dieback

The recent Snow Gum Summit in Jindabyne has drawn attention to the health of this notable tree of the Australian alps. The causes or primary cause of widespread snow gum decline, with a particular focus on fire regimes, climate change and insects, and the appropriate response to this problem, are the subject of a considered exchange of differing views here between two experts from different generations but not entirely different schools or schools of thought.

Leading scientists have issued a dire warning that the widespread death of a key eucalypt species in Australian ecosystems could be imminent, due to global heating. Scientists from eminent institutions recently gathered at the Snow Gum Summit in Jindabyne to discuss combating the loss of an iconic tree of the Australian Alps, the Snow Gum.

Dr Brookhouse and the Snow Gum Summiteers (Snow gum dieback raises fears for largest river system) should look at the history and basic ecology of chronic eucalypt decline or so-called dieback ... Pests, parasites and diseases are symptoms and contributors, not causes of chronic eucalypt decline ... Chronic decline of eucalypts is not a consequence of climate change.

Scott O’Keeffe. Around 15 years ago, people living in the Maleny area of Southeast Queensland noticed a decline in the health of some large mature bunya pines (Araucaria bidwillii). The crowns of the trees began turning brown, quickly followed by foliage well below the crown. Within a short time, all foliage would be shed, branches cast, and the affected tree would be dead ... Araucarian Dieback (AD) is on the move.

Man’s best friend is being used to help identify a dangerous pathogen killing native Australian plants in parks around Perth and in conservation reserves and national parks in south west WA. Phytophthora (cinnamomi) dieback is known as the “biological bulldozer”.

Frank Batini. I have observed patterns of foliage scorch, some tree deaths and then recovery in the northern jarrah forest for 22 years. These can be readily explained in terms of soil depth, water-holding capacity, winter rainfall and summer drought ... My hypothesis is that this forest has repeatedly shown resilience to drought ... This is the “good news”, as opposed to the alarmism of other commentators.

John O'Donnell reviews eucalypt decline and dieback in relation to the lack of low intensity fire management across Australia. John considers that exclusion of frequent low intensity mild fire is the primary cause of eucalypt decline in Australian native forests and woodlands and this has been inadequately recognised ... This lack of recognition is in itself a major environmental issue and ignores up to 60,000 years of Aboriginal burning practices across the landscape.

There was nothing new or unexpected about the recently announced NSW Natural Resources Commission research on timber harvesting and koalas ... There’s nothing in the NRC report that actually deserves a tick. It’s a well-established historical and scientific fact that koalas are an irruptive species which responds positively to soft new growth ... Declining trees continuously resprout soft young growth until they eventually run out of resources. Koalas breed up in declining forests.