Maritime pine is the second most representative species in terms of area in Portugal, with 40% of the stands being uneven-aged (AFN 2010). PBIRROL model was publish in 2013 following the work of Alegria (2004). It is an individual tree model that includes a distance independent- and a dependent version of the growth module. Beside the survival model and the diameter growth model, PBIRROL also integrates an ingrowth module; a thinning module which applies thinning according to the criteria of the local forest managers; and a volume module, that integrates s system of equations for estimating total volume (over and under bark) and volumes by assortment (Alegria and Tomé, 2013).

The version of PBIRROL implemented in StandsSIM allows the user to set the thinning based on user-defined probabilities according to tree size as well as based on several other criteria, such as the Wilson factor, the residual basal area and the percent basal area.


AFN: Autoridade Florestal Nacional, 2010. 5º Inventário Florestal Nacional. Apresentação do relatório Final. AFN, MADRP, Lisboa.

Alegria C, 2004. Estudo da dinâmica do crescimento e produção dos povoamentos naturais de pinheiro bravo na região de Castelo Branco. PhD thesis, Universidade Técnica de Lisboa, Instituto Superior de Agronomia, Lisboa, Portugal.

Alegria C, Tomé M, 2013. A tree distance-dependent growth and yield model for naturally regenerated pure uneven-aged maritime pine stands in central inland of Portugal. Annals of Forest Science 70(3): 261-276. DOI: 10.1007/s13595-012-0262-8.

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