5. Conclusions
The data presented in this study related to plantation productivity, aboveground biomass and nutrient concentration and C content by tree compartment, aboveground biomass equations by tree compartment, soil nutrient reserves stability indices, plus already published information (e.a [13] and [1]), can be used as a reference for: a) selection of tree species vs site characteristics, b) estimation of nutrient export by stem þ bark harvesting, c) planning for a second rotation, c) maintenance of site productivity and d) generate better carbon sequestration estimations.
In light of the results of this study, the total lack of interest in Costa Rica to plant Pinus caribae and other Pinus species deserves future consideration for three main reasons: a) these species competes very well on degraded or unfertile soils with T. grandis and G. arborea with the advantage of having higher carbon fixing capacity and better soil nutrient stability indices, b) the silviculture and wood technological package for industrial use of this species is well known, c) the timber from this species is widely used and has a guaranteed market. Surprisingly this species has been neglected in commercial and small farmers’ reforestations projects because of its ecological reputation. Further discussion on this issue must take place between ecologists and foresters to recognize that this species is a useful alternative for small landowners who are willing to plant small plots, live fences or wind breaks on degraded lands. These farmers will plant trees with the fair expectation of an economical return and with minimum management requirements to improve their livelihoods.We agree that P. species is not one of the best choices for biological conservation, but is an excellent choice for other ecological services such as soil and water conservation, restoration of degraded lands and carbon sequestrations, while undoughtily supporting rural economy and land use diversification.