A topophysic relation between regrowth and pruning in Eucalyptus cladocalyx F. Muell

Abstract

Stems of Eucalyptus cladocalyx F. Muell. 60 ft high were cut back to 30,15, or 7ft. Some stems were in addition notched at 24, 15, and 7 ft. After 1 year the lengths of the longest shoots at the cut ends could be correlated with the distance between the shoot and the base of the trunk and with the initial height of the tree. Similar relations were found for the oxygen uptake of bark below the cut ends, and for the number of shoots arising below the notches.

Since these attributes were acquired by virtue of the situation of the shoot, they represent an extreme form of topophysis.

The length of shoots arising spontaneously down the stem was curvilinearly related to position, with a maximum length at 15 ft. The length of shoots arising below notches exhibited a similar trend; these shoots were longer.

Attributes which could not be associated with position were shoot number, both at the cut ends and arising spontaneously down the stems, and leaf shape.

There were no interactions between the several stems arising from a single trunk.