Start with the crown
Look at the top of the tree first, because that is where decline shows earliest. Compare it with the same species nearby — a spotted gum on a neighbouring block on the same soil is a far better reference than a photograph online.
You are looking for thinning: fewer leaves than the tree should carry, light visible through the crown where it used to be dense. Then for dieback: bare twigs and small branches at the outer edges of the crown, working inwards. Outer-crown dieback is the classic early sign that the tree cannot supply its full canopy.
Discoloured, undersized or prematurely dropped leaves point to stress rather than death. Central Coast trees do this routinely after a dry spell, after a wet spell that has drowned the roots, and after a heavy insect year.
Then do the scratch test
Scrape a fingernail-sized patch of bark from a twig. Green and moist underneath means alive. Brown, dry and brittle means dead.
Do it at several points — different heights, different sides. A tree that scratches green on the lower limbs and brown at the top is declining from the crown down, which usually means a root or water supply problem. A tree that is brown everywhere you test is finished.
Look at the trunk and the base
Bark. Large areas of loose, missing or sloughing bark on a species that does not normally shed that way, with no living tissue underneath, is serious. Eucalypts and angophora shed bark naturally, so know what is normal for the species before drawing conclusions.
Cracks and cavities. Vertical cracks in the main stem, open cavities, or a hollow that sounds drum-like when struck all indicate loss of structural wood.
Fungal fruiting bodies. Brackets, conks or mushrooms at the base or on the trunk are the single most important sign on this list. They mean decay fungi are already established inside the tree. The visible fruiting body is the last stage of a process that has been running for years internally.
Root plate movement. Cracked or lifted soil on one side of the base, particularly after heavy rain, indicates the tree is already moving. On the shallow-rooted ground around Woy Woy, the Tuggerah Lakes edge and the Wyong flats this is the warning that matters most.
Eucalypts get more benefit of the doubt
Australian natives are built for catastrophe. Eucalypts carry epicormic buds beneath the bark and can reshoot from apparently bare stems after fire, drought or insect defoliation. Fuzzy shoots emerging directly from the trunk and major limbs are a tree rebuilding, not a tree dying.
That is why a bare eucalypt in late winter is not the same diagnosis as a bare liquidambar. Give the native a season before deciding.
What kills trees here
Root disturbance from building work, driveways and trenching is the commonest cause on suburban blocks, and the symptoms appear one to three years after the damage. Waterlogging kills roots on the low ground. Drought stress opens the door to borers and canker. Soil compaction under vehicles does slow, permanent damage. And root rot pathogens are widespread in coastal NSW — see the tree disease article.
What to do with the answer
If the tree is dead and over something that matters, get it assessed and removed. The signs a tree needs removing article covers the structural indicators, and tree removal services explains the methods. If it is stressed rather than dead, the seasonal checklist covers what actually helps.
Frequently asked questions
What is the scratch test and how do I do it?
Scrape a small patch of bark off a twig with a thumbnail or a knife. Green, moist tissue underneath means that twig is alive. Brown, dry and brittle means it is dead. Do it on several twigs at different heights and on different sides of the crown, because a tree can lose one section and keep the rest. One dead twig proves nothing on its own.
Can a eucalypt recover from losing most of its leaves?
Often, yes. Australian eucalypts carry dormant epicormic buds under the bark and can reshoot from bare stems after fire, drought, defoliation by insects or severe stress. Fuzzy new shoots appearing directly from the trunk and major limbs are a recovery sign, not a death sign. That capacity is exactly why a eucalypt should not be written off as quickly as an exotic.
Is a dead tree urgent?
It depends entirely on what is under it. A dead tree in the middle of a paddock is a wildlife habitat asset and can be left. A dead tree over a house, a driveway, a pool or a boundary fence is a hazard on a clock, because decay progresses and limb attachment fails without warning. Position, not death, is what makes it urgent.
Do I still need council approval to remove a dead tree?
Central Coast Council's vegetation provisions include exemptions for dead and imminently dangerous trees, but the exemption has to genuinely apply and the burden of proof sits with the property owner. Photograph the tree before work and, where there is any doubt, get an arborist assessment in writing. Removing a live protected tree you believed was dead is still an offence.