Critical buckling height and stand variation in Pinus

Although elastic similarity models and determinations of critical buckling height often consider density-specific stiffness to be constant, few studies have tested this assumption in plantation-grown trees. Waghorn and Watt combine theory with field data to test the assumption across a stand-density gradient for Pinus radiata exhibiting a wide range of stem diameters, slenderness and modulus of elasticity. They find that critical buckling height is highly responsive to decreasing diameter and increasing slenderness, and the results suggest that within-species density-specific stiffness variation may influence critical height and the scaling exponent between critical height and diameter, which is considered to be an important factor in assumptions regarding allometric relationships.