Snow-gum dieback has been observed across much of the Australian Alps. Each observation of dieback adds to our understanding and ability to respond. One of the most valuable ways to help is by reporting observations of dieback. While observations from remote locations are particularly valuable, all observations help.
Reporting dieback is simple, just click the Report dieback button at the top or bottom of this page, or on the main page of this website and;
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record the location of your observation (or let your device geolocate it for you)
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upload one or more photos of the tree/s on which you've observed dieback (images must clearly depict the indicator/s of wood-borer infestation that suggest snow-gum dieback is occurring).
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Before reporting an observation, review the key indicators and signs associated with snow-gum dieback.
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Recognising dieback
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Whether it is a cause or consequence of tree decline, the type and extent of wood-borer damage is central to describing snow-gum dieback. Field observations have shown that infestations follow a clear progression, and several identifiable features reflect that progression. While the early stages of snow-gum dieback can be hard to identify, the later stages are unmistakable.
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Early indicators
Infestations are first indicated by tiny entrance holes, ~1 mm wide. They can be very hard to spot and easily are confused with the holes left by small shoots. Over time, growing longicorn larvae create short chains of small (3-4 mm wide) circular holes. These holes are spaced ~3-5 cm apart and are arranged horizontally or vertically. The holes allow frass (chewed-up wood) to be pushed out of the feeding gallery under the bark. Frass with the appearance of sawdust is occasionally present around the holes. The holes may also be leaking a deep reddish exudate known as kino.
Horizontally arranged frass holes
Vertically arranged frass holes
Intermediate signs
As the feeding of larvae below the bark progresses, the overlying bark dries, puckers and cracks. A subtle depression in the bark may also indicate the exact position and size of the underlying feeding gallery.
Collapsing bark overlying galleries
Splitting bark overlying galleries
Late stages
Progressively, patches of bark die completely, splitting open to reveal the feeding galleries. These galleries are evident as deep horizontal scars across the stem. In the most advanced infestations, slabs of bark fall off affected trees leaving the scars associated with feeding larvae fully exposed. Scars remain obvious on affected trees decades after the stem has died.
Recently exposed galleries
Galleries on dead stem
All uploaded observations are reviewed by SOSnowgum. Observations are excluded from mapping if they do not include evidence of wood-borer damage or are clearly incorrectly geo-located. Common issues arise when observations are made from a place of residence after visiting a sub-alpine area. In these instances images of sub-alpine woodlands are incorrectly geo-located and cannot be used.
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