To determine water use traits during vegetation succession in Ziwuling forest zone on the Loess Plateau,we selected three native deciduous tree species:Populus davidiana,Betula platyphylla (early succession species) and Quercus liaotungensis (climax succession species) from Ziwuling forest zone as the materials,and compared their hydraulic architecture traits including specific conductivity (K^s),leaf specific conductivity (K^l),Huber value (HV) and the vulnerability to embolism,etc.The results showed that:(1)Q.liaotungensis had lower saturated osmotic potential (Ψ^sat),osmotic potential at turgor loss point (Ψ^tlp),relative water content at turgor loss point (RWC^tlp) and higher leaf capacitance (C^leaf) than that of P.davidiana and B.platyphylla.(2)Quercus liaotungensis had higher maximum K^s and lower HV than that of early succession species P.davidiana and B.platyphylla,thus maximum K^l for these three species was the same.(3)For both leaf and branch,Quercus liaotungensis was more resistant to embolism than P.davidiana and B.platyphylla,meanwhile,Q.liaotungensis also had a larger hydraulic safety margin when balanced by the difference of minimum leaf water potential during dry season (Ψ^min) and xylem water potential corresponding to 50% loss of conductivities (Ψ⁵⁰),and larger leaf hydraulic protection for branch when estimated by the difference between leaf Ψ⁵⁰ and branch Ψ⁵⁰.(4)No hydraulic architecture difference was found for two early succession species P.davidiana and B.platyphylla.These results demonstrated from plant hydraulics that higher dehydration tolerance,larger leaf capacity,stronger leaf and branch embolism resistance,higher hydraulic safety at Q.liaotungensis may be responsible for its higher drought tolerance compared with early succession species P.davidiana and B.platyphylla.