近自然森林经营在德国的应用成效分析

目的]分析德国推行近自然森林经营20年来的经营效果,总结德国推行近自然森林经营的经验。方法]在明晰近自然森林经营原则的基础上,基于两期(间隔期10年)资源清查数据对比,对德国大面积推行近自然森林经营20年的经营效果进行分析。结果]两期资源清查数据表明,德国采用近自然经营20年后,针叶林如挪威云杉和欧洲赤松的面积显著减少,阔叶林和针阔混交林面积持续增加;阔叶树种蓄积平均增长量约为15 m~3·hm~(-2),针叶树种蓄积平均增长4 m~3·hm~(-2),挪威云杉是唯一蓄积下降的树种,下降了5 m~3·hm~(-2);近自然度等级变化表明,人工林面积在减少,而近自然森林的面积在增加,甚至符合原始林等级的森林面积也在增加。结论]实现近自然森林经营的目标是一个长期的过程,联邦政府促进和保护森林的政策以及林场主所采用的先进的森林经营技术也是德国森林每公顷蓄积达到336 m~3的重要原因;在近自然森林经营的原则下,德国森林中针阔混交林比例显著增加;将近自然程度不高的人工林经营转化为近自然的森林生态系统是德国森林经营所面临的主要问题。

Effect of Close-to-Nature Forest Management Practice in Germany

Objective] To analyze the effect of 20 years''practice of close-to-nature forest management, and summarize the experiences of implementing close-to-nature forest management in Germany.Method] Based on the data of two forest inventories (interval of 10 years), this paper emphatically analyzes the effect of 20 years''close-to-nature forest management practice in Germany.Result] The area of coniferous forests, such as Picea abies and Pinus sylvestris, has been significantly reducing in the past 20 years under close-to-nature forest management, while that of broadleaved forests and coniferous mixed forests continues to increase. All broadleaf species shows an volume increase of about 15 m³·hm^-2 in average, and all conifer species combined also shows a positive change of additional 4 m³·hm^-2, whereas Picea abies is the only species with a decline in volume of 5 m³·hm^-2. Most strikingly is the decrease in area of artificial forests and the increase in the classes close-to-nature and even pristine.Conclusion] Achieving the objective of close-to-nature forest management is a long-term process. Two major factors contributing to the high stock volume of 336 m³·hm^-2 are federal policies which promote and conserve forests and advanced forest management measures adopted by private forest owners. Close-to-nature forest management practice has resulted in an increase of mixed forests; the major challenge faced by German forestry is to convert plantation forests with a lower close-to-nature management level to the close-to-nature forest ecosystem.