Variation of Anatomical Features in Tension Wood of Kalopanax septemlobus

Three trees of tension wood of Kalopanax septemlobus (Thunb.) Koize (the lean angle was 10°) taken from a natural stand were divided into three portions:tension wood (T) far away from the pith, opposite wood (O) near the pith and side wood (S) between T and O to study their radial and axial variation of wood anatomical features. The results show that the radial variation patterns are "increasing first, then levelling off" for fiber length and "decreasing first, then levelling off" for microbrillar angle in the three portions of tension wood. But their intermediate periods from "increasing or decreasing" to "levelling off" of S, O and T are different, in which 17 years for S and O, and 22 years for T. M eanw hile, the radial variation patterns of tissue proportion and the axial variation patterns of anatomical features of tension wood in three portions are different.