WOOD PROPERTIES OF TEAK GROWING IN HAINAN ISLAND A PRIMARY STUDY ON THE RADIAL VARIATION PATTERNS OF WOOD PROPERTIES WITHIN TREES V.THE RADIAL VARIATION PATTERNS AND ITS VARIATION OF WOOD FIBRE LENGTH OF 15 CLONES OF POPULUS×EURAMERICHANA Quantitative Characteristics of Xylem Cells and Variation in Vessel Element Length and Fibre Length for 13 Psammophytes Study on the Genetic Variance of Wood Basic Density and Fiber Properties of Poplar Hybrids Clone Selection of Chinese Fir with Fast-growth and Superior Timber Property