Abstract: A study was carried out to assess the influence of multi-stem phenomenon on cumulative volume and cone yield in 40-year-old Pinus koraiensis plantations. Four stand density levels (600, 750, 900 and 1200 trees·hm^-2) were sampled (15 plots in 25 m×40 m) to determine the relationships between stem types (single stem, two branching stems, and three or more branching stems) and stand density, tree height, diameter at breast height (DBH), crown diameter, mast year cone yield using one variable Logistic model and Meta analysis. The frequency of multistemmed trees decreased as the stand density increased. The frequencies in the stands of 750, 900, 1200 trees·hm^-2 were reduced by 24%, 51% and 59%, respectively compared with that in the stand of 600 trees·hm^-2. The frequency of double multi-stemmed type that exceeded 60% was the highest among the three multistemmed types. The multistem phenomenon had significantly promoting effect on DBH, tree height, crown diameter and cone number per tree by increasing 2.12%, 4.69%, 4.89% and 29.57%, respectively, compared with non multistemmed trees. The multistemmed types had different effects on cone production and tree height, DBH and crown diameter. The DBH, tree height, crown diameter and cone number per tree of single multistemmed trees were 1.49%, 1.99%, 1.47% and 20.64% higher than those of non multistemmed trees, respectively, but there were no significant differences. The doublestemmed and multiplestemmed trees had significant positive effect on cone production and stand growth indexes. The tree height of doublestemmed tree and multiplestemmed trees were increased by 2.07% and 2.90%, respectively; the DBH increased by 6.00% and 6.09% respectively; the crown diameters increased by  6.29% and 5.99%, respectively; the cone number per tree increased by  34.61% and 26.22%, respectively. In conclusion, the results of Logistic regression and Meta analysis suggested that the multistemmed trees had evident promotion effect on cone production, in which multiplestemmed trees and doublestemmed trees had more significant effect on tree growth and cone production. The multistem effects decreased with the increasing stand density. The highest multistemmed effect was observed in 40-year-old Korean pine plantation with the stand density of 600-750 trees·hm-2.

Key words: diffuse flux, stable carbon isotope, production pathway, Tuojia River, CH₄