Abstract: The crown structure, biomass production and dry matter distribution of M.glyptostroboides plantations are studied.The results show that there exists a great difference in crown structure for plantations of various stand density and age.The branch angle is gradually decreased with the rising of crown location and increasing of stand density.The location of largest crown layer and the photosynthesis center of the crown gradually rise with the increasing of DBH.DBH bears close relationship with the crown weight and ratio of branch and leaf.However, DBH is in directly proportion to the crown weight and inversely proportional to the ratio of branch and leaf.The biomass production, distribution pattern of dry matter and economic biomass in the plantations are greatly affected by stand age and planting density.The accumulation trend of aboveground biomass, stem,branch and leaf in the plantations could be described by the use of Richards model.With the stand age increasing, the ratio of distributing the dry matter to the stem increases,but decreases to the branch and leaf.The economic biomass production for architectural timber is in order of 625>2500>1250 plant·ha^-1, and for pulp--making timber is in order of 2500>625>1250 plant·ha^-1 at 15 years.

Key words: Metasequoia glyptostroboides, Crown structure, Biomass production, distribution pattern, Economic biomass