Abstract: A pot culture experiment with two clones of poplars (P₁ and P₂) showed that soil salinity had a definite inhibitory effect on the establishment and growth of seedlings.The survival rate,seedling height and weight,and root weight were all declined with increasing soil salinity.When the salinity was 0.2%, 0.4%,0.6% and 0.8%,the shoot growth of P₁ and P₂ decreased by 23.24%,48.56%,70.76% and 83.33%,and 71.77%,83.25%,86.28% and 91.39%,respectively,in comparing with the control.Regressive analyses showed that soil salinity had a linear relationship with chlorophyll content, and a binomial relationship with leaf proline content. The activities of soil β-glucosidase and L-asparaginase were decreased with increasing soil salinity.When the salinity was 0.2%,0.4%,0.6% and 0.8%,the β-glucosidase activity in P₁ and P₂ soils decreased by 10.96%,20.07%,30.96% and 37.44%, and 11.21%,18.94%,34.89% and 41.31%,respectively.The salinity tolerance of P₁ was better than that of P₂.

Key words: Petrophytia moss, Forest vegetation, Disturbance, Water and soil conservation