Grasstree (Xanthorrhoea preissii) recovery after fire in two seasons and habitats

Abstract

To distinguish fire-stimulated growth from the underlying growth patterns imposed by season, we measured leaf production of Xanthorrhoea preissii Endl. (Xanthorrhoeaceae). We compared unburnt with spring- and autumn-burnt sites in forest and woodland habitats. Following fire, X. preissii responded with accelerated leaf production, regardless of season. Rapid leaf production during the initial flush of growth was partly at the expense of starch reserves in the stem, at least after autumn fire. Although this initial flush was relatively short-lived after fire in both seasons (12–32 weeks), the effect of fire on leaf production was sustained for up to 20 months, accompanied by a significant reduction in leaf longevity. Mean maximum leaf production rate was higher for spring-burnt grasstrees (up to 6.1 leaves day–1) than those burnt in autumn (up to 4.5 leaves day–1), associated with seasonally optimal growing conditions in late spring–early summer. Similarly, the timing of autumn burns in relation to declining temperature with the approach of winter appeared to dictate how rapidly grasstrees recovered. The consequences of fire season could have implications for the reproductive success of X. preissii.

Fitness and evolution of resprouters in relation to fire

“…However, such trade-off is only clearly established between the resource demands of vegetative growth and storage organs (Pate et al 1990;Schutz et al 2009). Stored starch is used for post-fire root and shoot recovery (Bowen and Pate 1993;Langley et al 2002;Korczynskyj and Lamont 2005;Schutz et al 2009), but can also be used for supporting inflorescence production in the case of grasstrees (Lamont et al 2004) and some geophytes that flower before foliating (Ruiters et al 1993;Lamont and Downes 2011).…”

The role of grass-tree Xanthorrhoea semiplana (Asphodelaceae) canopies in temperature regulation and waterproofing for ground-dwelling wildlife

“…Lamont et al 2000), it may be overestimated by some. Starch loss may reduce resprouting success after fires depending on season (Korczynskyj and Lamont 2005). Tozer and Keith (2012) demonstrated that a single fire interval of 17 years resulted in the local extinction of Xanthorrhoea resinosa.…”

Strategies to acquire and use phosphorus in phosphorus-impoverished and fire-prone environments

“…obs.)] and mycorrhizal [e.g., Macrozamia riedlei (Zamiaceae) (Grove et al 1980), Xanthorrhoea preissii (Xanthorrhoeaceae) (Korczynskyj and Lamont 2005)] pyrophilous species. While possibly not essential, mycorrhizas might play a role in P acquisition immediately after a wildfire.…”

“…They are among the first to resprout and grow fast after a wildfire (Fig. 5), and then their growth declines to very slow rates (Grove et al 1980;Korczynskyj and Lamont 2005;Lamont and Downes 1979).…”