TAILIEUCHUNG - Báo cáo lâm nghiệp: "The allometric model in the stand density management of Pinus pinaster Ait. in Portugal"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: The allometric model in the stand density management of Pinus pinaster Ait. in Portugal. | Ann. For. Sci. 61 2004 807-814 807 INRA EDP Sciences 2005 DOI forest 2004077 Original article The allometric model in the stand density management of Pinus pinaster Ait. in Portugal Jaime F. Sales Luis Teresa F. Fonseca Departamento Florestal Universidade de Trás-os-Montes e Alto Douro 5000 Vila Real Portugal Received 16 July 2003 accepted 17 June 2004 Abstract - The allometric model is very suitable for practical applications as it gives an approximately correct expression of a number of relations such as plant density N and average plant size dg very useful in forest management. Density management diagrams based on the allometric model are simple and effective procedures to display the complex dimensional stand development relationships and to translate general management objectives into stand-specific thinning prescriptions. This study presents a comprehensive approach based on the allometric model to manage the development of Pinus pinaster even-aged stands in Portugal using National Forest Inventory data of 1998. The self-thinning allometric model is a linear limiting relationship between N and dg. It requires upper boundary plot selection and corresponds to the use of the upper confidence interval limit for the intercept coefficient with a slope coefficient of . The upper and lower limits for the optimum growth-density interval also requires attention. In this study trees square spacing and a 10 cm reference diameter were selected to calculate limits that are respectively 63 and 32 . Two associated relationships dominant height and total volume isolines were developed to allow evaluation of thinning regimes in terms of age height and volume. Three alternative management regimes unthinned commercial and precommercial aiming a 30 cm target diameter were discussed and compared. Mortality was only predicted in the unthinned regime accounting for 46 total yield loss. The 30 cm target diameter was reached considerably earlier in the .

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