The Effect of Low Temperature during Imbibition on Germination Characteristics of Tetracentron sinense (Tetracentraceae) Seeds Effects of Altitudes and the DBH of Seed Trees on Biological Characteristics of Tetracentron sinense (Tetracentraceae) Seeds Effects of different geographical provenances and matrix on seed germination and seedling initial growth of Tetracentron sinense The Effect of Low Temperature during Imbibition on Germination Characteristics of Tetracentron sinense (Tetracentraceae) Seeds STUDIES ON THE CHEMICAL CONSTITUENTS OF THE BARK OF TETRACENTRON SINENSE