Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Effects of relative irradiance on the leaf structure of Fagus sylvatica L. seedlings planted in the understory of a Pinus sylvestris L. stand after thinning. | Ann. For. Sci. 58 2001 673-680 INRA EDP Sciences 2001 673 Original article Effects of relative irradiance on the leaf structure of Fagus sylvatica L. seedlings planted in the understory of a Pinus sylvestris L. stand after thinning Ismael Aranda Luis Felipe Bergasa Luis Gil and José Alberto Pardos Escuela Técnica Superior de Ingenieros de Montes Universidad Politécnica de Madrid Ciudad Universitaria s n 28040 Madrid Spain Received 27 April 2000 accepted 7 February 2001 Abstract - Beech seedlings were established in the understory of a Pinus sylvestris plantation close to one of the southernmost populations of beech in Europe the beech-oak forest of Montejo de la Sierra. Four years later the overstory was partially reduced by removing pine trees. Solar radiation in the understory was evaluated by hemispherical canopy photographic technique and the effects of relative irradiance increment on the leaf anatomy of beech seedlings were analyzed during the two years after opening the stand. The increase in specific leaf mass SLM in seedlings during both years runs in parallel with the increase in relative irradiance estimated by the global light factor GLF which expresses the proportion of global radiation relative to that in the open. There were significant relationships between the light index as a surrogate of light environment and the morphological and anatomical characteristics of the leaves. In the first year SLM increase was more related to total blade thickness. In the second year thickness of palisade parenchyma PP appears more relevant than that of spongy tissue SP as indicated by the absence of significance in the relationship between SP and SLM. Moreover sto-matal density was also higher according to increasing relative irradiance. The shift response of beech seedlings to the overstory opening makes evident their capability of acclimatization to light increase through changes in leaf anatomy. Fagus sylvatica morphology leaf hemispherical photography .
