Modeling individual-tree mortality in Pyrenean oak (Quercus pyrenaica Willd.) stands

Abstract

Keywords:individual-tree mortality model / logistic regression / mixed model / rebollo oak / Mediteranean oak Abstract • Tree mortality is an important process in forest ecosystem dynamics and is one of the least understood phenomena, because of the complex interactions between different environmental stresses, minimal understanding of whole-plant mortality processes, and a chronic shortage of data.• A multilevel logistic regression model was developed for predicting the probability of mortality in individual trees with the objective of improving long-term planning in Spanish pyrenean oak forests. The data came from one 10-year re-measurement of the permanent plot network belonging to the Spanish National Forest Inventory distributed throughout north-west Spain.• The probability of mortality decreased with increasing individual diameter at breast height and increasing ratio of the height of subject tree to the dominant height of the sample plot. The resulting mortality model was evaluated using an independent data set from a region close to the study area.• The regeneration of pyrenean oak generally takes place through stump and/or root sprouting; so stand dynamics differ from those of others species. The model developed is expected to improve the accuracy of stand forecasts in northwest Spain.

Regional-scale stand density management diagrams for Pyrenean oak (Quercus pyrenaica Willd.) stands in north-west Spain

“…As a result of this interest, a wide range of studies have been published in the last few decades. These studies have included the following aspects (amongst others): development of site index curves, in León (Torre 1994), La Rioja (Bengoa 2000), Castilla y León (Adame et al 2006) and Galicia (Díaz-Maroto et al 2010); fitting height-diameter models (Adame et al 2008); modeling mortality (Adame et al 2010); stand yield in terms of biomass (Allué & San Miguel 1991, Carvalho 2005; and estimation of carbon stocks in Pyrenean oak stands, both in soils (Díaz-Pines et al 2011) and in wood (Castaño-Santamaría & Bravo 2012). However, only one stand-level model has been developed to date and this refers to the province of Leon (Bravo et al 2011).…”

Climatic information improves statistical individual-tree mortality models for three key species of Sichuan Province, China

“…Since we did not know exactly the year when trees died between 2002 and 2007, the growth time for dead trees would be less than 5 years and, thus, the relBAIs (i, 2002, 2007) of trees were not used. Diameter at breast height was used in lieu of tree age (Adame et al 2010). The nonlinear or U-shaped curve effects can be captured with a hyperbolic D −1 or D and D 2 transformation of diameter, respectively (Monserud and Sterba 1999;Adame et al 2010).…”

“…Diameter at breast height was used in lieu of tree age (Adame et al 2010). The nonlinear or U-shaped curve effects can be captured with a hyperbolic D −1 or D and D 2 transformation of diameter, respectively (Monserud and Sterba 1999;Adame et al 2010). …”

“…The commonly used variables of individual scales include tree species, tree size (a proxy for tree age measured by diameter and height, and crown width), and tree growth, such as diameter increment, basal area increment, and relative basal area increment (Monserud and Sterba 1999;Wyckoff and Clark 2000;Adame et al 2010). Tree size, which is influenced greatly by multiple factors, could help in the search for the causes of tree death in modeling tree mortality, and was the most popular factor in previous studies (Monserud and Sterba 1999;Yang et al 2003;Crecente-Campo et al 2009).…”

“…Therefore, most tree-mortality models have focused on non-catastrophic mortality because of the highly variable and stochastic nature of the catastrophic events (Fridman and Ståhl 2001;Crecente-Campo et al 2009). Individual-tree-based mortality models not only show details of each tree for improving forest management but also provide information about the processes and factors related to individual tree death (Monserud and Sterba 1999;Wunder et al 2008;Adame et al 2010). Moreover, many ecosystem models have not explicitly considered tree mortality due to the lack of information on tree death and its relationships with climate factors (Wang et al 2012).…”