Abstract: In order to inquire into potential application of PV (Pressure-Volume) technique to research the dry resistance of tree and compare the differences between young and adult trees in this respect, the dry resistances of young trees of seven species including pinus sylyestris var. mongolica were investigated based on physioligical parameters of dry resistances of their adult trees. The parameters of water conditions in one-year branches of both young and adult trees were measured with PV-curves. They changed with the annual growing processes of the branches. It is relatively reliable and practical that the water parameter of either early stage of young branch growth or the full lignification stage of the branch are considered as the indicators of their dry resistances.The young trees have the less dry resistance than the adult ones during the early stage of young branch growth. There are almost no differences between young and adult trees after the full lignification of the branches.d:\PDF\.pdf

Key words: PV-Technology, Water potential of plant, Osmotic potential, Relative water content, Dry resistance