Microwave attenuation as an indicator of sampling weight of herbaceous and woody plants in the field.

Abstract

Attenuation of microwave signals was linearly related to the weight of herbaceous plants and woody shoots less than 1.27 cm diameter along the transmission path in spruce-fir, northern hardwood, and mixed-wood stands. Hand-held instrumentation gave results equal to those obtained when rigid mounts were used. Signal loss was more closely related to green weight of vegetation in hardwood stands and to dry weight in softwood stands. Signal loss also was linearly related to annual growth of herbaceous and broadleaf woody vegetation. -Authors