How To Tell If A Tree Is Diseased?

Ash tree removal in Tonbridge, Kent

Trees are remarkably capable of expressing how healthy they are. When something is wrong, they display specific symptoms to show us. Learning the signs that our trees exhibit can help us understand how healthy they are. At Broadleaf, we’ve been caring for trees for over 15 years, so we know best how to read a tree. Our experts have put together this article to help you recognise that a tree is diseased and what the common diseases are. But first things first, how can you tell if a tree is diseased? 

The key signs your tree is diseased are abnormal leaf behaviour such as discolouration and early leaf drop, bark deformities such as cracks and missing bark, and dead wood/branches. If you notice these symptoms, you should contact a professional tree surgeon for assistance in treating your tree to keep it flourishing. 

Read on to find out more about how to tell if your tree is diseased with Broadleaf Tree Surgery. 


What Are The Signs Of A Diseased Tree? 

There are some clear signs that your tree is diseased. Knowing what signs to look out for in your trees can help you be aware of unhealthy trees that could cause damage to others on your property.

Bark Deformities 

Deformities or abnormalities in your tree’s bark can indicate disease within your tree. These include: 

  • Missing bark: When a tree is unwell, bark will start to fall off the tree. A healthy tree will regrow its bark, but the bark won’t grow back if it’s diseased. 
  • Vertical cracks: If your tree shows large wounds in the trunk or branches, it can be a sign of disease. Large cracks weaken the tree, making it dangerous as it is more likely to fall. You should remove the tree in this case. 
  • Bleeding cankers: Bleeding cankers are another sign of disease. Fungus-like organisms have infected the bark of your tree and caused a dark or reddish-brown sticky fluid to bleed.

Dead Wood And Branches 

A large amount of dead wood and branches can indicate disease in a tree. As trees decay from the inside, rotting wood is a clear sign of a sick tree. You should inspect your tree for decaying wood or rotting branches so they can be removed for safety. 

Abnormal Leaf Behaviour 

If you’ve noticed unusual signs in your tree’s leaves, this can indicate disease. These signs include: 

  • Yellow and wilting leaves: Leaf discolouration can indicate disease in a tree. If the leaves have begun to die, it shows that the tree has been infected by a bacterial, fungi or viral disease. 
  • Early leaf drop: If your tree loses its leaves prematurely, it is a sign that a disease or pest has infected your tree. 
  • Clinging dead leaves: Dead leaves that cling throughout the colder months can indicate disease, as most trees will lose their leaves due to a temperature change. 

What Diseases Kill Trees? 

Many different diseases can kill all types of trees. The number of diseases attacking trees is increasing rapidly and often leads to the trees dying. The most common diseases that kill trees in the UK are: 

Ash Dieback 

Ash dieback is one of the most common tree diseases in the UK. Over the next few years, it’s estimated to kill 50% of all ash trees in the UK. The spores of the fungus Hymenoscyphus Fraxineus land on healthy leaves over the summer months through westerly air currents. 

This causes small lesions. The infection continues through the leaves into branches and then into the trunk, which then causes larger diamond-shaped lesions to grow. These larger, diamond-shaped lesions cut off the nutrients from the leaves to the trunk, causing the inevitable death of the ash tree itself. Read more about ash dieback on our dedicated blog.

Dutch Elm Disease

Dutch elm disease has killed millions of elm trees in the UK over the past 50 years. Dutch elm disease is caused by the fungus Ophiostoma Novo-ulmi, which causes elm bark beetles to spread.

Elm bark beetles breed in the bark of cut, diseased or otherwise weakened elm trees and then disperse to healthy elm trees, where they feed. As they feed, the spores of O. Novo-ulmi are introduced into the healthy tree’s channels for water and nutrients, releasing toxins and causing the vessels to block and the tree to wilt and die.

Acute Oak Decline 

Acute oak decline is the oak tree’s response to environmental stress. The tree becomes vulnerable to soil conditions and pollution, and then bacteria infects it, pushing it to decline. 

Symptoms of acute oak decline are the tree’s response to stress. The crown becomes thin as leaves are lost, cracks in the bark, and dark bleeds run down the trunk. If the stress is severe or prolonged, the tree can reach a tipping point where it runs out of energy to get through the winter or fight off pests. The trees can die within a few years.

Does Fungi Kill Trees? 

Some types of fungi can kill trees. Most bracket fungi will cause decay and rot in the heartwood of the trees. This type of fungi will weaken the base of the tree, leading to the eventual breakage and fall of the tree. Some spore fungi can kill a tree by affecting the trunk and branches but not the root system. 

If you have a dead tree on your property, our team of experts at Broadleaf are here to help. We will remove any dead trees on your property and remove the waste in an environmentally friendly way. 

How To Tell If Your Tree Is Dead? 

There are some clear, visible signs that your tree is dead. The best way to identify if your tree is dead or not is to give it a full inspection and look out for these symptoms: 

  • Assess the tree for new bud growth across the branches
  • Apply a snap-snatch test on a twig to see if there is fresh green underneath. If not, the twig will be brown and brittle, a sign that the tree is dead
  • Assess the roots for damage and fungi growth 
  • Check for new bark growth where the tree has shed old bark 
  • Look into the canopy for dead branches or missing leaves 
  • Check the trunk for splits, cavities, and cracks 
  • Look for wormwood holes; read more about them in our recent blog

If you notice any of these signs, it’s essential to get your tree assessed by a professional tree surgeon. If you’re worried about your tree’s health, contact us today for a free evaluation.

Professional Tree Surgery With Broadleaf Tree Surgery

Broadleaf Tree Surgery has 15 years of experience in tree care, so if you need help with yours, get in contact with us today. We will provide you with a free estimate on the service that your trees require. 

Alternatively, you can browse our service page to see what we offer or fill out our contact form for more information on our services.


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