tailieunhanh - Báo cáo lâm nghiệp:"Wind-firmness in Pinus pinaster Aït. stands in Southwest France: influence of stand density, fertilisation and breeding in two experimental stands damaged during the 1999 storm"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài:"Wind-firmness in Pinus pinaster Aït. stands in Southwest France: influence of stand density, fertilisation and breeding in two experimental stands damaged during the 1999 storm" | Ann. For. Sci. 60 2003 209-226 INRA EDP Sciences 2003 DOI forest 2003013 209 Original article Wind-firmness in Pinus pinaster Alt. stands in Southwest France influence of stand density fertilisation and breeding in two experimental stands damaged during the 1999 storm Véronique Cucchi and Didier Bert Laboratoire Croissance et Production Unité de Recherches Forestieres de Pierroton Institut National de la Recherche Agronomique - Bordeaux 69 Route d Arcachon 33612 Cestas Cedex France Received 10 October 2001 accepted 12 August 2002 Abstract - Maritime pine Pinus pinaster stands in the Aquitaine region are of great economic importance but subject to Atlantic storms. In the Bordeaux region two experimental sites located near each other aged 20 and 51 years made it possible to study the effects of different types of silviculture on wind-firmness during the 1999 storm. Stand density has a major influence on tree growth. When density increases height increases and circumference decreases appreciably. In the dense stands windthrown trees were less abundant and there were more leaning pines. With respect to other silvicultural factors in stands planted at typical densities i genetic breeding did not increase damage intensity at the 20-year-old experimental site and phosphorus fertilisation decreased the windthrow at the 51-year-old experimental site ii compared to the undamaged trees the circumference of windthrown trees was cm smaller the relative crown length was 10 shorter and the stem taper coefficient was higher. This research has shown that wind-firmness is better in stands where the height circumference and crown length are homogeneous. A more closed canopy seems to improve wind resistance by increasing the damping effect of swaying as a result of the crowns being in contact with each other and provides a more favourable ratio between the aerial parts and the roots. windthrow silviculture Pinus pinaster stability storm Résumé - Résistance au vent de .