Australia only has a tiny portion of it’s landmass which is sub alpine or alpine. We know that climate change is already impacting on mountain environments, and without meaningful action to reduce greenhouse emissions, this will only continue.
The true alpine zone, that area above the treeline, is tiny relative to the landmass. The tree line is the highest elevation that sustains tree growth and is around 1,800 metres above sea level in mountain areas on the mainland (lower in Tasmania). The tree line is mainly defined by the gradual disappearance of snow gums (Eucalyptus pauciflora), which are a type of Eucalyptus that can withstand the severe cold and dry conditions of the mountains. The tree line is defined by temperature, not altitude, which explains why Australia has a lower tree line than most other countries.
As the climate warms, it can be expected that snow gums will be able to colonise the open alpine terrain above. This will lead to the loss of the true alpine vegetation, as these communities are ‘pushed off the top’ of the mountains and replaced by snow gum woodland. New research sheds light on this process, and has shown the role that fire plays in how snow gums encroach of alpine zones.
A research paper titled ‘Alpine treeline ecotone stasis in the face of recent climate change and disturbance by fire’ (available here) and authored by Aviya Naccarella, John W. Morgan, Seraphina C. Cutler, and Susanna E. Venn considers the interaction between fire, climate change and the treeline. In short, and as you would expect, this research suggests that more frequent fire slows the rate of colonisation of trees above treeline.
Continue reading “Fire impacts on the alpine treeline” →
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