To establish permanent transects in any type of vegetation is time-consuming; in forest this method takes from two to four hours per transect with two persons. If specific questions are asked that page 88

Fig. 2: Chart of tree bases in permanent forest transect on Lady Alice Island, Chickens group. (See Tables 1, 2.)

can be answered by such transects, their siting is likely to be more effective. There is sometimes value in selecting extreme situations for long-term study. A factor to consider when deciding the number of transects is the amount of time a future worker is likely to have for recording, particularly when the transects are on islands or mountains.

The basic parameters mentioned have been numbers of individuals according to size classes for each species, trunk circumference of trees > 2 cm dbh, and canopy cover. Any additional parameters can be recorded, depending on the aims of the study. In order to reduce the chances of error, a record of the original field measurements page 89 should be kept as well as the data for derived variables such as dbh or basal area.

Sometimes it is possible to mark the positions and measure plants in the vicinity of but outside a transect. In this way sample size can be increased so that a particular species population is sampled adequately. Individual plants can be labelled, care being taken to ensure that wiring on the label does not restrict future growth.

Other types of repeated observation can be made in permanent transects apart from those relating to live plants. For example, the decay rates of fallen branches from different species in various environments is a topic about which little is known. The unexpected results which permanent transects sometimes produce, amply reward the observer for the time he takes in their recording.

Finally it must be emphasised that recording vegetation in a permanent transect invariably has some modifying effect on the plants, particularly when more than one person is recording. Every care should be taken to minimise this disturbance.

Acknowledgments

I thank Mr A. E. Ester of Botany Division, D.S.I.R., for encouraging me to publish this paper. Discussion with Mr Esler, Mr R. G. Bagnall of Victoria University and Mr A. P. Druce, Botany Division, D.S.I.R., helped to clarify several aspects of the procedure suggested.