VISUAL GRADING OF SMALL-DIAMETER POPLARS FOR PEELING USE.

Small-diameter poplars (Populus euramericana, or Populus deltoids, or Populus nigra) are an important raw material resource for the wood and paper industry. Both manufacturers and governments are increasingly interested in obtaining this raw material from poplar plantations. A small-diameter poplar is between fifteen and thirty five centimetres in diameter at breast height. In this study small-diameter poplars were graded visually for use in peeling. Traditional rules currently in use were applied when grading small-diameter poplars, and standard layer-sorting rules were used on the outputs from the peeling process. The field study has shown that standard sorting by layer doesn't correspond well when small-diameter poplars are sorted. For instance, the best small-diameter poplar is rarely classified as class A or B by standard layer sorting. In this research, small-diameter poplars are classified accurately using specific, alternative rules, and the grading scale ranges are presented. Some defects, such as knot and splits, have a strong influence on the quality of the final product, but often, existing standard-sorting methods do not reflect the degree to which the defects have affected the final product. A new method for classifying small-diameter poplars is presented, which groups the wood by its value in the final product. [ABSTRACT FROM AUTHOR]