Effects of Silvicultural Practice, Tree, Cambial Age and Height on Wood Density Components of Plantation Poplar I-69 (Populus Deltoides CV. I-69/55) in China

Abstract

In the study, the testing material of 6 trees of poplar clone I-69 (Populus deltoides CV. I-69/55) trees aged 12 years old were selected from the stands which located on the beech of Yangtse River in TianChang city, Anhui province, China. The wood density components (overall wood density (WD), earlywood density (DEW), latewood density (DLW) and relative wood density (DMax-DMin and DLW-DEW)) were measured using microdensitomitry methods. The effect of silvicultural practice, tree, cambial age and height of tree on wood density components was analyzed respectively. The results are as follows:1. The effect of silvicultural practice on wood density is significant at the 1% level, but not significant on earlywood density, latewood density and relative wood density.2. The tree effect on wood density, earlywood density, latewood density and relative wood density is not significant.3. The cambial age effect on wood density is significant at the 5% level, very significant on earlywood density, latewood density and relative density at the 0.1% level. There are large differences for radial variation patterns of wood density in 6 trees. In general, it has two kinds of radial variation patterns like increasing from pith to bark and decreasing outward at different heights. The wood density within a growth ring increases from earlywood to latewood continuously, but there exists large alteration when the cambial age is less than four years.4. The height effect on wood density including earlywood density and latewood density is significant differently in different trees. The wood density in the bottom (below 2m) is lower than the upper one (above 2m). The DMax-DMin fluctuated heavy below 2m and above 5m, but the DLW-DEW increases from bottom to 2m height and levels off upward.