Abstract
In a previous paper dealing with duration, rate, and magnitude of elongation of primary, secondary, and tertiary axes in two trees of P. resinosa and one of P. strobus, it was found that: (1) Elongation began at approximately the same time on all branches over the entire contour of the tree. (2) Primary axes showed greater total and higher daily rate of elongation than was shown in any of the secondary or tertiary axes in each of the 3 trees studied. (3) Secondary axes exhibited successively shorter total elongation, shorter duration of growth and slower daily growth rate from the topmost whorl downward. (4) Duration of elongation in the primary axis was greater than in secondaries in P. strobus, but in P. resinosa, duration of elongation in the upper 2-4 secondaries equalled that of the primary axes. All of these data covered the elongation exhibited during the 1942 season only. No other published work dealing with comparison of amount of elongation in primary and secondary axes of pines is known to the writers.
