tailieunhanh - Báo cáo lâm nghiệp: "Evaluation through a simulation model of nutrient exports in fast-growing southern European pine stands in relation to thinning intensity and harvesting operations"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Evaluation through a simulation model of nutrient exports in fast-growing southern European pine stands in relation to thinning intensity and harvesting operations. | Ann. For. Sci. 64 2007 375-384 INRA EDP Sciences 2007 DOI forest 2007014 Available online at Original article Evaluation through a simulation model of nutrient exports in fast-growing southern European pine stands in relation to thinning intensity and harvesting operations Roque Rodríguez S0ALLEiR0a b Miguel Balboa MuRiASa Juan Gabriel Alvarez G0NZALEZa Agustin Merino GARCÍAa a Unidade de Xestión Forestal Sostible Universidad de Santiago de Compostela Escuela Politécnica Superior Campus Universitario 27002 Lugo Spain b Current address University of Wales School of Agricultural and Forest Sciences Bangor UK Received 19 June 2006 accepted 25 October 2006 Abstract - The effects on nutrient exports of a range of thinning regimes for maritime pine and radiata pine plantations in northern Spain were simulated in this study. Growth models tree biomass equations and nutrient concentration in tree fractions were used simultaneously to calculate the amounts of N P K Ca and Mg removed and left in the logging residues for five thinning intensities five site indexes and four harvesting scenarios for each species considering the whole rotation. A more intense thinning regime decreases the total amount of nutrients exported and increases the proportion of nutrients returned to the soil before the clearfell being a more progressive system of extracting nutrients from the ecosystem. A substantial amount of nutrients are located in the crown fractions and the bark making desirable the harvesting of debarked logs. The results allow the calculation of fertilization needs to avoid the depletion of soil nutrient capital in a variety of silvicultural situations. thinning nutrition growth model Pinus radiata Pinus pinaster Résumé - Evaluation grâce à un modèle de simulation des exportations de nutriments dans des peuplements européens de pins à croissance rapide en relation avec l intensité d éclaircie et les opérations de récolte. Les effets d une série de .