Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Growth and fructification of a Norway spruce (Picea abies L. Karst) forest ecosystem under changed nutrient and water input. | Ann. For. Sci. 59 2002 359-368 INRA EDP Sciences 2002 DOI forest 2002012 359 Original article Growth and fructification of a Norway spruce Picea abies L. Karst forest ecosystem under changed nutrient and water input Achim Dohrenbuscha Stefan Jaehnea Michael Bredemeierb and Norbert Lamersdorfc a Institute of Silviculture Gottingen University Busgenweg 1 37077 Gottingen Germany b Forest Ecosystems Research Center Busgenweg 1 37077 Gottingen Germany c Institute of Soil Science and Forest Nutrition Busgenweg 2 37077 Gottingen Germany Received 25 July 2001 accepted 25 January 2002 Abstract - In the mountainous region of a low mountain range Solling mountains an ecosystem manipulation experiment with roof constructions underneath the canopy of a 60-year old Norway spruce stand is run since 1991. The responses to artificially prepared preindustrial through fall and to extended summer droughts with intensive rewetting are investigated in two parallel roof experiments and evaluated against a roof control and an ambient control plot. After long terms of drought distinct reactions of the trees were visible in growth. The reactions of height-increment were more distinct than the effects on diameter-increment. Furthermore the trees of the dominating social classes Kraft I and II reacted more on low water-supply than the dominated trees. So it is probable that a long lasting stress by drought effects changes the stand structure too the vertical structure of a stand would get more homogeneous and the diversity in the stand structure would decrease. Reduced input of sulphur and nitrogen did not show any distinct growth reactions within the 9-year observation period. roof-project nitrogen drought growth fructification Résumé - Croissance et fructification d un écosystème forestier d épicéa commun soumis à un apport variable d eau et de nutriments. Dans la partie haute d une region montagneuse de moyenne altitude Solling on procède depuis 1991 à une experience de .
