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Articles by Rafael Calama

Category : Research article

article id 1226, category Research article
Santiago Pereira, Antonio Prieto, Rafael Calama, Luis Diaz-Balteiro. (2015). Optimal management in Pinus pinea L. stands combining silvicultural schedules for timber and cone production. Silva Fennica vol. 49 no. 3 article id 1226. https://doi.org/10.14214/sf.1226
Keywords: forest management; goal programming; non-timber forest product
Highlights: Three management scenarios are proposed to integrate timber and pine nuts; Different silvicultural regimes for each output are addressed jointly; Goal programming is used in order to solve forest management models; In the mixed scenario, the area allocated to pine nuts should be notably greater.
Abstract | Full text in HTML | Full text in PDF | Author Info

This work aimed to tackle a timber harvest scheduling problem by simultaneously integrating into the analysis two forestry products derived from the same species: the timber and the pine nut. For this purpose, three management scenarios were proposed: two in which each of the productions is maximised separately, and a third mixed where, in each management unit, the product to which the silvicultural effort should be devoted is decided. After defining a set of objectives, and optimising the rotation length, a multi-criteria model based on goal programming was considered since no feasible solutions have been obtained when employing linear programming. The results in our case study show how the feasible solutions reached can be more attractive for the manager. Specifically, the area to be devoted to timber and cone/pine-nut production was computed in a scenario where the optimal silviculture (oriented towards timber or pine nuts) in each stand was selected, and it was concluded that the area allocated to pine nuts should be notably greater. This situation is the opposite of the current management.

  • Pereira, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain E-mail: spereirasaez@gmail.com
  • Prieto, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain E-mail: antonio.prieto@upm.es
  • Calama, Dpto. Selvicultura y Gestión Forestal, INIA-CIFOR, Ctra. A Coruña km 7.5, 28040 Madrid, Spain E-mail: rcalama@inia.es
  • Diaz-Balteiro, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain E-mail: luis.diaz.balteiro@upm.es (email)
article id 394, category Research article
Rafael Calama, Gregorio Montero. (2005). Multilevel linear mixed model for tree diameter increment in stone pine (Pinus pinea): a calibrating approach. Silva Fennica vol. 39 no. 1 article id 394. https://doi.org/10.14214/sf.394
Keywords: mixed model; diameter increment; calibration; stone pine
Abstract | View details | Full text in PDF | Author Info
Diameter increment for stone pine (Pinus pinea L.) is described using a multilevel linear mixed model, where stochastic variability is broken down among period, plot, tree and within-tree components. Covariates acting at tree and stand level, as breast height diameter, density, dominant height or site index are included in the model as fixed effects in order to explain residual random variability. The effect of competition on diameter increment is expressed by including distance independent competition indices. The entrance of regional effects within the model is tested to determine whether a single model is sufficient to explain stone pine diameter increment in Spain, or if, on the contrary, regional models are needed. Diameter increment model can be calibrated by predicting random components using data from past growth measurements taken in a complementary sample of trees. Calibration is carried out by using the best linear unbiased predictor (BLUP) theory. Both the fixed effects model and the calibrated model mean a substantial improvement when compared with the classical approach, widely used in forest management, of assuming constancy in diameter increment for a short projection period.
  • Calama, CIFOR-INIA, Grupo Selvicultura Mediterranea, Apdo. 8111, 28080 Madrid, Spain E-mail: rcalama@inia.es (email)
  • Montero, CIFOR-INIA, Grupo Selvicultura Mediterranea, Apdo. 8111, 28080 Madrid, Spain E-mail: gm@nn.es

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