Heartwood extractives of phyllocladus trichomanoides

Abstract

Wood is of plant origin. Plants may be woody or non-woody, but the criteria for their division into two categories is quite specific. Woody plants are essentially vascular; that is, they possess a specialised conducting system consisting of xylem and phloem; the xylem being the wood of the plant. They are perennial, and possess a stem or trunk which his the ability to persist throughout the life of the plant and also to increase in thickness from year to year. Whilst there are a vast number of plants which conform to the above general criteria for being woody in nature, there are only a comparative few of the required form and stature which will produce wood on a commercial scale. Lumber-producing trees and trees which are chemically utilised are confined to the spermatophytes, which are seed bearing vascular plants as opposed to those that are spore bearing. The spermatophytes are further subdivided into the Gymnosperms and the Angiosperms, depending on the manner in which the seeds are borne, and, at the present time, the Angiosperms, in the point of view of numbers, vastly outnumber the Gymnosperms. However, one particular order of the Gymnosperms, the Coniferales, produce trees commercially productive of wood, and they form by far the largest group of species for lumber production. They are the so-called 'softwoods' of commerce.