• Roos, Kenneth D.
  College of Forest Resources, University of Maine, Orono
  
• Shottafer, James E.
  College of Forest Resources, University of Maine, Orono
  
• Shepard, Robert K.
  College of Forest Resources, University of Maine, Orono
  

The effect of age on the properties of wood from 12 mature quaking aspen trees was investigated to determine the influence of juvenile wood on the specific gravity, strength, and stiffness of the material. A diametric section, removed from the butt log of each tree, provided material for density profile and microbending test specimens. The mechanical properties evaluated were modulus of rupture and modulus of elasticity. Segmented regression and graphical analyses were employed to estimate the transition age from juvenile wood and the point of maturity, as reflected by the properties evaluated. The length of the juvenile period, about 16 years, and the point of maturity, at age 30 years, appeared consistent for the characteristics investigated.