Stand level volume increment in relation to leaf area index of Austrocedrus chilensis and Nothofagus dombeyi mixed forests of Patagonia, Argentina

The growing space occupied by trees in a forest stand -understood as the set of site resources used by trees-, can be reasonably represented by the leaf area index (LAI). Through different silvicultural management activities, stand structure can be manipulated to provide more growing space for the most efficient components that, related to the growing space they occupy, may improve the productivity of the stand. Austrocedrus chilensis and Nothofagus dombeyi, can grow in mixed forests presenting generally two height layers of high productive potential. However, it is necessary to know how these trees grow for designing target management structures to maximize stands productivity. The objective of this study was to determine, in mixed A. chilensis and N. dombeyi forests, the effect that the distribution of the leaf area, by species and height strata, has on the productivity of the stand. Results showed that the stand volume increment was more related to the distribution of the LAI by species than to the total LAI of the stand. Nothofagus dombeyi contributed more to the stand growth and showed twice the growing space efficiency than A. chilensis per unit of leaf area. In addition, growing space efficiency of the species decreased as the LAI of the stand increased. It appears that in these mixed forests, N. dombeyi is the main regulator of productivity.

Automated summary

The distribution of leaf area by species has a significant impact on stand productivity, with Nothofagus dombeyi being the main regulator of productivity in mixed forests. Manipulating stand structure through silvicultural management activities can improve stand productivity by providing more growing space for efficient components. The study found that stand volume increment was more related to species-specific distribution of leaf area than the total leaf area index of the stand.