Recurso. Modelo de crecimiento de árbol individual para plantaciones de pino radiata en el noroeste de España

Individual-tree basal area and height increment models were developed with data from 130 permanent plots of Pinus radiata D. Don located in Galicia (northwestern Spain). Mixed-models techniques were used for model fitting. Covariates acting at tree and stand level were included as fixed effects. Estimated values of stand variables obtained from aggregation of individual-tree predictions were used in model evaluation. The developed models accounted for 54% of the variability in basal area increment and 36% of the variability in height increment, with mean errors of 16 cm2 and 0.36 m, respectively. These models, along with an existing individual-tree mortality model, constitute a whole individual-tree growth model that can be used to simulate forest management alternatives, helping in forest managers’ decision making.En este estudio se han desarrollado modelos de incremento en sección normal y altura de árbol individual, utilizando datos de 130 parcelas de Pinus radiata D. Don localizadas en Galicia. La técnica de modelos mixtos se utilizó en el ajuste de los modelos. Se incluyeron covariables que actúan a nivel de árbol y a nivel de rodal como efectos fijos en los modelos. En la evaluación de los modelos se utilizaron estimaciones de variables de rodal obtenidas por agregación de las predicciones de árbol individual. Los modelos desarrollados explicaron el 54% de la variabilidad en el incremento en sección normal y el 36% de la variabilidad en el incremento en altura, con errores medios de 16 cm2 y 0.36 m, respectivamente. Estos modelos, junto al modelo de mortalidad de árbol individual existente, forman un modelo de crecimiento de árbol individual que puede utilizarse para simular alternativas de gestión forestal, ayudando a la toma de decisiones de los gestores forestales

Height-diameter models for maritime pine in Portugal: a comparison of basic, generalized and mixed-effects models

Tree height is a key variable in forest monitoring studies and for forest management. However, tree height measurement is time consuming, and the recommended procedure is to use estimates from height-diameter models. Here, we compare height-diameter model forms and approaches for predicting tree height (h) as a function of tree diameter at breast height (d) and additional stand level covariates. Four model forms were evaluated: (i) basic models (which only used d as predictor variable); (ii) generalized models (which used d and stand-level predictor variables); (iii) a mixed-effects model based on the best basic model; and (iv) a mixed-effects model based on the best generalized model. Several alternatives aimed at minimizing height measurement effort were tested in terms of accuracy and applicability. From a practical point of view, the selected generalized model is recommended for estimating the height of maritime pine in Portugal. The results also show that a calibrated basic mixed model provides more accurate results than a basic model locally fitted when the number of h-d observations is limited.S

Modelos de crecimiento y producción en España: historia, ejemplos contemporáneos y perspectivas

En el presente trabajo se presenta una revisión sobre los modelos forestales desarrollados en España durante los últimos años, tanto para la producción maderable como no maderable y, para la dinámica de los bosques (regeneración, mortalidad). Se presentan modelos tanto de rodal completo como de clases diamétricas y de árbol individual. Los modelos desarrollados hasta la fecha se han desarrollado a partir de datos procedentes de parcelas permanentes, ensayos y el Inventario Forestal Nacional. En el trabajo se muestran los diferentes submodelos desarrollados hasta la fecha, así como las plataformas informáticas que permiten utilizar dichos modelos. Se incluyen las principales perspectivas de desarrollo de la modelización forestal en España.In this paper we present a review of forest models developed in Spain in recent years for both timber and non timber production and forest dynamics (regeneration, mortality). Models developed are whole stand, size (diameter) class and individual-tree. The models developed to date have been developed using data from permanent plots, experimental sites and the National Forest Inventory. In this paper we show the different sub-models developed so far and the friendly use software. Main perspectives of forest modeling in Spain are presented.The models described in this paper were funded by different regional, national and European projects, and some of them were elaborated by the authors. This work was funded by the Spanish Government by the SELVIRED network (code AGL2008-03740) and the strategic project «Restauración y Gestión Forestal» (code PSE-310000-2009-4)

Growth and yield models in Spain Historical overview, contemporary examples and perspectives

In this paper we present a review of forest models developed in Spain in recent years for both timber and non timber production and forest dynamics (regeneration, mortality). Models developed are whole stand, size (diameter) class and individual-tree. The models developed to date have been developed using data from permanent plots, experimental sites and the National Forest Inventory. In this paper we show the different sub-models developed so far and the friendly use software. Main perspectives of forest modeling in Spain are presented

Development of ecoregion-based merchantable volume systems for Pinus brutia Ten.;Pinus nigra Arnold. in southern Turkey

Estimating individual tree volume is one of the essential building blocks in forest growth and yield models. Ecologically based taper equations provide accurate volume predictions and allow classification by merchantable sizes, assisting in sustainable forest management. In the present study, ecoregion-based compatible volume systems for brutian pine and black pine in the three ecoregions of southern Turkey were developed. Several well-known taper functions were evaluated. A second-order continuous-time autoregressive error structure was used to correct the inherent autocorrelation in the hierarchical data, allowing the model to be applied to irregularly spaced and unbalanced data. The compatible segmented model of Fang et al. (For Sci 461–12, 2000) best described the experimental data. It is therefore recommended for estimating diameter at a specific height, height to a specific diameter, merchantable volume, and total volume for the three ecoregions and two species analyzed. The nonlinear extra sum of squares method indicated differences in ecoregion and tree-specific taper functions. A different taper function should therefore be used for each pine species and ecoregion in southern Turkey. Using ecoregion-specific taper equations allows making more robust estimations and, therefore, will enhance the accuracy of diameter at different heights and volume predictions. © 2015, Northeast Forestry University and Springer-Verlag Berlin Heidelberg