Microfibril angle variation in red pine (Pines resinosa Ait.) and its relation to the strength and stiffness of early juvenile wood
Publication Name: Forest products journal
Tracheid microfibril angle (MF-angle) of dominant and codominant red pine (Pinus resinosa Ait.) was studied through age 20 in a 57-year-old plantation and in a 42-year-old natural stand in eastern Maine. In the plantation, mean ring MF-angle decreased with age from 30 degrees at age 2 to 15 degrees at age 20. In the natural stand, MF-angle decreased from 30 degrees at age 2 to 18 degrees at age 20. In both stands, MF-angle decreased from earlywood to latewood, and the difference between earlywood and latewood MF-angle increased with age. The correlation between both the flexural strength and stiffness of juvenile wood and MF-angle was negative, with bending MOE more sensitive than flexural strength. Both properties were positively correlated to specific gravity. The results suggest that cultural practices that increase ring width early in stand development may increase MF-angle and reduce modulus of rupture and modulus of elasticity.