Interclonal, Intraclonal and within Tree Variation in Wood Parameters of Different Clones of Populus deltoides

Variation in specific gravity and wood parameters was studied in 10 year old trees of 18 clones of Populus deltoides with promising growth rate. The sample discs were taken out at different heights viz. breast height, 25%, 50% and 75% of merchantable tree height. To study radial variation, each annual ring was sampled. Significant interclonal differences were observed in anatomical parameters and specific gravity while trees, within clones showed no significant effect. The specific gravity was found to be positively correlated with age, fibre length and vessel frequency and negatively related with fibre diameter and lumen diameter. A negative correlation was also observed between specific gravity and ring width. Within a tree, height and position of annual ring from pith had significant effect on fibre length, lumen diameter, vessel frequency and specific gravity. The specific gravity reaches maximum at 50% of tree height and fibre length at 25% of tree height showing decreasing trend upwards. At breast height fibre length and specific gravity increases rapidly pith outwards upto 6th year followed by a slower rate of increase upto 8th year with a tendency to level off from 8th year. Breast height values of specific gravity and fibre length have been found to be highly correlated with whole tree values for these two parameters. For the prediction of whole tree values from breast height values, regression models and multiplication factors have been derived for fibre length and specific gravity.