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We address a multiobjective forest-management problem that maximizes harvested timber volume and maximizes the protection of species through the selection of protected habitat reserves. As opposed to reserving parcels of the forest for general habitat purposes, as most published works do, the model we present, and its several variants, concentrate on the preservation status of each one of the species living in the forest under study. Thus, all of the formulations we propose trade off harvested timber volume against the weighted number of preserved species. Each formulation represents a different management policy. Casting the models in a static setting allows us to analyze the effect of several management policies through computational experience with different forest-stucture — species relationships.

We present models for the design of routes for transportation of loads that might become hazardous or obnoxious to the population living along these routes. We take into consideration the fact that the values of the properties that are close to the roads used for the transportation may decrease as a consequence of this activity. As opposed to the traditional approach, of minimizing the population along the routes, we propose to include a compensation cost as a direct cost of choosing the routes. This compensation could include, for instance, a reduction in property tax rates. Two formulations are presented, covering different patterns of effects on property values. As an example of application of the models, we provide some computational experience.

ABSTRACTDue to the inherent multiobjective nature of many network design and routing problems, there has been a tremendous increase in multiobjective network modeling in recent years. In this article we introduce one such model, the minimum‐covering/shortest‐path (MinCSP) problem, and formulate several variations of the problem. The MinCSP problem is a two‐objective path problem: minimization of the total population negatively impacted by the path and minimization of the total path length. A population is considered to be negatively impacted by the path if the path comes within some predetermined distance of the population. Consequently, the MinCSP problem extends the concept of coverage from facility location modeling to network design. Additionally, several existing solution methods for the problem are briefly discussed and potential applications presented.

Most prior decision models for nature reserve-site selection have considered just two options for candidate sites: protected or not protected. In many reserve planning contexts this is an artificial and unrealistic limitation, as multiple categories of protection may be possible and desirable, especially if certain conservation elements such as rare species require special protection or management. In this paper we consider the implications of different levels of protection for species conservation and for the selection of reserve sites. New integer programming models are formulated for this problem of optimal site selection, and are presented in the context of a five-step procedure for identifying tradeoffs in the number of sites selected for each of multiple categories of protection. Results of a case study using data from Oregon are presented and compared to results from a previous study by Csuti et al.