Radial and longitudinal density variations in Abies cephalonica and Pinus halepensis

Basic wood density is an excellent indicator of quality, it is correlated with numerous physical, physiological and mechanical characteristics of a species and is a good descriptor of wood quality and important indicator of tree performance in community ecology. An accurate method is thus needed to estimate wood density. The standard way is to calculate the ratio of the oven-dried mass of a wood sample divided by its green volume, but wood characteristics within and between growth rings are highly variable; the density can vary in the longitudinal and the radial directions. The present study investigates the longitudinal and radial fluctuations in the basic density of Abies cephalonica Loud and Pinus halepensis Mill. Four logs were cut from four different trees for each species and 16 discs were formed (two discs from each log, one at the base and one at the top). Each disc was cut into cubes where their distance from the pith was measured and then sorted into 2 cm wide concentric zones. The results revealed a mild decreasing trend in basic density from the foot of the trunk upward for both species. The pith in both species also seems to have a relatively high density, which in the immediate next growth rings decreases only to resume increasing toward the bark.