Planning for forestation sustainability: Balancing environmental and socio-economic gain through species selection, harvest rotation and planting schedule decisions

• Main Author: Rollan, Catherine Denise L.
• Format: text
• Language: English
• Published: Animo Repository 2014
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/4704
• Institution: De La Salle University

The consideration of multiple dimensions is important especially in decisions where trade-offs exist. Such is the scenario in forestation where the pursuits in environmental gains and the maximization of socio-economic objectives, more often than not, involve decisions that lead to opportunities lost for the other. As few attempts have been found in practice and in literature, this study provides a way in which both socio-economic, in the form of income, and environmental, through carbon sequestration, interests are considered simultaneously. The system in consideration is a forestation project implemented by the government as the project proponent on a plot of land that does not have an existing forest. The land to be forested can serve multiple uses for protection, for carbon trading allocation, or for timber and fruit-harvesting. Income from timber and fruit harvesting as well as carbon trading goes to the community near the area that is assigned to implement the plans set by the government and take care of the forest. Environmental conditions in the area affect the biomass, volume and yield growths of each species. A non-linear mathematical model was developed with two competing objectives being maximized income and carbon sequestration. The objective of the model is to come up with a forestation plan detailing the number of trees of a particular species to plant, the schedule of their cutting and the schedule of their planting. The mathematical model allows for species switching such that when a forest stand is cut, the model considers the possibility of planting different species in place of it. The mathematical models output allows policy specifications made by the user such as area constraints for protection trees. It also considers the effect activities have on future conditions such as in tree cutting and soil moisture. The model is constrained by project parameters, environmental conditions and policy settings. Multi-objective optimization, through the use of the Epsilon-constraint method, was used in order to gain a set of pareto optimal solutions which provides the decision-maker, the government, with a set of plans and projected outcomes given tree species choices, environmental parameters, and project requirements. The provision of a set of pareto optimal solutions provides the project proponent a clearer perspective on the magnitude of the trade-offs such that decisions in favor of one objective can be made without bringing great detriment to the other objective. The studys results illustrate the effects of carbon trading, protected area requirement, and planning horizon on projected outcomes and decisions. Overall, carbon trading and protected area policies, while serving other purposes such as the fulfillment of targets like the Kyoto Protocol and the propagation of biodiversity, reduce both income and carbon sequestration outputs. On the other hand, the planning horizon in consideration affects the decisions of the plan. A shorter planning horizon favors trees that grow fast at the start. A planning horizon that is longer than the optimal cutting length of trees affects the timing of cutting where, instead of cutting trees based on optimal cycles, it distributes the cutting quantity in order to minimize the soil moisture losses incurred by timber harvests. Timing cutting activities this way ensures that the loss of soil moisture is not significant enough to hinder the optimal growth of trees that are not yet for cutting.