tailieunhanh - Báo cáo lâm nghiệp:"High-grading effects on Scots pine volume and basal area in pure stands in northern Spain"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài:"High-grading effects on Scots pine volume and basal area in pure stands in northern Spain" | 11 Ann. For. Sci. 60 2003 11-18 INRA EDP Sciences 2003 DOI forest 2002069 Original article High-grading effects on Scots pine volume and basal area in pure stands in northern Spain Felipe Bravoa and Gregorio Monterob a Dept. de Producción Vegetal y Silvopascicultura University of Valladolid Campus at Palencia Avda. de Madrid 44 34004 Palencia Spain b CIFOR-INIA PO Box 8011 28080 Madrid Spain Received 24 January 2002 accepted 25 March 2002 Abstract - A yield model for formerly high-graded Scots pine stands in a transitional climatic area in northern Spain has been developed. High grading practices were used broadly during the last decades. In the past years the silvicultural system has switched to a conventional even-aged system. A modeling approach is used to understand the effects of high-grading on basal area and dominant height. The equations are calibrated to be used in non high-graded stands and in previously high-graded stands when the silvicultural practices are switched. Dominant height and linear models were used to calibrate the original multiplicative model. With these models the effect of high-grading practices upon forest yield was studied. Standing volume decreased due to high-grading over 26 as the rotation age increased in a medium productivity class. The total volume reduction at rotation age was 18 . Pinus sylvestris high-grading yield Scots pine Spain Résumé - Effets du système de coupe à la dimension sur le volume et la surface terrière de peuplements de Pin sylvestre au nord de l Espagne. On a mis au point un modèle de croissance des peuplements de Pin sylvestre soumis auparavant à ce système dans une region climatique de transition située au nord de l Espagne. Ce type de sylviculture consistant à récolter systématiquement les arbres de gros diamètre a été courant au cours des dernières décennies. Depuis quelques années on abandonne cette methode pour adopter le traitement en futaie régulière. On a fait appel à l approche modélisation .