Pith Eccentricity, Basal Area Increments and Disturbances Inferred from Tree-Ring Growth

Abstract

Forest management constantly seeks tools that can optimize the production of goods and services. As natural archives, tree rings have proven to be effective in terms of refining the dynamics of growth on a temporal basis. This study evaluates the application of these tree rings in estimating the effect of pith eccentricity on forest growth, modeling the increase in basal area (BAI) and identifying disturbances in five coexisting species in northern Mexico. A Wilcoxon rank sum test showed significant differences, with higher radial growth in the north direction compared to the other directions. A mixed model analysis revealed two patterns of BAI growth, fast and slow growing. The former includes P. arizonica, P. engelmannii and P. leiophylla, whereas the latter comprises P. durangensis and P. lumholtzii. The fast-growing group shows a higher increment during the sapling stage. However, during subsequent stages, it presents growth rates similar to those of the slow-growing group. Finally, the percentage growth change (PGC) filter approach identified species disturbances with differential species responses, which temporarily cause uneven-aged forest. We conclude that tree rings can provide valuable information for forest management, and their temporal amplitude can be supported with information from permanent plots.