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Báo cáo lâm nghiệp: "Dendrochronology of pedunculate oak (Quercus robur L.) in an old-growth pollarded woodland in northern Spain: establishment patterns and the management history"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:"Dendrochronology of pedunculate oak (Quercus robur L.) in an old-growth pollarded woodland in northern Spain: establishment patterns and the management history" | Ann. For. Sci. 62 2005 13-22 INRA EDP Sciences 2005 DOI 10.1051 forest 2004091 13 Original article Dendrochronology of pedunculate oak Quercus robur L. in an old-growth pollarded woodland in northern Spain establishment patterns and the management history Vicente ROZASa b a Departamento de Biología de Organismos y Sistemas Universidad de Oviedo Catedrático Rodrigo Uría 33071 Oviedo Spain b Present address Departamento de Ecología Centro de Investigaciones Forestales y Ambientales de Lourizán Carretera a Marín km 4 Apartado 127 36080 Pontevedra Spain Received 13 November 2003 accepted 19 April 2004 Abstract - Long-term patterns of tree establishment and past management practices in an old-growth pollarded woodland in northern Spain were studied using dendrochronological techniques. Age distribution revealed three main cohorts of pedunculate oak Quercus robur L. 50 years 150-200 years old and 250-500 years old. Juveniles and trees 200-299 years were found to be clumped and spatially segregated from older trees. Oaks older than 300 years showed a random spatial distribution. Mean pollarding intervals had increased through time and the mean number of suppressions per year had decreased significantly. Pollarding frequency and intensity had decreased since 1917 in mature trees and since 1905 in old-growths suggesting a decline of the pollarding practice in the early 20th century. A delay of 6 years in growth releases with respect to growth suppressions was common. This resulted from both strong growth recovery after pollarding and the release of growing space in the canopy. Mature oaks mainly showed 1-3 pollarding signals while in old-growths between 4-7 growth suppressions per tree were more frequent. In 1774 1792 1806 1839 and 1859 small groups of trees and scattered trees were pollarded while in 1905 a generalised reduction of tree growth was noted. The results obtained from this study have significant connotations regarding the preservation and management of formerly