Half butt eucalypts: how and why they do it
Professor Michael Lawes Charles Darwin University 2015

As Professor Michael Lawes stated in the grant submission: “Eucalypts are super-trees. They have many adaptations for life under harsh conditions but most importantly disturbance by fire. As a rule eucalypts dominate fire-prone ecosystems. Surprisingly, there has been relatively little research on how eucalypts manage to do this and how they cope with fire.”

This project was aimed to understand the relationship between bark type and fire resistance through a study of half-butt eucalypts with a thick fibrous ‘sock’ on the main stem and smooth photosynthetic bark in the canopy (e.g. Eucalyptus miniata), which coexists with eucalypt species that are covered with fibrous or stringy bark (e.g. Eucalyptus tetrodonta).

The findings have now been published as “Bark functional ecology and it’s influence on the distribution of Australian half-butt eucalypts” in Austral Ecology available here.

Here are the main findings from the abstract:

“Butt height at a site, … was not induced by flame height or affected by fire frequency and was approximately half the canopy height of the tree, suggesting it is internally regulated. The half-butt E. miniata and full-bark eucalypts were similarly resilient (survival) under surface fire conditions. Half-butt species predominated in arid and semi-arid bioregions characterised by surface fire, consistent with our proposition that half-butt bark is an adaptation to surface fire, and thin photosynthetic outer canopy bark reduces moisture stress, accounting for the wide distribution of half-butt eucalypts in arid and seasonally dry regions of Australia.”