Heart Shakes and Growth Stresses


  • Peter P. Gillis
  • Alan K. Burden


Heart shakes are often observed to accompany crosscutting of tree trunks and have been thought to be due to release of longitudinal strain energy in the trunk during cutting. Using a simple model of stresses in the trunk, the authors have attempted to link shake development quantitatively with release of axial strain. On the basis of the analysis, however, it appears unlikely that there is a direct relationship between the two. A more likely cause is the transverse stress concentration caused by the saw cut.


Boyd, J. D. 1950a. Tree growth stresses. I. Growth stress evaluation. Aust. J. Sci. Res. Series B—Biol. Sci. 3(3): 270-293.nBoyd, J. D. 1950b. Tree growth stresses. II. The development of shakes and other visual failures in timber. Aust. J. Appl. Sci. 1(3): 296-312.nGillis, P. P. 1972. Theory of growth stresses. Submitted for publication.nHearmon, R. F. S. 1948. The elasticity of wood and plywood. For. Prod. Res. Rep. No. 7. H.M.S.O. London.nKubler, H. 1959a. Studies on growth stresses in trees. I. The origin of growth stresses and the stresses in transverse direction. (In German). Holz Roh- Werkst., 17(1): 1-9.nKubler, H. 1956b. Studies on growth stresses in trees. II. Longitudinal stresses. (In German). Holz Roh- Werkst., 17(2): 44-45.n






Research Contributions