A simple method for field-based grassland curing assessment

Abstract

The degree of grassland curing represents the proportion of dead material in a grassland fuel complex, expressed as a percentage. It is an important input for models to predict rate of fire spread and determine fire danger levels in grasslands. The degree of curing is currently determined in Australia and New Zealand using a combination of satellite imagery and ground-based visual observations by operational personnel. Both methods present problems. The satellite imagery technique requires updating to accommodate newer satellite technology, as well as extension and validation across all of the major grasslands in both countries. Visual assessments are often both inaccurate and spatially inadequate across the landscape. This paper describes the development of a field-based method to accurately and easily determine curing levels in the field, based on modification of an existing point quadrat method of pasture assessment. This alternative technique minimises subjective assessment by field observers, and involves tallying the number of live and dead touches on a thin steel rod driven into the ground. The average error across sites was lower for exotic improved pastures than native grasslands. Results suggest that this method can be applied across Australasia more accurately than current methods.