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Leaf area is an important ecophysiological and silvicultural variable for quantifying the potential production of trees, since it can represent growing space occupancy. At the stand level in mixed forests, productivity is conditioned on how growing space is distributed among different components structure, such as species and strata. In complex structures, traditional forest variables (i.e., basal area) do not allow a good representation of the occupied growing space, whereas leaf area appears as a better indicator. Andean cypress and coihue beech are species of the Andean-Patagonian forests that grow in either pure or mixed stands, presenting high productive potential. The aim of this study was to develop, for each species, leaf area prediction functions through allometric relations and to evaluate the relation between leaf area, volume increment and growing space occupancy. For this purpose, we carried out destructive sampling of individuals of both species in mixed Andean cypress-coihue forests. Results for these species show that leaf area can be reliably estimated by using the models developed in this study. These models, based on sapwood area, tree diameter, and/or height measurements, explain at least 90 percent of variation in leaf area. The functions fitted are a fundamental tool to study the distribution of growth and to formulate management guidelines for mixed forests through the control of growing space occupancy using leaf area index. [ABSTRACT FROM AUTHOR]

Andean cypress and coihue beech are endemic species of the Patagonian Andean forests of Argentina. Both species grow in either pure or mixed stands. Some pure cypress stands are affected by a root disease called "mal del ciprés," reducing their possibilities of being managed for timber production. Coihue beech could be introduced in pure sick cypress stands to help recover their productive potential. However, knowledge is limited about how soil moisture and light may affect early establishment of seedlings of both species. In this study, we determined, under nursery conditions, how survival and growth of cypress and coihue beech seedlings are affected by the combined effects of different soil moisture and light conditions. Both species showed similar survival and growth responses and were susceptible to extreme drought. While similar survival percentages were shown between them, low light levels and higher adaptation to drought significantly delayed cypress seedling mortality compared with coihue beech. Low light and moisture levels negatively affect growth, while the highest growth was registered at intermediate and high levels of light and soil moisture. Although coihue beech seedlings grew faster than cypress, both have the potential for recovering cypress stands affected by "mal del ciprés". [ABSTRACT FROM AUTHOR]