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Báo cáo khoa học: "Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica)"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica). | Ann. For. Sci. 59 2002 801-812 INRA EDP Sciences 2002 DOI 10.1051 forest 2002078 801 Original article Spatial and seasonal variations in stem respiration of beech trees Fagus sylvatica Éric Ceschiaa Claire Damesina Stéphanie Lebaubeb Jean-Yves Pontaillera and Éric Dufrênea a Université Paris XI Laboratoire d écophysiologie végétale Bât. 362 91405 Orsay France b UMR INRA UHP Écologie et Écophysiologie forestières 54280 Champenoux France Received 18 April 2002 accepted 19 June 2002 Abstract - Stem respiration of adult beech Fagus sylvatica L. trees was measured in the field in eastern France at several levels in the crown and along the stem. Strong variations in respiration rates throughout the season and within the trees were mainly caused by gradients in stem temperature growth rates and distribution of living cells. The higher respiration rates were measured in the upper crown. During the non-growing season maintenance respiration ranged between 7.2 and 528 lmol m-3 s-1 at breast height and in the upper crown respectively. Q10 increased along the stem from 1.3 at breast height to 2.0 in the upper crown. There was a linear relationship between N and the percentage of living cells in the wood but respiration increased strongly with N . Growth respiration accounted for 45-76 of annual stem respiration and the growth respiration coefficient was close to 0.2 g C respired g-1 C fixed. beech stem and branch respiration living cell nitrogen concentration Résumé - Variations spatiales et saisonnières de la respiration ligneuse chez le Hêtre Fagus sylvatica . La respiration ligneuse a été me-surée de faẹon continue sur des Hêtres Fagus sylvatica L. adultes dans une forêt de l est de la France à trois niveaux dans la couronne de branches en 1997 et à deux voire trois niveaux le long du tronc en 1998. Les fortes variations du taux de respiration observées au cours de la saison et au sein de l arbre étaient essentiellement causées par des gradients de température de taux de .