Wood anatomy and stress distribution in the stem of Pinus pinaster Ait.

F. J. Ezquerra, L. A. Gil


A 70-year-old Pinus pinaster Ait. tree growing in a Spanish forest was cut down and the structure and shape of its crown and trunk were studied. The distribution of longitudinal stresses in the stem due to its self-weight and several wind loading were calculated using the structural theory of a cantilever beam. Wood anatomical features related to its mechanical behaviour (tracheid length, wood density, and heartwood area) were determined in 25 stem slices along the length of the trunk. The longitudinal distribution of stress along the trunk had a peak at 1/4 of the total tree height, and this trend was similar to those of the anatomical features: their maximum values occurred at the same height. This could mean that the tree reinforces its support structure at the point of highest failure risk, where fractures can occur.


Biomechanics; Tracheid length; Wind loading; Stress; Pinus pinaster Ait.

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