Abstract: Taking the typical subtropical economic tree species Carya cathayensis and  Myrica rubra in Zhejiang Province as test objects, a pot experiment was conducted to study the photosynthetic characteristics of their seedlings under effects of simulated acid rain with a gradient of pH 2.5, pH 4.0, and pH 5.6 (CK). In the maximum net photosynthetic rate ( A _max ), dark respiration rate ( R _d), light saturation point ( LSP ), and light compensate point ( LCP ) of  M. rubra  were obviously higher than those of  C. cathayensis under no acid rain condition. Under the effects of pH 4.0 acid rain, the A _max  and  LSP of  C. cathayensis  decreased significantly, and the apparent quantum efficiency ( AQE ) of  M. rubra  increased significantly; while under the stress of pH 2.5 acid rain, the A_max and AQE of  C. cathayensis  decreased significantly, and the LSP of M. rubra increased significantly. The effects of acid rain on  C. cathayensis were greater in summer than in spring, and those on  M. rubra  were greater in spring than in summer and autumn.

Key words: Degraded ecosystem, Degradation degree, Succession theory, Vegetation restoration, Chinese pine, Western Liaoning Province