The aim of this research is to assess the impact of paper birch (Betula papyrifera Marsh.) tree characteristics on wood color variability, grade recovery, and lumber value. Current results are based on 2,284 paper birch boards coming from 168 trees harvested in two different stands in Québec, Canada. Results showed that tree diameter was the most important variable affecting board quality and value. Larger trees were associated with higher board quality and higher lumber value per tree. Lumber value per tree was influenced by tree vigor as well but not by tree age. The most vigorous trees produced higher board value with an average of USD 316.62 per m3, middle vigor classes showed averages of USD 218.28 per m3 and USD 251.84 per m3, while the less vigorous trees had the lowest average with USD 165.94 per m3. Board quality was only partly influenced by tree age and tree vigor. When selected for color, the majority of the board surface area fell under the sap category (50%), while 28 percent was classified as regular presenting simultaneously both colorations, and finally only 4 percent of the board area was classified as red. It was found that the most important variables affecting this board color distribution were tree vigor and tree diameter, whereas tree age also had a significant but lesser impact. In general, older, larger, and less vigorous trees tended to present higher proportions of boards classified in the red category. Finally, the results obtained in this study tend to support the practice of silvicultural treatments aiming to produce larger trees yielding higher value and quality boards.
Contributor Notes
The authors are, respectively, Postdoctoral Fellow, Centre de recherche sur le bois (CRB), Faculté de foresterie et de géomatique (myriam.drouin.1@ulaval.ca), and Professor, Centre de recherche sur le bois (CRB), and Dean, Faculté de foresterie et de géomatique, (robert.beauregard@sbf.ulaval.ca), Université Laval, Québec, Cana-da; and Research Scientist, FPInnovations – Wood Products, Québec, Canada, and Adjunct Professor, Département des sciences du bois et de la forêt, Université Laval, Québec, Canada (isabelle.duchesne@fpinnovations.ca). This paper was received for publication in October 2009. Article no. 10696.