Tree mortality in mature temperate forests of central Mexico: a spatial approach

Abstract

Tree mortality is an important process of forest stand dynamics and knowledge of it is fundamental to implement adequate management strategies. Subject to several factors, tree mortality can induce different spatial patterns on the remaining live and dead trees. While spatially clustered tree mortality in young forests is often driven by competition, in old-growth forests, spatially clustered tree mortality is often caused by disturbance agents. This study is focused on a spatiotemporal analysis of tree mortality in a mature temperate forest located in central Mexico dominated by Pinus montezumae and Alnus firmifolia. We used tree locations from a permanent plot (300 × 300 m) measured over a 20-year period. The results, from applying point pattern analysis, showed that the spatial pattern of all dead trees was clustered at short to medium distances, but showed no clear deviation from complete spatial randomness at longer distances. Similar results were found for P. montezumae and A. firmifolia. Using the bivariate mark-connection function (alive and dead trees), no tree mortality caused by competition was discernable, only A. firmifolia showed a tendency toward competition-introduced mortality around 15 m. Regarding forest structure, alive trees retained a clustered distribution and size heterogeneity at different distances during the measurement period. Thus, there was evidence that the resulting spatial pattern of tree mortality could be explained by disturbance agents such as droughts rather than tree competition. Therefore, the results of this study can contribute to implement management strategies based on the principles of continuous cover forestry and provide novel information regarding tree mortality in Mexican montane forests.

Distribución espacial de Pinus y Quercus en un gradiente altitudinal de bosque templado en Guadalupe y Calvo, Chihuahua

“…Revista Mexicana de Ciencias Forestales Vol. 15 (81) Los patrones de distribución espacial se determinaron a partir de parámetros estructurales basados en las relaciones entre un árbol referencia (i) y sus cuatro vecinos más cercanos, lo que expresa apropiadamente las características estructurales espaciales de las comunidades vegetales y permite diseñar prácticas de manejo más adecuadas a las condiciones específicas de los bosques (Hui y Gadow, 2002;Pastorella y Paletto, 2013;Rubio-Camacho et al, 2023).…”

A simulation study comparing common methods for analyzing species–habitat associations of plants

“…Worldwide, individuals in tree and shrub populations tend to be spatially clustered. This is true in tropical forests (Condit et al., 2000; Jara‐Guerrero et al., 2015), temperate forests (Getzin et al., 2006; Rubio‐Camacho et al., 2023), boreal forests (Gray & He, 2009; Das Gupta & Pinno, 2018), secondary forests (Jia et al., 2016), savanna shrublands (Hesselbarth et al., 2018) or natural grasslands (Alvarez et al., 2011; Browning et al., 2014). This clustering is caused by biotic processes, abiotic processes, or a combination of both (Cottenie, 2005; Legendre et al., 2009).…”