Effects of burning and clipping on temperature, growth, and flowering of narrow-leaved snow tussock

Abstract

Further evidence is given of stimulation of leaf elongation and die back, new leaf production, tillering and flowering following burning of narrow-leaved snow tussock. Tillering began 3–4 months after the fire, during the period of floral induction. Inflorescences were found only in tussocks burnt before mid January. Neither clipping alone nor blackening of clipped tiller bases with aerosol paint promoted flowering to the same degree as did burning. Mulching burnt tussocks to increase insulation and reduce insolation did not alter the tillering or the flowering response. Temperature measurements in tussocks and in inter-tussock soil indicate that recently burnt plants and the soil about them maintain higher temperatures for longer periods and have higher minima during periods of incoming radiation than do untreated tussocks. Increased temperature is suggested as the factor most responsible for altering the behaviour of the modified tussocks. Rapid heat loss at night from the blackened surfaces may accentuate the high day temperature, and increase the induction stimulus.