source of problems for both practitioners and researchers. <s> BIB002 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> The problem of designing a natural area reserve for the preservation of species is approached as a zero-one integer program. The least-cost assemblage of parcels is sought for different numbers of species whose locales must be included within the reserve. The reserve itself is designed to include core parcels and buffer parcels which surround and protect the core. Compactness and contiguity of the reserve are promoted by the problem formulation. Solution is by a combination of a greedy heuristic followed by heuristic concentration which achieves a reduced set of variables for the zero-one program. <s> BIB003 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> Forest resource use has traditionally been multifaceted. In order to ensure that these resources continue to be available for use by current and future generations, sustainable management practices are essential for striking a balance between the varied and often competing demands associated with forest use. This has meant that analysis incorporate specific objectives and considerations aimed at minimizing the impacts of forest activities. One such management planning approach has been the inclusion of spatial restrictions in harvest scheduling analysis. This article reviews two basic harvest scheduling models which may be used for imposing spatial restrictions. Distinctions between the alternative methods are highlighted and operational considerations are discussed. This article establishes and outlines priority areas for future harvest scheduling research. <s> BIB004 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> Both in New Zealand and Chile there exist important forest industries based mostly on pine plantations. The management of harvesting requires a series of activities such as building access roads, harvesting with skidders on flat terrain and cable logging for steep terrain, transportation from forest origins to destinations, such as a port, pulp plant and sawmills. <s> BIB005 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> Preface1. IntroductionPart I. Simple Proximity Relationships2. Sedimentation3. Stormflow Management4. Natural Regeneration in Any-aged Forest Management5. Combining Simulation with Optimization: Habitat Placement for the Northern Spotted OwlPart II. Reaction-Diffusion Models6. Characteristics of the Discrete Reaction-Diffusion Model7. The Basic Model: Habitat Placement for the Black-Footed Ferret8. Population-Dependent Dispersal: Habitat Placement for the Black-Tailed Prairie Dog9. Topography-Based Dispersal: Habitat Location for the Western Prairie Fringed Orchid10. Habitat Edge EffectsPart III. Control Models11. Strategies for Controlling Exotic Pests12. Strategies for Controlling WildfirePart IV. Using Optimization to Develop Hypotheses About Ecosystems13. Multi-Scaled Ecological Limiting Factors14. Carbon Fixation in Trees as an Optimization Process15 PostscriptReferencesIndex <s> BIB006 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> Because of environmental concerns, modern forest harvesting plans are being modified to address aesthetics and wildlife protection issues. In the literature, the most referenced are adjacency constraints with exclusion or greenup years. Also of interest are the concepts of old growth patch size and total old growth area restrictions. Typically, harvest blocks have been defined a priori. Recently, some have proposed a more complex approach in which basic cells are defined, and the decision-making process includes forming harvest blocks from these cells. This has been called ARM (Area Restriction Model). Until now, no successful exact method has been reported for large-scale ARM problems, leaving heuristics as a viable option. In this work we present a multiperiod harvest-scheduling ARM model with these spatial constraints. A tabu search procedure with 2-Opt moves (exchanging at most 2 units) was developed. For small size instances, the procedure found the optimal solution in most cases, and for a real-size problem an 8% optimality gap is provided. <s> BIB007 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> Abstract Production of marketed commodities and protection of natural systems often conflict. A focus on only one goal can result in large losses in other goals and may result in inefficient and unsustainable outcomes. In this paper, we develop a method that combines economic and ecological models in a dynamic and spatial analysis to evaluate land use decisions and find cost-effective alternatives for which it is not possible to do better on one objective without harming another objective. The method is demonstrated using timber production and species conservation on a forested landscape over a 100-year planning horizon. Current land use strategies are simulated and compared with cost-effective alternatives. The approach is compared to a static reserve approach, similar to previous studies, and found to produce substantially more efficient management strategies for the case study landscape. <s> BIB008 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> We consider a spatial problem arising in forest harvesting. For regulatory reasons, blocks harvested should not exceed a certain total area, typically 49 hectares. Traditionally, this problem, called the adjacency problem, has been approached by forming a priori blocks from basic cells of 5 to 25 hectares and solving the resulting mixed-integer program. Superior solutions can be obtained by including the construction of blocks in the decision process. The resulting problem is far more complex combinatorially. We present an exact algorithmic approach that has yielded good results in computational tests. This solution approach is based on determining a strong formulation of the linear programming problem through a clique representation of a projected problem. <s> BIB009 </s> Operations Research Models and the Management of Agricultural and Forestry Resources: A Review and Comparison <s> The Environmental Question <s> An important issue being discussed for Chilean pine plantation policies is the application of environmental protection measures when managing its timber areas. Typical measures, already in place in more developed countries, include imposing riparian strips and protecting fragile soils from the use of heavy machinery. While environmental protection measures have been considered vital for decades, so far there has been almost no attempt to quantify both the benefits and costs of these measures. This paper attempts to measure the costs associated with the main measures which can help both the forestry firms and the government evaluate the cost impact of the new environmental protection regulations being studied. The analysis for different environmental scenarios is carried out by modifying a mixed integer LP, currently used for tactical planning by one forestry firm. <s> BIB010
Because of environmental issues, forest managers must consider increasingly stringent conditions: (1) The amount of habitat protected requires decisions on which areas to leave unharvested in a compromise between economic and wildlife-protection goals. This problem can be defined as the minimal reserve set, that is, what is the minimal number of areas to reserve to ensure that each protected species is represented in at least one reserved area BIB003 . BIB001 developed a maximalcovering-location problem to identify sets of sites to best represent specific species.  and Rosing and ReVelle (1986) showed how to use OR models to solve the reserve-selection problem. Because different species require different habitat types defined by levels of growth of trees (or seral stages), this specification is a simplification of the real problem. (2) Habitat patches or areas with no grown trees can have both minimum or maximum area constraints. Planning for them matches the so-called adjacency problem, where no two adjacent cutting units in a forest can be harvested in the same period. Cutting units typically measure about 40 hectares. This leads to a chessboard pattern, where only the white cells can be harvested in a single period. Analysts can model this hard combinatorial problem as a 0-1 integer problem but can solve only moderate size problems using conventional branch-and-bound algorithms. North American and European forest management typically includes these constraints. In actual applications, analysts are using heuristic approaches, such as tabu search, simulated annealing, and Monte Carlo simulation BIB002 . They have proposed exact approaches for solving the adjacency problem, including strengthening the LP formulation using LP column generation coupled with heuristics  , clique representations of adjacency  , and dynamic programming  . In the last few years, analysts have been seeking ways to better define the cutting units. Foresters form cutting units of 40 hectares from basic cells of five to 20 hectares through GIS-assisted analysis. BIB004 showed that they could improve solutions by taking one step back and introduce the building of cutting units into the decision models.  have solved large instances of the resulting complex combinatorial problems using local search heuristics only. BIB009 have solved medium-sized problems of up to 1,300 cells with models of 10,000 to 15,000 0-1 variables by strengthening the LP formulations. Foresters must provide large blocks of old trees for some animal species or establish corridors between patches, problems which have typically been approached via metaheuristics BIB007 . Downloaded from informs.org by [200.89.69 .180] on 20 July 2015, at 12:33 . For personal use only, all rights reserved. (3) The movement of wildlife species and their dispersion over time (a way of controlling population) require corridors of mature trees between feeding areas BIB006 . Typical problem-solving procedures include linear and nonlinear programming, integer programming, heuristics, and Monte Carlo simulation. (4) Forest edges juxtapose trees of different ages, which many species require for cover, feeding, and foraging. Such species cannot travel far through unbroken forest without eating. Water quality is also important; harvesting operations cause warming and increase sediment. The algorithms and systems developed for these problems rely on GIS linkages to databases and heuristic approaches. Analysts are investigating more complex approaches, such as the use of 0-1 LP models for wildlife habitats or edge effects. In managing plantations, foresters have used models to evaluate the costs of implementing environmentally sensitive harvesting policies, such as not using heavy machinery on fragile soils or leaving riparian strips to avoid polluting rivers BIB005 BIB010 . BIB008 combined a wildlife-simulation model and an optimization model and used a heuristic algorithm to obtain efficient solutions and analyzed the trade-offs between timber production and preservation of two animal species. This approach proved superior to analyzing each aspect separately. The increasing severity of international-environmental-certification processes compel foresters to cope with environmental issues and will provide analysts with modeling challenges. Analysts have developed decision-support models to help foresters understand and control forest fires. They have used simulation to estimate fire propagations and LP and 0-1 LP models to support decisions on fire prevention and short-term suppression operations BIB002 ).