Physiological and anatomical leaf acclimation of understory trees subjected to a through-fall precipitation exclusion in a temperate rain forest in southern South America.

Water is an essential element in ecosystems, shaping their functionality, composition, and structure. Changes in water availability can impact ecosystem features, including biochemical cycles like carbon and nitrogen. Forests, composed of trees, heavily rely on water, absorbing it from the soil, storing it within their biomass, and releasing it through leaf stomata.

Canopies also intercept rainfall and fog, distributing water among the diverse biological life in these ecosystems. The trees' ability to acclimate to changing climates allows them to maintain ecosystem characteristics. In this study, researchers used a precipitation exclusion experiment to examine the acclimation of shade-tolerant understory trees, which will be crucial for the future cold temperate rainforest.

They evaluated various anatomical and physiological leaf traits involved in the use of water by these species. The researchers expected that species would adapt more conservative water-use strategies in response to changes, but found that understory tree species in this temperate ecosystem did not become more conservative in water use.

Instead, most of the studied species exhibited traits that indicated they were water spenders, rather than conservers, in the precipitation exclusion treatment. The researchers attribute these changes to reduced root metabolism due to flooded soils in the Chiloe forest inhabited by these trees.