Abstract: Pinus yunnanensis, as an important species of silvicultural and commercial tree, is a kind of special coniferous tree widely distributed in the southwestern part of China. It grows rapidly, and is able to endure poor and dry soil. In this paper, the biomass of natural middle-young stands of Pinus yunnanensis in Yimen county of the central part of Yunnan province at elavations 1600-1700 m have been studied. Authors investigated three stands in the district. Their stand age is 4 -year, 11-year and 23-year respectively.

Key words: Pinus yunnanensis