Weight distribution in the current annual twigs of barclay willow.

Abstract

The current annual twigs of unbrowsed Barclay willow (Salix barclayi Anderss.) grow as gently tapering cylinders. Consequently, the distal half of the twig has only 33 to 41 percent of the total weight. Longer twigs have proportionally less weight in the distal end. The total weight of an unbrowsed twig can be estimated by simple regression of weight on an independent variable that approximates the volume of the twig (diameter of the twig immediately above the most recent bud scar times total length of the twig). Simple regression can also be used to estimate the weight of twig removed by browsing. The best estimator of weight of twig removed is an independent variable that approximates the volume of the twig left attached to the plant (diameter of the twig at the point of browsing times length of twig remaining).

Citation

Thilenius, John F. 1988. Weight distribution in the current annual twigs of barclay willow. Res. Note PNW-RN-472. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research. 10 p