TAILIEUCHUNG - Báo cáo khoa học: "Performance and morphological response of the hybrid poplar DN-74 (Populus deltoides x nigra) under different spacings on a 4-year rotation"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Performance and morphological response of the hybrid poplar DN-74 (Populus deltoides x nigra) under different spacings on a 4-year rotation. | 275 Ann. For. Sci. 56 1999 275-287 Inra Elsevier Paris Original article Performance and morphological response of the hybrid poplar DN-74 Populus deltoìdes X nigra under different spacings on a 4-year rotation Guy R. Larocque Natural Resources Canada Canadian Forest Service Laurentian Forestry Centre 1055 du . . Box 3800 Sainte-Foy Quebec G1V 4C7 Canada Received 8 April 1998 accepted 15 December 1998 Abstract - The effect of competition on the performance and morphological response of the hybrid poplar DN-74 Populus deltoides X nigra was examined by varying stand density from 4 444 stems ha 1 to 40 000 stems ha . The root collar diameter growth of individual trees was inversely related to the intensity of competition as there was nearly a two-fold decrease in root collar diameter from the largest to the closest density after only four growing seasons. Crown width crown ratio leaf biomass and leaf area decreased significantly with an increase in density. However crown shape ratio leaf area projection and leaf area ratio did not vary significantly with stand density and specific leaf area decreased with the degree of crown closure and crown depth which indicated that this hybrid shows a high degree of plasticity in response to competition. Nutrient contents of foliage and stems did not vary much with the intensity of competition. Inra Elsevier Paris. relative growth rate leaf area specific leaf area competition short rotation forestry Resume - Performance et réponse morphologique du peuplier hybride DN-74 Populus deltoides X nigra sous differents espacements pour une rotation de quatre ans. L effet de la competition sur la performance et la réponse morphologique du peuplier hybride DN-74 Populus deltoides X nigra a été examine en faisant varier la densité de 4 444 tiges ha 1 à 40 000 tiges ha .La crois-sance en diamètre au niveau du collet était inversement reliée à Pintensité de la competition le diamètre au niveau du collet a dimi-nué de moitié de la plus

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