Spotting snow gum dieback is easy if you know what to look for.
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Here's a guide.
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Snow gums.
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Spotting snow gum is relatively easy, often they are the only tree growing at that elevation. If you are above 1600m, you're probably looking at a snow gum. If the tree shows the dieback symptoms below, and you're not sure if it's a snow gum, make an observation anyway.
​Tree Health.​​​​​
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Healthy: The tree is in good health. The leaves are green and glossy, the bark is smooth and intact, there aren't many epicormic shoots and there isn't any kino (amber sap) leaking out of the tree.
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Stressed: The tree is surviving but something is making its life difficult. Some branches might have yellow leaves, the bark is peeling in some places, there are some epicormic shoots, kino is leaking from some parts of the tree.
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Dying: The tree is dying. The leaves are browning, whole branches have died and have peeling bark, there are many epicormic shoots, large amounts of kino are leaking from parts of the tree.
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Dead: The tree has died. Leaves have fallen off, bark has peeled off, epicormic shoots are withered or gone.
Frass Holes
Boring beetle larvae need to 'go' too. As they munch their way around the tree they leave a trail of sawdust and feces called frass. This begins to pile up and get in their way. In order to clear this away, they drill small holes to the tree's surface through which to expel frass. These are often arranged along the horizontal boring gallery. These frass holes are a clear sign of borer caused tree decline.
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Absent means there are no frass holes.
Present means there are frass holes.
Borer Galleries
Boring beetle larvae cut horizontal channels into the tree's cambium layer, we call these boring galleries. The cambium is the nutrient-rich 'living' layer of the tree just below the bark. As the borer eats its way around the tree, it cuts off the nutrient flow of this outer layer. The result is cracked and puckered bark above boring galleries in the early stages of attack and clearly visible horizontal stripes after the bark has peeled away from a late-stage attack.
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Absent means there are no galleries evident
Present means there are galleries evident
