马尾松林杆材阶段生物产量和经级分化及密度效应初探

 马尾松(Pinus massoniana)是我国松树中分布最广、数量最多的主要用材和薪炭材树种。它具有适应性强、生长快、用途广，造林成本低和易于成林等优点，是我国南方荒山造林的重要先锋树种，其经济意义、环境防护效能及美学价值，都是为人们所公认的。马尾松的干材成长阶段，是林木胸径和树高旺盛生长时期，林木与生长空间的矛盾及树木间的竞争较剧烈，天然整枝、林木分化和自然稀疏都很强烈。如何调节和控制这个时期的立木密度，使其形成合理的群体结构，对于保证林木成熟期的材积生长和取得最大生物量将具有十分重要意义。本试验目的就在于探明不同密度松树杆材林的生物量、林木分化与产量结构以及不同密度下的生态效应，为确定合理的造林密度和制定疏伐措施提供科学依据。

Preliminary Discussion on Biomass Timber Differentiation and Density Effect of Masson's Pine Pole Stands

Biomass of 14-year old Masson pine timber stands of different densities (2445–4590 trees/ha) was estimated in the hilly area in central Guangxi Province. The results show that the average biomass of individual trees decreases with increasing density within the range of given densities, Biomass of the stands was highest at Ⅱ density group (3210 trees/ha) on the contrary. On the other hand, the annual litterfall increases with increasing density, and the total accumulation of nutrient elements within litter layer increases also with increasing density.