Rating effectiveness of herbicides in desiccating woody vegetation

When the effectiveness of herbicide desiccants for killing and drying woody vegetation on many small test plots is rated, the standard procedures for collecting fuel moisture samples are time consuming and costly. Also, the field data often must be recorded when weather is not suitable for collecting moisture content samples. To overcome these limitations, a new procedure was devised for systematically evaluating appearance of leaves, twigs, and small stems and estimating quantitatively the percent of total small-fuel mass that was dead or dying and would eventually dry to low moisture content. This small-fuel rating provides a means of determining an approximate Potential Equilibrium Moisture Content for the small-fuel mass - its moisture content after drying to equilibrium under atmospheric conditions suitable for prescribed burning. With the small-fuel ratings and limited moisture content sampling of larger stems, it is possible to select those herbicide treatments most effective for desiccating the entire mass of woody vegetation.