Dangerous Trees: Are You Liable?

If you own or manage property in London, you’ve already got plenty on your plate. From leaky roofs and boundary disputes to sorting out planning permissions, the list of headaches never really ends. But as a certified London arborist who spends every day looking at the capital’s canopy, I can tell you there’s one massive risk that often flies completely under the radar: your trees.

The Occupiers’ Liability Act & What London Landowners Need to Know About Dangerous Trees

Sure, trees look fantastic and provide much-needed green space in the city, but a dodgy tree isn’t just an eyesore; it can land you in serious legal trouble. It all comes down to a piece of legislation called the Occupiers’ Liability Act. Fundamentally, the Occupiers’ Liability Act places strict statutory responsibility directly on the landowner for any harm caused by dangerous trees.

In this article, we break down exactly what that means for you, your leafy assets, and your bank balance.

You’re on the Hook: The Legal Nitty-Gritty

Here’s the reality. If you own or manage land in the UK, you owe a legal “duty of care” to anyone who sets foot on your property.

The Occupiers’ Liability Act 1957 dictates that you must ensure your lawful visitors, the postie, a visiting friend, your tenants, or a delivery driver, are reasonably safe on your land. But it goes further than that. The Occupiers’ Liability Act 1984 actually extends that duty of care to people who aren’t explicitly invited onto your property, including trespassers.

If an old, rotting oak tree in your front garden suddenly gives way and flattens a parked car, or worse, seriously injures a pedestrian walking past your boundary wall, you are the one footing the bill. You can be sued for negligence if it turns out you knew, or realistically should have known, that the tree was a hazard.

In this type of scenario, you can’t just play dumb. “I didn’t know it was going to fall” isn’t a valid get-out-of-jail-free card if the tree was visibly rotting away for months. The law expects you to keep a responsible eye on your property.

For commercial landlords, schools, and estate managers, the legal burden extends even further. The Health and Safety at Work Act 1974 requires the management of tree risks across public and workplace areas to be a strict statutory duty. Ignoring these assessments leaves your organisation exposed to huge liability.

How to spot a Dangerous Tree

So, how do you know if a tree is about to give up the ghost? You don’t need a Level-4 diploma in arboriculture to spot the worst offenders, but you do need to pay attention. Keep your eyes peeled for these classic warning signs:

• The ‘Widowmakers’: It’s a grim name for a seriously grim problem. We’re talking about large, dead branches that have snapped but are just hanging out up there, caught in the canopy or barely clinging to the trunk. One stiff breeze during a London winter storm is all it takes to bring them crashing down onto whatever or whoever is below.
• Fungus and Mushrooms: Spotting toadstools sprouting around the base of the trunk, or large fungal brackets growing straight out of the bark, isn’t just a quaint woodland feature. It’s often a massive, flashing warning sign that the tree is decaying from the inside out. Wood-decay fungi literally eat the structural fibres of the tree, turning solid, load-bearing wood into mush.
• Deep Cracks and Sudden Leans: If your tree has developed deep, open splits in the main trunk or has suddenly started leaning heavily to one side after a storm, its structural integrity is badly compromised.
• Root Heave: Have a look at the ground around the base of the tree. If the soil is suddenly lifting or cracking on the side opposite the tree’s lean, the root plate is failing. The tree is losing its grip on the earth and could topple at any moment.

Why a “Quick Look” Isn’t Enough (The Tech Saves Trees)

Spotting a mushroom is one thing, but knowing exactly what’s happening inside the trunk is a totally different ballgame. A tree can look the picture of health on the outside, with a full canopy of green leaves, yet be completely hollow and structurally compromised on the inside.

This is where professional Visual Tree Assessments (VTA) come in. If our consultants spot a red flag, we don’t just guess. We use advanced, non-invasive diagnostic tech to map out the decay.

Using PiCUS Sonic Tomography, we send sound waves through the trunk to create a full-colour, 3D map of the internal wood density, think of it as an MRI scan for your tree. We also use Resistograph micro-drilling to precisely measure timber strength. This hard, scientific evidence tells us whether a tree needs to be felled immediately for public safety, or whether it’s perfectly sound and can be saved, saving you unnecessary felling costs.

When Do You Actually Need a Tree Safety Report?

You shouldn’t just wait for a massive branch to snap before taking action. Here is when you actively need to get the professionals in:

1. Routine Due Diligence: For residential properties with large trees near buildings or roads, a professional inspection every 3 to 5 years is the gold standard for proving you are meeting your legal duty of care.
2. Post-Storm Checks: After severe London weather or high winds, you need immediate stability checks to ensure root plates haven’t shifted and the canopy is secure.
3. Buying or Selling a House: If you’re purchasing a property with mature trees, mortgage lenders and insurers will frequently demand a Mortgage Tree Report (or Homebuyer Hazard Check) before they sign off on the loan or policy. They want to know the trees aren’t a subsidence risk or an immediate falling hazard.

Don’t Leave It to Chance

Crossing your fingers and hoping for the best during the next gale simply isn’t a risk management strategy. Proving that you’ve taken your legal responsibilities seriously means getting your trees checked out by qualified arboricultural consultants. You need a defensible, documented paper trail to show you’ve done your due diligence.

If the worst happens, having a recent, professional report on your behalf proves to your insurer and the courts that you acted responsibly. At London Tree Surgeons, our Level-4 consultants provide actionable advice, and our reports are backed by a robust £2 million professional indemnity insurance policy .

Don’t wait for a storm to expose your liabilities. To ensure you are fully compliant, protected, and keeping the public safe, book a comprehensive Tree Safety Report in London today.