How to tell whether a tree is sick or diseased tree

Unfortunately, trees are vulnerable to a range of diseases and pests that can compromise their health—or in some cases, lead to their decline or death.

Early detection is key. Spotting the warning signs of a struggling tree can help you take action before the issue becomes severe, and may even prevent the need for removal altogether.

Common Signs Your Tree May Be Unwell

Unusual Leaf Appearance

Look closely at the leaves. Discolouration—such as yellowing, browning, or odd hues—can signal nutrient deficiencies, fungal infections, or environmental stress. Leaves that are curling, wilting, misshapen, or dropping early (outside of the usual seasonal cycle) may indicate pest activity, disease, or a stressed root system.

Bark and Trunk Irregularities

The bark is another key indicator of a tree's health. Cracks, flaking, cankers, or peeling can all suggest disease, damage, or decay. Pay attention to any sudden changes in texture or colour. The presence of bulges, swellings, or fungal growths (such as mushrooms or conks) on the trunk or near the base may point to internal rot. Oozing sap or a sticky residue can also be a red flag.

Root Zone and Stability

Issues at ground level are often overlooked. Visible root damage, exposed or rotting roots, soil movement, or a leaning trunk can all be signs that the tree’s root system is compromised. This not only affects its health but may also pose a structural risk.

Branch and Canopy Health

Dead or leafless branches during the growing season suggest poor vitality. A thinning canopy, slow or stunted growth, and changes in the tree’s overall shape are signs that the tree could be under stress. These symptoms may be caused by disease, poor soil conditions, or pest infestation.

Signs of Pests

Pests such as borers, aphids, or caterpillars can do significant damage if left unchecked. Look for signs like small holes in the bark, frass (insect droppings), chewed leaves, or the insects themselves. Left untreated, infestations can seriously weaken the tree.

Speak to the Professionals

If you spot any of the above warning signs, it’s best to seek advice from a qualified tree care expert. At The Original Tree Surgeons, we bring over 40 years’ experience in tree and garden management. We offer free consultations and expert advice to help you understand what’s happening and what options are available.

From diagnosis to treatment and ongoing care, we’re here to support you in maintaining healthy, safe, and beautiful trees all year round. Regular checks and early intervention can make all the difference in preserving the trees on your property.

If you have any questions or are worried about a tree on your property, talk to us today: 020 8088 5202

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