Abstract:The vertical distribution of cumulative leaf area, bole sapwood area, bole sapwood permeability and sapwood area sapwood permeability, the relationships between cumulative leaf area and sapwood area and between cumulative leaf area and sapwood area sapwood permeability for individual trees of Larix principis-rupprechtii Mayr were examined using a physiological analysis based on Darcy‘s law. Sapwood area and sapwood area sapwood permeability decreased linearly within the crown with increasing height above the ground.Below the crown, the change trend of sapwood area turned out contrary to the sapwood area sapwood permeability, Sapwood area sapwood permeability allowed an accurate prediction of leaf area. The sapwood resistances to water flow from the ground to the 6.5m height above the ground, from the ground to the base of the live crown and from the base of live crown to the 6.5m height above the ground, were respectively 0.93241 atm. s. cm-8, 0.33000 atm.s. cm-8 that was 35.39 percentage of the total resistance and 0.60241 atm. S.cm-8 that was 64.61 percentage of the total resistance.