• Ifju, G.
  University of British Columbia, Vancouver, British Columbia
  
• Kennedy, R.W.
  University of British Columbia, Vancouver, British Columbia
  

Microtensile strength of the 36th to 45th annual increments from three Douglas-fir trees was measured and correlated with tracheid length, specific gravity, fibril angle and cellulose content. The variable accounted for 78 percent of the variation in tenacity when springwood and summerwood were considered individually. Typical failures are discussed.