Abstract

CHAVEZ-FLORES, Gustavo Alfredo et al. Spatial structure of the mixed and uneven-aged forests in the state of Durango. Rev. mex. de cienc. forestales [online]. 2020, vol.11, n.59, pp.141-162.  Epub July 15, 2020. ISSN 2007-1132.  https://doi.org/10.29298/rmcf.v11i59.614.

The purpose of this work was to describe the spatial structure and research the interactions or correlations among certain tree characteristics in the mixed and uneven-aged forests in the state of Durango. Data of individual tree location and other tree attributes of 446 permanent forest research plots were used. The spatial tree distribution and the interactions among groups of species were determined with the use of the second-order statistic known as Ripley's K function in its univariate L(r) and bivariate L 12 (r) normalized forms. The dimensional association between the sizes of the tree diameters was evaluated with the use of the mark correlation function Kmm(r). The results provided by these statistical tools allow to determine that the spatial structure of the evaluated forests has a complex nature and depends on the scale at which it is analyzed. At distances under 2 m, the random spatial distribution of the trees dominates, while at distances over 2 m the clustering of trees is prevalent. On the other hand in most of the studied sites no significant interactions or mixtures in the spatial distribution of trees of pine and oak were observed, indicating that regeneration and selective silviculture follow a random pattern. The analysis of the spatial interaction between the tree diameter sizes keeps an independent spatial distribution pattern, in which trees with different diameters are mixed randomly within the studied sites.

Keywords : Spatial distribution; mark correlation function; Ripley's K function; point pattern; Sierra Madre Occidental; permanent forest and soil research sites.