tailieunhanh - Báo cáo khoa học: "An overview of oak silviculture in the United States: the past, present, and future"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "An overview of oak silviculture in the United States: the past, present, and future. | Ann Sci For 1993 50 535-542 Elsevier INRA 535 Original article An overview of oak silviculture in the United States the past present and future R Rogers 1 PS Johnson 2 DL Loftis 3 University of Wisconsin Stevens Point Wl 54481 2 USDA Forest Service North Central Forest Experiment station 65211 Columbia MO 3 USDA Forest Service Southeastern Forest Experiment station Asheville NC 28802 USA Received 6 January 1993 accepted 2 June 1993 Summary Oaks Quercus are important components of forest systems throughout the United States. This overview describes past present and future silvicultural practices within the oakhickory ecosystem of the United States. Past land-use activities favored oak development but wildfire and livestock grazing controls have caused severe oak regeneration problems that were not recognized until for weedings cleanings and the use of stocking charts to control intermediate thinnings were early silvicultural developments. More recently growth and yield models for managed stands were developed to predict current and future timber volumes. Currently silviculturists are developing solutions to natural and artificial regeneration problems. Research results indicate that other factors being equal regeneration success is favored by simultaneously reducing over and understory densities and that oak seedling survival and development is enhanced in large seedlings that have high root to shoot ratios. Future silvicultural practices will have an ecosystems focus. oak silviculture regeneration thinning model Résumé Un aperẹu global de la sylviculture des chênes aux États-Unis passé present futur. Aux États-Unis les chênes Quercus constituent partout des composants importants des sys-tèmes forestiers. Ce travail a pour but de décrire les pratiques anciennes actuelles et futures à I in-térieur de 1 écosystème chêne-hickory des États-Unis. Autrefois les activités réalisées dans I utilisa-tion des terres favorisaient le développement des .