Characteristics of stemwood and their manipulation

Abstract

Wood has a variety of uses. Each has a particular set of requirements regarding its quality and has to contend with a variable wood resource even after selection. However, a quality resource for chemical pulping may not equate necessarily with desirable material for particleboard manufacture or even for mechanical pulping. This is fortunate as the differing criteria for various markets allow each industry to compete for that part of the wood resource which it can use best. The prices that are tendered as a consequence of their differing assessments of the quality of a particular resource determine who eventually purchases that material. A sawmill will pay more for a large butt log than for an equivalent volume of smaller wood, because sawn timber can be cut more economically from large logs and a better grade of timber is obtained. The fibres in the slabwood from a large butt log differ little from those in the adjacent sawn timber and are ideal for making strong paper by kraft pulping. A pulp mill can procure slabwood chips at a fraction of the price for sawlogs from which they are derived. Small top logs are very satisfactory for mechanical pulp and particleboard manufacture while yielding a less strong but adequate kraft pulp.