杨树萌芽更新及持续生产力

Coppicing Techniques of Poplars and Sustainable Production

:根据杨树萌芽更新特性生产纸浆、能源及刨花板等木材原料是一种轮伐期短、产量高、投资少的重要经营方式。笔者从杨树萌条的发生形式、影响杨树萌芽更新能力的因子、影响萌条生长的因子、杨树萌芽更新林分的生产力及萌芽林分持续生产力的维护等 5个方面阐述了杨树萌芽更新的技术和生产力的维护。杨树萌条的发生形式以萌芽条为主 ,根蘖条相对较少 ,且萌条大多成簇状分布 ;杨树萌芽更新能力与伐桩年龄、轮伐期长短、伐桩粗度、采伐季节密切相关 ,而与伐桩高度关系不大 ;萌条的生长状况 ,除受遗传性状的影响外 ,还与立地条件、萌条发生部位及时间、采伐季节、每桩萌条多少及轮伐次数等因素有关 ;萌芽更新林分的生产力与造林密度、轮伐期长短、每桩留萌数量及萌芽代数密切相关。另外 ,针对影响萌芽林分产量的内外因子 。

Poplar has many characteristics that make it suitable for plantation forestry when compared to other forest species, such as fast growing, adaptability to different environmental conditions and to different silvicultural systems. All of which enable the production of large quantities of wood in short periods of time, which can be used for different forms of processing in the timber industry, in the pulp and paper industry and as a source of energy. Based on a lot of investigation materials of poplar coppicing system, this paper mainly deals with coppicing techniques of poplars and sustainability from five aspects, e.g. shoot producing meristems, factors affecting the ability to resprout, factors affecting coppicing growth, productivity of the coppicing system and the sustainability of the system. The reasons for using coppice systems in poplars are the relatively high production potential of the coppicing system, and the economically favourable propagation technique using unrooted stem cuttings. The investigations have revealed that the resprouting may originate from different kinds of buds at the base of stems or from the roots; these are either preventitiuos or adventitious buds. However, most of the sprouts in the poplar coppicing system are stump sprouts. The key factors to affect resprouting ability in poplar are stump age, rotation length, stump diameter and the harvesting season, while the growth of sprouts and the productivity of coppicing system are affected by genetic characters, site condition, location of the sprout appearing, harvesting season, number of sprouts reserved on each stump, and the generations of coppicing system. Several leading silvicultural measures in poplar coppicing system were also proposed in order to establish a sustainable plantation in this paper.