A Sampling System for Poplar Insects

The distribution of poplar foliage over the trees is described for a number of locations in the trans-Divide area of the Rocky Mountains of Canada. The statistics of some foliage attributes and of the distributions of a number of organisms infesting foliage are derived. On this basis, a sampling\u27 system with preset limits of precision and confidence is designed. The system is tested and its limitations discussed. Techniques for the modification of the system to fit local conditions are suggested. The system outlined will provide in a single operation data of known accuracy on the populations of a number of organisms