Matjaž Čater
Shoot morphology and leaf gas exchange of Fagus sylvatica as a function of light in Slovenian natural beech forests
Dendrobiology 2010, vol. 64: 03-11
Abstract: Five plots with young beech trees of the same age (13-15 years) were established to study the
threshold, where plagiotropic growth becomes evident as the consequence of the reduced light intensity.
Trees were equally distributed along the light gradient and were divided according to light conditions (Indirect Site Factor, ISF) into three groups of stand conditions: close canopy stand(ISF25). Morphological and physiological responses of young beech were studied between managed and old growth forest and between different forest complexes (Pohorje and Kočevje region) on natural beech sites. Criteria for the plagiotrophic growth was the relation between tree length and tree height (l/h) under various light conditions. Under controlled conditions (temperature, flow and CO2 concentration, RH, light intensity) light saturation curves of leaf net photosynthesis were measured on same trees to compare both responses between different light categories and different plots within comparable light conditions. Our study confirmed different thresholds for morphologic response between two forest complexes as well as between old growth and managed forest. Results were in accordance with physiological responses: the value of limiting light for a plagiotropic response was lower in Kočevje (17% ISF) than on Pohorje (25% ISF).
Additional key words: light, plagiotropic growth response, light saturation curves, managed and old growth beech forest.