A sick tree caught at the right stage can sometimes be treated or managed, while a dying tree that goes unnoticed becomes a safety issue and, eventually, an emergency removal.
Here are the common signs, we as professional tree removal and safety surgeons, look for to check if a tree is unhealthy or not.
What the bark tells you
Tree bark is where most problems first show on the outside.
A healthy tree has bark that is firm and attached securely to the wood beneath, while disease, rot, and physical damage all leave visible changes to the bark before showing up anywhere else.
Loose bark and surface cracks
Loose or missing sections, vertical cracks running the length of the trunk, or areas where the bark lifts away from the wood are all signs of damage or disease.
Minor fresh bark damage from a strimmer or mower can sometimes be stabilised by taping it back into position temporarily while you wait for a professional assessment.
Weeping sap and canker lesions
Dark staining, weeping sap, or bleeding lesions on the bark signal bacterial or fungal infection inside the trunk.
Canker diseases cause sunken, discoloured patches that spread outward from the point of infection.
Either of these on a mature tree means the bark condition and the wood beneath it both need a professional look.
Leaf and canopy warning signs
Yellow leaves out of season
Yellow leaves in autumn are normal. In June or July, they’re a sign the tree is suffering.
Nutrient deficiency, waterlogged roots, and fungal disease all produce early yellowing.
Whether the yellowing appears on one side or spreads evenly across the full canopy points toward different causes, and that pattern is usually the first clue toward a diagnosis.
Dead twigs and brittle branches
Dead twigs at the tips of branches are an early warning sign.
A handful scattered through the canopy may indicate drought stress. Dead twigs and brittle branches concentrated in one area, or progressing steadily inward from the outer growth, suggest active dieback from disease or pest infestation.
A complete lack of green in sections that should be leafing out in spring means those branches are already dead.
Whether the dieback progresses further into the canopy depends on identifying and addressing the cause.
Leaves growing on one side only
A tree producing growth on one side only, with the other side showing dead or bare branches, is a sign the tree is experiencing structural or vascular failure on that side.
The pattern often means disease or pests have invaded the tree’s internal system and are blocking the flow of water and nutrients.
When one side of a tree fails while the other looks healthy, the problem is inside the trunk, not in the surrounding environment.
Dead leaves that stay on in winter
Dead leaves that remain attached to the tree’s branches through winter, rather than falling in autumn as they should, are a recognised sign that something is wrong.
Living branches drop their leaves as part of normal dormancy. Dead branches hold onto theirs.
Root problems and soil changes
Mushrooms and fungal growth around the tree
Mushrooms or toadstools growing around the base of the tree, or directly from exposed roots, indicate fungal activity in the root system.
Some surface fungi are harmless, but fungal growth connected to the root zone can signals root decay.
Bracket fungi growing directly from the trunk, or appearing at the same point repeatedly around the tree, are a more serious sign.
They form on the outside only after the internal decay has already progressed significantly, so their presence means the problem has been developing for some time.
A leaning tree
Trees develop a gradual lean toward light over years of growth. A tree that develops a sudden lean is a different matter, and a new lean is often a sign that it has already lost significant root support.
A leaning tree with cracked or heaving soil around the base needs urgent professional assessment, not continued monitoring from a distance.
Root damage from construction or landscaping
Any work that can injure tree roots within the drip zone of the canopy, including excavation, hard landscaping, or utility installation close to the base of the tree, reduces the tree’s capacity to take up water and nutrients.
Trees that lose roots to excavation or landscaping near the drip zone often show no symptoms until the following growing season. The dieback appears above the affected root zone first and moves outward toward the outer canopy as the problem develops.
Fungus, rot and internal decay
Root decay and internal rot can kill a tree from the inside without leaving obvious external signs until the damage is severe. This is particularly bad for oak trees.
Fungal spores enter through damaged bark, pest galleries, or wounds from storms or pruning, and begin breaking down the wood from within.
Soft, spongy, or discoloured wood at the base of the trunk indicates internal rot. Poking the base with a screwdriver should meet firm resistance. If it sinks in without effort, the wood is dead or decaying.
Bracket fungi, the shelf-like growths that appear on tree trunks or at the base, signal that internal decay is already at an advanced stage. The structural wood is already severely compromised by the time they appear on the surface.
Where the tree cannot be safely retained, removal is usually the practical outcome.
The longer a rotten tree stands, the less predictable it becomes under wind or frost loading.
Sick tree or stressed tree?
Stress and disease produce many of the same visible signs, and the distinction matters because the responses are different.
A tree is sick or dying when it has an active pathogen, pest, or structural failure that is directly killing tissue. Environmental stress is a different category, where conditions like compacted soil, poor drainage, or drought reduce the tree’s ability to function without directly attacking it.
For a tree to recover from stress, the underlying cause needs to be addressed. Soil compaction can sometimes be relieved, and drought stress caught early gives the tree a chance to recover.
None of these interventions make sense without knowing what is actually causing the decline. The right care starts with an accurate diagnosis, and causes and responses vary significantly between tree species.
Can you save a sick tree?
The answer is, it depends.
A tree specialist should assess the tree before any decision about treatment or removal is made. Whether it can be saved depends on how much sound timber and healthy root system remain, and on what is causing the decline.
What looks like a recoverable tree from the outside might have extensive internal failure, which is why a professional assessment matters before any action is taken.
Our priority is always safety and protecting the local ecosystem.
Here are two of our major solutions to a sick tree.
Bracing and cabling
Where the tree is structurally sound but leaning, it may be possible to brace it to keep it stable.
Bracing and cabling reduce the risk from weak limb unions and heavy branches without requiring removal.
Our arborists can assess whether bracing is safe, or whether the structure has already declined too far for that approach to hold.
When removal is the right answer
When removal is the right answer, a dead tree on your property is a safety liability. Call a certified arborist before the tree comes down on its own.
A controlled removal costs considerably less and carries far less risk than dealing with a tree that fails without warning.
A tree with a Tree Preservation Order or in a conservation area is subject to strict regulations. Always consult with a tree expert or your local Council before tackling a tree by yourself.
Why a certified arborist should evaluate your tree
A thorough arborist assessment covers bark condition, canopy health, root stability, internal decay, and structural loading, because these factors interact with each other in ways that aren’t visible from the ground.
Working through all of them is the only way to get an accurate picture of what the tree needs.
Tree surveys and written reports
Our certified arborists carry out tree surveys for residential properties, commercial sites, and estate grounds across central Scotland and Glasgow.
A tree survey gives you a written report on the health of a tree or a full site, clearly showing which trees need work and which are safe to leave.
Catching a problem when a tree is still manageable is considerably cheaper than dealing with an emergency callout after a partial collapse.
Tree services from an Arboricultural Association-accredited team produce documented records of tree damage and condition, and those records matter if a tree later causes an insurance claim.
The earlier you arrange an assessment, the more options remain available.
Signs your tree is unhealthy: your questions answered
How do you know if a tree is stressed?
Stress shows in the leaves and canopy first. Wilting or yellowing during normally wet periods, early leaf drop, reduced leaf size, and sparse canopy growth are common early signs. Compacted soil, severed roots, extended dry spells, and waterlogging are the most frequent causes.
Can a dying tree still have leaves?
Yes. A dying tree can still produce leaves in the first season after a serious root or structural problem develops. The stored energy in the trunk and branches fuels that growth even when the root system is failing. However, a dying tree will often show full leaf on some branches with dead or bare sections alongside, rather than an even decline across the whole canopy.
Can you bring a sick tree back to health?
Sometimes. Trees with early-stage fungal disease, nutrient deficiency, or drought stress can recover with the right intervention. The aim is to nurse the tree back to health first, and consider removal only when the assessment shows the tree is already too far gone for treatment to be viable.
How can you tell if a tree is unsafe?
The most immediate signs of an unsafe tree are a sudden lean, cracking at the base of the trunk, large dead branches directly above areas people use, and visible root failure. Avoid spending time underneath trees that show any of these signs until a specialist has evaluated them. An unsafe tree is not always a dead or dying one.
Book a tree survey with GGM Landscaping
We carry out tree surveys across central Scotland for private homeowners, estates, and commercial grounds. If you’ve noticed any of the signs above on a tree at your property, reach out to GGM Landscaping.
Our tree surgery team covers everything from pruning and tree care through to safe removal where that’s what the assessment shows.
All work is carried out by City & Guilds NPTC certified arborists across central Scotland.
Protect your trees and protect your property with GGM Landscaping. Call 07946 322717 to arrange a free quote today.