Resumo

TORRES-ROJO, Juan M.. Exploring volume growth-density of mixed multiaged stands in northern Mexico. Agrociencia [online]. 2014, vol.48, n.4, pp.447-461. ISSN 2521-9766.

The volume growth-density relationship has been studied in even-aged forest stands. Few research reports have deepened in the analysis of such a relationship in mixed multiaged stands to include a wider variety of state variables and more than two species. The objective of this research was to analyze the combined effect of state variables, such as density, site quality, and species composition over volume growth of mixed multiaged forest stands. The analysis is based on a nested segmented model where each segment follows the logistic law of growth. Parameter estimates in each segment are computed by fitting long term data to a simultaneous equations system. Data were obtained from plots established during 1966 and 1968 in the Cielito Azul Experiment Area, state of Durango, Mexico. Results show that volume growth is more accurately predicted throughout the segmented logistic model where each parameter is endogenously predicted from stand state variables. The model improves the fit of the volume growth- density relationship and reveals that the Langsaeter's curve can be extended to multiple species and stand structures. In addition, it suggests that the range of densities with similar growth identified in Langsaeter's curve is highly dependent on species composition and site quality.

Palavras-chave : Volume growth prediction; Langsaeter's curve; logistic model; species mixture; multiaged stands.