チッ素含有率からみたスギ枝葉の区分

Sugi (Cryptomeria japonica) branches were divided according to three methods of classification : (1) the diverging part, (2) branch order, and (3) branch age. The relationships between the N(nitrogen)-concentrations and the distance from the top of the branches or the diameter of the branches were examined. N-concentrations in leaves, twigs and branches decreased from the top to the base of the branch. N-concentrations in leaves, twigs and branches were also related to the diameter of the branches in each span. The N-concentration of the third order branch was the highest, and that in the first order branch was the lowest. The N-concentraion in the branches changed according to the branch age ; that of a one year branch was the highest. The criteria of classification between leaves and branches corresponded to O.8% in N-concentration and 4 mm in the diameter of the branches.