• Keith, C.T.
  Forintek Canada Corp., Ottawa, Ont
  
• Chauret, G.
  Forintek Canada Corp., Ottawa, Ont
  

A number of basic wood quality characteristics were evaluated in 10 european larch (Larix decidua Mill.) trees, 5 from each of two rapidly growing plantations in eastern Ontario (approximately 30 years old) and western Quebec (approximately 25 years old). Characteristics evaluated included growth rate, relative density, fibre dimensions, longitudinal patterns of variation in wood characteristics were examined and particular attention was given to the distribution of juvenile wood within the stems. Extractive contents were more closely related to the extent of heartwood and sapwood in the stems than to differences between juvenile and mature wood. Relative density was generally lower at the centre of the stem than in the mature outer wood, but the change was usually gradual, with no distinct boundary between juvenile and mature wood zones. The most useful characteristic for delimiting the juvenile wood zone appeared to be longitudinal shrinkage. On this basis, the transition from juvenile to mature wood occurs at about 15 rings out from the pith at breast height. Ranking of individual trees for wood density was judged to be reliable at about 7 years of age at this height level.