On fluting of the trunk in young trees of Pinus taeda L. (Loblolly Pine) with an appendix on the measurement of radial growith as ring-width

Abstract

Appearance of fluting of the trunk in young trees of Pinus taeda L. (loblolly pine) from Queensland is due to near alignment of greatly extended depressions produced by suppression of radial growth above and below the insertion of branch-bases. Inclination of the fluting accompanies inclination of grain (spiral grain) in the tree.

This suppression, chiefly of early wood, operates for 2–3 years and differs from the very slightly extended suppression associated normally with dead branch-bases on both normal and abnormal trees. A pathological condition of the cambial zone seems to affect not only the quantity but also the structure of the cells formed.

In the two butt logs examined, suppression ocourred only in the growing seasons beginning 1948, 1949, and sometimes 1950. After that, the depressions were being obliterated by local excess of radial growth, mainly in apparent late wood, and the surface would probably have appeared undisturbed by the end of the season beginning 1955 or 1956 (trees about 18–20 years old).

In a note on measurement of "radial growth" at a grooved surface, of the three possible measurements of ring-width, namely, radial (along the radius of the tree-as-a-whole), histological (along the direction of the rows of wood cells), and apparent (along the shortest distance across the ring), the histological ring-width is suggested as most correctly representing "radial growth". The implied "stepped" arrangement of the cambium is demonstrated.