Species comparison of the physical properties of loblolly and slash pine wood and bark

Composition of the southern pine forest is now predominated by two species, loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.), owing to fire suppression activities, natural regeneration on abandoned agricultural lands, and extensive planting. Comparison of the wood and bark physical properties of these pines is of interest in terms of the yields of usable biomass and, for the bark, its ecological functionality on a living tree. Trees from a species comparison study were used to generate wood and bark property data, on a whole-tree basis, and for stem disks collected at breast height. Models were constructed to explain the effect of relative height on wood and bark properties. When comparing the whole-tree data, slash pine wood (0.523 versus 0.498) and bark (0.368 versus 0.311) specific gravity values were higher, both offset by lower moisture contents; slash pine also produced a higher percentage of bark on a dry-mass basis (17% versus 12.5%). Unlike wood properties, bark properties showed significant between-species differences when determined at breast height alone, the exception being moisture content. In terms of yield, harvests of a green tonne of loblolly pine and slash pine would give approximately the same dry mass of wood, but slash pine provides more bark.