A simple model to examine the impact of changes in wood traits on the costs of thermomechanical pulping and high-brightness newsprint production withradiata pine

A number of functions were investigated that related the costs of thermomec hanical pulp (TMP) and high-brightness newsprint production, using Pinus ra diata D. Don, to important pulp and paper quality (breeding objective) vari ables, including specific energy consumption and pulp handsheet tear and te nsile strength, brightness, and opacity. Pulp handsheet quality traits were considered to be reasonable two-dimensional predictors of paper quality tr aits in this context. A specific production process that requires the use o f a reinforcement kraft pulp and an artificial clay filler to improve the q uality of paper produced from the bleached TMP fibres was investigated, sim ilar to the production process used by Australian Newspaper Mills' Boyer Mi ll in Tasmania, Australia. Pulp and pulp handsheet quality variables could be explained by significant (P > 0.05) wood traits using multiple linear re gression equations. This provided a method to predict the economic importan ce of each wood trait in relation to the thermomechanical production proces s investigated. The results showed that tracheid length, wood density, wood brightness, and tracheid coarseness were the best predictors of costs. Inc reases in tracheid length, wood density, and wood brightness and decreases in tracheid coarseness resulted in decreasing the total costs of TMP and hi gh-brightness newsprint production.