Towards Sustainable Timber Harvesting of Homogeneous Stands: Dynamic Programming Techniques in Synergy with Forest Growth Simulation

Abstract: As the threat of the climate change becomes more real, one of the main fronts to attack this problem is the preservation and increase of landmass of forests in the world to capture carbon dioxide from the atmosphere. Mexico, being one of the countries with the largest forest reservoirs has a great responsibility to accomplish this task. However, as the timber industry is an important part of the economical activities of the country, it is important to find a compromise that allows to extract the maximum amount of timber, without compromising the capacity of the forest to regenerate naturally. In the past, there have been approaches that use exact methods that solve this problem, but considering the stand as a whole, other approaches, use software simulation software, but use approximate solution methods to optimize the harvesting. In this work, we propose an approach to help to achieve this goal: a dynamic programming method that optimizes the volume of wood harvested at the end of a planning horizon, divided on thinning periods of equal length. In order to make the results closer to reality, we included a module of the ForestSimulator BWIN Pro to simulate the growth of the forest taking into accout different aspects such as competition, mortality and reincorporation of individual trees. With these tools, we were able to explore and assess different alternatives for the parameters of thinning percentage on each period, duration of each period and the planning horizon, the criteria of selection of the trees to be harvested, among others. The results showed us that the proposed method is useful not only as a tool to optimize the harvesting of the timber of a homogeneous stand, but to explore different alternatives to the established practices, that continue to change constantly.