A tree which has a risk that's so high it's Not Acceptable or Not Tolerable will usually be large, have an Obvious Tree Risk Feature, AND be in a high-use zone.
Tree Risk Management is how a Duty Holder goes about managing the risk from branches or trees falling to an Acceptable or Tolerable level.
Trees give us many benefits that we need. But, they're natural structures that sometimes fall over or shed branches; usually because of severe weather.
Tree managers and owners have a Duty or Standard of Care to manage the risk from their trees. The Duty also says they should be reasonable, proportionate, and reasonably practicable when managing the risk.
That means there's a balance they need to strike between the many benefits trees provide, the risk, and the costs of managing the risk. By taking a balanced approach, they don't waste resources by reducing risk - and losing benefits - when the risk is already Acceptable or Tolerable.
The most effective way for a Duty Holder to discharge their Duty of Care is to adopt a Tree Risk-Benefit Management Strategy, that includes a Policy and a Plan.
Compared to other everyday risks we readily accept, the overall risk to us from branches or trees falling is extremely low.
Our annual risk of being killed or seriously injured is less than one in a million. That's so low, we're at greater risk driving on about a 400km/250mi round trip to visit friends for a weekend than from branches or trees falling over an entire year.
Driving for about 400km/250mi = 1 micromort, which is a one in a million chance of dying.
Given the number of trees we live with, and how many of us pass them daily, being killed or injured by a tree is a rare event; one that usually happens during severe weather.
Tree risk is about the risk from branches or trees falling. It has three variables to it. Two likelihood variables and one consequences variable.
1) The likelihood of a branch or tree falling
2) The likelihood of someone or property being there when the branch or tree falls
3) The consequences of the tree part hitting someone or property
What is the risk from branches or trees falling?
Compared to other everyday risks we readily accept, the overall risk to us from branches or trees falling is extremely low. Our annual risk of being killed or seriously injured is less than one in a million. That's so low, we're at greater risk driving on about a 400km/250mi round trip to visit friends for a weekend than from branches or trees falling over an entire year. Given the number of trees we live with, and how many of us pass them daily, being killed or injured by a tree is a rare event; one that usually happens during severe weather.
Duty holders who don't have a strategy explaining how they manage the risk from tree failure are vulnerable to legal claims or enforcement action. Even though we know the overall risk of death or serious injury from tree failure is extremely low, a number of recent Coroner's Inquests from around the world have highlighted why having a strategy in place is so important.
Death on the highway, from the Arboricultural Association's Arb Magazine (Summer 2020), takes a closer look at the importance of Tree Risk-Benefit Management Strategies to the duty holder.
Here's a LinkedIn article about the landmark Cavanagh v Witley Parish Council Judgment. It explores the gulf between reasonable, proportionate, and reasonably practicable tree risk management and assessment, and expert evidence in some UK court Judgments.
Poll v Bartholomew 2006
Every summer, when we get long hot dry periods, concern is often raised about the risk from Summer Branch Drop (SBD). Fear not. We’ve got the risk management of SBD covered for you in our free Summer Branch Drop (SBD) Guide.
Is this SBD?
In brief, the overall risk from SBD is mind-boggling low. What that means is there’s no need to fret about putting up signs, or fencing, or pruning, unless you have a tree that’s a repeat offender.
Have a look at our Risk Management page for lots more free and handy common sense tree risk management advice and help.
When a tree might be 'dangerous'*, it'll usually have obvious features (not tree defects) that you can't help but notice.
To help you spot trees that might be dangerous, here's an illustrated Obvious Tree Risk Features Guide for you to download.
We're a not-for-profit and this is released under a creative commons licence, so we're more than happy for you to share it around.
*Dangerous = where the risk is not Acceptable or Tolerable.
A short piece about why we shouldn't use 'risk of harm' when talking about tree risk.
The risk of harm?
'Tree Defect' no longer appears in any of VALID's Tree Risk-Benefit Management Strategies.
Want to know why we're 'ditching the defect' here, and the App is going to have a ? added to D for DEFECT? Click the link to this short article to find out.
Taking the 'Defect' out of tree risk-benefit management strategies
You can keep up with all latest news about tree risk by staying in touch.
We'll send you an occasional short dispatch from the front line every few months or so.
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