High Garden
Old Rose Road The Reach Westeroshire WR7 4DT
06607 657812 info@highgarden.com www.highgarden.com
Page
Summary	1
Policy	2
Plan	3
Passive Assessment	4
Active Assessment	5
Risk Reduction Work	6
Appendices
Zones of High Confluence	A1
Obvious Tree Risk Features	A2
Summer Branch Drop	A3
What is VALID?	A4

Our tree risk-benefit management strategy
Why and how we're going to manage the risk from our trees and branches falling	This flowchart shows the structure of our Tree Risk-Benefit Management Strategy. Everything follows from the Policy. The Policy sets out our position on trees, their benefits, and the risks. In brief, our Policy says; Trees give us many benefits that we need The overall risk from trees and branches falling is extremely low We can't remove the risk entirely. Trees are living structures that sometimes shed branches or fall during severe weather Our duty of care, when managing the risk, is to be reasonable, proportionate, and reasonably practicable We're going to manage the risk to an Acceptable or Tolerable level The Plan explains how we'll carry out the Policy. We're going to manage the risk by Passive Assessment in all zones of use. And Active Assessment in Zones of High Confluence (high use and large trees).
The Strategy at a glance
Passive Assessment
Picking up on Obvious Tree Risk Features you can't help but notice	Passive Assessment is simply picking up on Obvious Tree Risk Features you can't help but notice as you go about your daily routine. Passive Assessment is our most valuable risk management asset because we carry it out in all zones of use, day in day out, at no additional cost.
Active Assessment | Basic > Detailed > Advanced
Trained assessors looking to find risks that might not be Acceptable or Tolerable	Active Assessment is where we have trained assessors looking for risks that might not be Acceptable or Tolerable. Active Assessment has 3 levels to it that increase in depth of evaluation. The 3 levels are, Basic > Detailed > Advanced. We carry out Active Assessment in Zones of High Confluence every 5 years.
Risk objectives & Risk ratings
Risk ratings are as easy to understand as traffic lights	VALID has applied 'ISO 31000 - Risk Management' and the 'Tolerability of Risk Framework' (ToR) to tree risk-benefit management and assessment, which we've adopted. In ISO risk terms, our 'objectives' are to grow, maintain, and conserve trees because of the many benefits they give us that we need. And, to manage the risk from tree failure to an Acceptable or Tolerable level. We have four easy-to-understand traffic light coloured risk ratings to show how we'll manage the risk. Red Not Acceptable risks will be reduced to an Acceptable level Amber Not Tolerable risks will be reduced to an Acceptable level, but with a lower priority than red Not Acceptable risks Amber Tolerable risks will not be reduced but may require an increased frequency of assessment than green Acceptable risks Green Acceptable risks will not be reduced

Establishing the context
Trees give us many benefits we need	The more obvious benefits that trees give us are visual beauty in the landscape, wood, and the various crops they produce. Wildlife habitat, pollution filtering, and reducing weather and climate change effects are additional values. Trees also have important social value as part of our culture, history, or because they commemorate an important event. As if all these benefits aren't enough. There's an ever-expanding body of scientific evidence that shows trees are essential for our physical health, mental wellbeing, and quality of life.
The overall risk to us from trees and branches falling is extremely low	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 millions of us pass them daily, being killed or injured by a tree is a rare event. A rare event that usually happens during severe weather.
We can't be an insurer of nature or eliminate the risk from trees	Of course, we can't be an insurer of nature. Trees are living structures that sometimes shed branches or fall during severe weather. Since we need the many benefits from trees, we have to accept we can't remove all of the risk. Leaves, bark, cones, nuts, fruits, and small diameter deadwood regularly fall from trees. This natural debris is an Acceptable or Tolerable risk.
Duty of care
Reasonable Proportionate Reasonably practicable	We have a duty of care to manage the risk from our trees. The duty also says we should be reasonable, proportionate, and reasonably practicable when managing the risk. That means there's a balance we need to strike between the many benefits trees provide, the risk, and the costs of managing the risk. By taking a balanced approach, we don't waste resources by reducing risk - and losing benefits - when the risk is already Acceptable or Tolerable.
We all have a responsibility to make reasonable decisions	We're all expected to act reasonably and responsibly. We can manage our exposure to the higher risk from tree failure that happens during severe weather by not going outside. If we go out during severe weather, we're choosing to accept some of the risk.
Risk tolerance
What's an Acceptable or Tolerable level of risk from our trees?	The Tolerability of Risk Framework (ToR) is an internationally recognised approach to making risk management decisions. It's used by duty holders where they manage a risk that's imposed on the public. ToR defines Broadly Acceptable and Unacceptable levels of risk. Between these levels is a region where the risk is Tolerable if it's 'as low as reasonably practicable' (ALARP). Put simply, ALARP means the risk is Tolerable if the costs of the risk reduction are much greater than the value of the risk reduction.
Risk objectives & Risk ratings
Risk ratings are as easy to understand as traffic lights	VALID has applied 'ISO 31000 - Risk Management' and the 'Tolerability of Risk Framework' (ToR) to tree risk-benefit management and assessment, which we've adopted. In ISO risk terms, our 'objectives' are to grow, maintain, and conserve trees because of the many benefits they give us we need. And, to manage the risk from tree failure to an Acceptable or Tolerable level. We have four easy-to-understand traffic light coloured risk ratings to show how we'll manage the risk. Red Not Acceptable risks will be reduced to an Acceptable level Amber Not Tolerable risks will be reduced to an Acceptable level, but with a lower priority than red Not Acceptable risks Amber Tolerable risks will not be reduced, but may require an increased frequency of assessment than green Acceptable risks Green Acceptable risks will not be reduced

Establishing our context
Reasonable Proportionate Reasonably practicable	This Plan, and following sections, explain how we're going to carry out our Policy. We're taking a reasonable, proportionate, and reasonably practicable approach to manage the benefits from trees, so the risk is Acceptable or Tolerable.
We have many trees to manage with limited resources	High Garden covers an area of 500 acres with formal gardens, woodland pasture, and some native woodland. We have 10 Basic Validators. They carry out Passive Assessment, and Active Assessment at a Basic level when needed. All our personnel have a copy of the Obvious Tree Risk Features guide, and they carry out Passive Assessment.
Zones of High Confluence (high use + large trees)
A typical Zone of High Confluence Tree Risk-Benefit Assessment	We're most likely to find risks that aren't Acceptable or Tolerable where we have a combination of high use, in all weathers, and large trees. We call these Zones of High Confluence. They're zones where the highest Likelihood of Occupancy and Consequences merge; Likelihood of Failure is the third element of tree risk. The risk illustrated on the left shows a mature tree in a Zone of High Confluence. Here, we have a very high Likelihood of Occupancy, and a large tree, providing many benefits, that has very high Consequences if it failed. This tree has a very low Likelihood of Failure, and the risk is Acceptable.
Passive Assessment & Active Assessment
Passive Assessment in all zones of use	We manage the risk with Passive Assessment in all zones of use, which we carry out day to day.
Active Assessment in Zones of High Confluence every 5 years	Every 5 years, we'll hire a Validator to carry out an Active Assessment in Zones of High Confluence. Because the overall risk is extremely low, and we carry out Passive Assessment, day in day out. Active Assessment every year, or every few years, isn't a reasonable, proportionate or reasonably practicable approach to managing the risk.
We'll increase the frequency of Active Assessment when necessary	We'll assess trees more frequently than 5 years when a Detailed Assessment has recommended it. If there's an outbreak of a disease. Or where a general decline in vitality is affecting a population of trees.
Risk rating limitations
Risk ratings are limited by the level of assessment	Risk ratings have limitations that depend on the level of assessment at which they're made. For instance, when we carry out Passive Assessment or Active Assessment at a Basic level. If there are no Obvious Tree Risk Features, the risk is Acceptable at that level of assessment. A Detailed or an Advanced Assessment is a more thorough evaluation than a Passive or Basic Assessment. They might find features that weren't apparent at lower levels of assessment, and the risk could be higher. However, carrying out a higher level of assessment, with the additional costs, when there's no obvious feature to trigger it isn't reasonable, proportionate, or reasonably practicable. These risk rating limitations make sense in the same way as your doctor not sending you to a hospital for further tests. At more additional cost. Unless you have symptoms to trigger a higher level of examination.
Severe weather
We'll be vigilant after storms as part of Passive Assessment	If a severe weather warning is forecast, where we can, we'll close the entrances to our parks. If we have any events planned, we'll cancel them. Once the severe weather has passed, all our personnel will keep an eye out for Obvious Tree Risk Features as part of Passive Assessment.
You can take some responsibility for your own risk	Most deaths and injuries from tree failure happen during or just after severe weather. When a severe weather warning is forecast, you can manage your exposure to the higher risk by not going out, and by being watchful just after.

What is Passive Assessment?
Picking up on Obvious Tree Risk Features you can't help but notice	When a tree has a risk that might not be Acceptable or Tolerable it'll usually have an Obvious Tree Risk Feature you can't help but notice. Passive Assessment is simply picking up on these obvious features when we pass by trees whilst going about our day-to-day routines.
Trees with the highest risk are the easiest to find	Passive Assessment is a multi-layered, high volume, and low effort approach to managing the risk. Any trees with a risk that's not Acceptable or Tolerable are most likely to be picked up by Passive Assessment long before Active Assessment. Passive Assessment is our most valuable risk management asset because: Trees with the highest risk are the easiest to find Anyone can do it, from trained assessors to members of the public It's happening in all zones of use, day in day out, at no additional cost Higher use zones are being assessed more frequently than lower use zones because they're visited more often We're doing it after storms when trees that are damaged might now have a risk that's not Acceptable or Tolerable
Passive Assessment tree alerts escalate to Active Assessment > Basic	When we get a tree alert from Passive Assessment. We'll increase the level of evaluation to Active Assessment at a Basic level, by a Validator.
Our people & contractors
Our people passively assess thousands of trees every week	In line with ISO 31000 guidelines and principles, to manage the risk at all levels of our organisation, we carry out Passive Assessment. People in our organisation and contractors we use pass thousands of trees we manage every week. All these trees are being passively assessed, day in day out.
The quality and quantity of Passive Assessment varies depending on who's carrying it out and how they're doing it. For example, Passive Assessment by Validators is higher in quality, but lower in quantity than the rest of the team, and the public. Passive Assessment on foot is higher in quality than when driving, but lower in quantity. Here's how various levels of Passive Assessment quality and quantity work daily at the frontline of how we manage tree risk, with examples.
Basic Validators - Provide the greatest level of Passive Assessment quality because they've been trained. They're passively assessing trees they drive by, or walk past, whilst carrying out their work. Carrying out maintenance near a visitor attraction, a Ranger can't help but notice a broken hanging branch over a low use footpath, after a recent storm.
Arborist Contractors - Let us know about trees they happen along that may need a closer look when they're out there working. Climbing in a tree, an Arborist can't help but notice a large crack on top of a branch in a neighbouring tree that overhangs a car park.
Other Personnel - The highest level of Passive Assessment quantity comes from the rest of our team. They have a copy of the Obvious Tree Risk Features guide. We encourage them to let us know about trees they come across that concern them. On the way to have a lunch break, one of our Admin can't help but notice a split that's recently appeared in the trunk of high use footpath.
The public
Let us know if you think any of our trees might be dangerous	You can download an easy to understand 'Obvious Tree Risk Features' guide to help you work out whether a tree might need a closer look, here.

What is Active Assessment?
Trained assessors looking for risks that are not Acceptable or Tolerable	Active Assessment is when we're looking for risks that might not be Acceptable or Tolerable. It's also triggered when Passive Assessment has picked up a tree that needs a closer look. Or there's some concern about the risk from a tree. We may carry out Active Assessment when we've had a tree work application.
Active Assessment has 3 levels Basic > Detailed > Advanced	Active Assessment has 3 levels to it that increase in depth of evaluation. The 3 levels are Basic > Detailed > Advanced.
Validators can carry out Basic and Detailed Assessments. Their contribution to an Advanced Assessment will depend on the equipment used.
Basic Validators can carry out Basic Assessments to find trees that might need a closer look. They don't make risk rating decisions, but can flag emergency work.
Basic Assessment
Finding the few trees where the risk might not be Acceptable or Tolerable	At a Basic level of assessment, we're looking for trees with obvious features where the risk might not be Acceptable or Tolerable. Occasionally, we'll come across trees that need emergency work. When Passive Assessment or a Basic Validator picks up a tree that needs a closer look, it's a Validator who decides whether to take the assessment level from Basic up to Detailed. Validators can also recognise features that might increase the likelihood of failure. They may evaluate these features with VALID's Tree Risk App, and carry out a Detailed Assessment when uncertain about the risk.
Assessments are made from easily accessible ground	We assess trees from easily accessible ground, by foot, bike, or from a vehicle. If we need to take a closer look at a tree from inaccessible ground, we'll arrange an Advanced Assessment.
We won't remove vegetation unless there's an Obvious Tree Risk Feature	We won't remove climbing plants, undergrowth, basal epicormic growth, or cut hedgerows to get a closer look unless there's an Obvious Tree Risk Feature. It's only if we find any of these risk features the costs of removing vegetation, and loss of their habitat benefits, are justified.
The trees or what they could fall on and the type of assessment will be recorded	Trees, or what they could fall on, and the type of assessment will be recorded. For example, in a park, we might plot and record that we've assessed individual or groups of trees on foot. Whereas, if there are many trees beside a road, we'll record that we've assessed the road.
No Obvious Tree Risk Features The risk is Acceptable	If a tree doesn't have a feature to trigger carrying out a Detailed Assessment, the risk is Acceptable at this Basic level of assessment.
Detailed Assessment
We do a Detailed Assessment when a tree needs a closer look	We'll carry out a Detailed Assessment on trees that need a closer look after a Basic Assessment. Because we have a tree work application. There's concern from the public about a tree. Or we want to show what the risk is on a tree.
The assessment is done from ground level using VALID's Tree Risk App.
We'll produce a report	The App prints a one side report. The report includes the risk rating, risk review year, risk reduction work (if necessary), and any general management advice. When risk reduction work is necessary, we'll record when it's completed.
Advanced Assessment
Large and important trees might be worthy of more effort and cost What we'll do depends on the tree	If we need more information about the likelihood of failure, we'll carry out an Advanced Assessment. Often, we'll do this because we have a valuable tree which has extensive decay. The tree may have significant strength loss and we want to find out whether the tree is strong enough. If the costs of an Advanced Assessment are great, we'll decide whether the tree has enough value and future benefits to justify the costs.
Getting into the tree or onto difficult to access ground	Advanced Assessments include aerial evaluations in the upper parts of a tree. Or to get a closer look at a tree on difficult ground to access.

Risk ratings & risk reduction priorities
We'll prioritise risk reduction work and be practical about it	Risk reduction work will be given the highest priority where it's an emergency. Outside of that, we'll deal with the highest risks first and carry out the work in a sensible order to make the best use of our budget. Red Not Acceptable risks will be reduced to an Acceptable level Amber Not Tolerable risks will be reduced to an Acceptable level, but with a lower priority than red Not Acceptable risks Amber Tolerable risks will not be reduced but may require an increased frequency of assessment than green Acceptable risks Green Acceptable risks will not be reduced
Emergency work
Emergency work will be given the highest priority	If a tree has a very high likelihood of failure and it's in a high use zone, these Not Acceptable risks are 'emergency work'. We'll get a tree crew there as soon as we can to deal with any emergency work.
What we're going to do
First, we'll take stock so we can be cost effective	Outside of emergencies, where we can, we'll not start risk reduction work until we've carried out all our planned Active Assessments. That way, we'll know how much risk reduction work there is, where it is, and how much of our tree management budget we need to spend on it. This will help us prioritise the work, and coordinate it with other tree maintenance so we can plan it in a practical and cost-effective way.
Not Acceptable risks
Risks that are Not Acceptable will be dealt with first	We'll make Not Acceptable risk reduction work the priority. However, we'll do this work pragmatically. For example, we won't send a tree crew from one side of our operating area to another to carry out work where they spend more time travelling than doing the work. We also have to deal with other risks from trees, such as low branches, obscured road signs, and sightlines. If it means we can get more done with our tree budget, we're going to coordinate this kind of risk reduction work with tree failure risk reduction work.
Not Tolerable risks
Other risk reduction will be coordinated with routine work	Where possible, risk reduction work for risks that are Not Tolerable will be organised alongside other tree maintenance works. If there's not enough budget to carry out the both risk reduction and other maintenance work, we'll prioritise risk reduction.
Budget limitations
If we have budget limitations we'll explain them	If we don't have enough budget to carry out all the risk reduction work, we'll record why. Any remaining work will be rolled over to the next budget.
Review
Contractor meetings will be held every month to monitor works	We'll meet our contractors every month and monitor how risk reduction work priorities are being carried out. If we can make any improvements in our work priorities, they will be made here.

Appendices
Zones of High Confluence	A1
Obvious Tree Risk Features	A2
Summer Branch Drop	A3
What is VALID?	A4
High Garden

What is a Zone of High Confluence?
A typical zone of high confluence	We're most likely to find any risks that aren't Acceptable or Tolerable where we have a combination of high use, in all weathers, and large trees. We call these 'Zones of High Confluence'. They're zones where the highest categories of Likelihood of Occupancy and Consequences merge; Likelihood of Failure being the third part of the risk. The image on the left shows a mature tree in a Zone of High Confluence. Here, we have a Very High Likelihood of Occupancy. And a large tree, with many benefits, that has Very High Consequences if it fell. The tree has a Very Low Likelihood of Failure, and risk is Acceptable.
Zones of High Confluence - Measurements
What we mean by 'High use' in zoning	When we work out Zones of High Confluence, the term 'high use', spans the Very High and High Likelihood of Occupancy categories in VALID's risk model. For roads, this is where traffic is 1400 or more vehicles a day.
For people, it's an average of someone passing every minute between 7am – 7pm, Monday to Friday. Which is around 1200 a day.
We zone train or tram lines as high use.
What we mean by 'High Consequences' in zoning	The term 'high consequences', are trees that have a stem diameter of 50cm/20in or more. That's because we're most likely to find risks that are not Acceptable or Tolerable in these larger trees.
Our Zones of High Confluence
We carry out Active Assessment in these zones every 5 years	These are our Zones of High Confluence; All our boundary roads Entrance and exit roads Visitor centre Where we hold events We manage these zones with Passive Assessment, day in day out, and Active Assessment every 5 years.
Zones of High Confluence maps
Our zones of high confluence are marked on maps	The following maps illustrate our Zones of High Confluence. We're managing the risk in all zones with Passive Assessment, day in day out. We'll carry out an Active Assessment in these zones every 5 years.

Photographs Jake Miesbauer, Michael Richardson, Roy Finch, Mark Hartley, Rick Milson, Andrew Benson, David Abrahams Felicity Cloake & Wilf, David Humphries, Jack Prynn, Moreton Arboretum, Josh Behounek, Jan Allen

When might a tree be dangerous?
Trees with the highest risk are the easiest to spot Be watchful after storms	When a tree has a risk that might not be Acceptable or Tolerable, it'll usually have an obvious tree risk feature you can't help but notice. If you come across a tree with anything like these obvious features, it should be looked at by an Arborist (tree expert) who's been trained in tree risk assessment.
Root failure
Storms can break tree roots without blowing them over Signs to look out for are Change in angle of the trunk Large cracks in the soil Hump in the ground on one side
Hanging branches
Don't forget to look up Branches can break during storms and still hang on Sometimes they can get stuck up there for quite a while
A crack or split into the wood, beyond the bark
When trees bend and twist in storms the wood can split and crack Vertical cracks in the bark are just the tree growing well there's no need to worry
Decline & death
To stay healthy and strong trees need 'solar panel' leaves to make food When trees suffer they often have much less leaf cover and many dead branches Standing dead trees have great habitat benefits but need checking
Decay fungi fruiting bodies
To decay fungi these 'fruits' are like apples to an apple tree Decay fungi and trees mostly live happily together creating essential habitat for wildlife Fungi can sometimes 'eat' too much wood and weaken the tree
All you need to know about the risk from SBD
Taking a reasonable proportionate and reasonably practicable approach	This guide looks at what Summer Branch Drop (SBD) is. Fact checks the risk. Reviews what we currently know and don't know. Then provides you with some risk management advice.
What is SBD?
Branches that unexpectedly fail after hot dry weather	SBD is a very loose term for branches on mature trees that have no obvious tree risk features, which unexpectedly fail after a period of hot dry weather.
Fact-checking the risk
The overall risk is mind-bogglingly low	Compared to other everyday risks that we readily accept, the overall risk from SBD is mind-bogglingly low. From the data1 2 we have, the annual risk of death or serious injury is less than one in one hundred million. That's so low, we're at greater risk for the few minutes it takes to cover about 5km/3mi on a drive, than we are from SBD over an entire year.
What we know and what we don't know
There's no agreement about what SBD is or what it's called	Perhaps because the overall risk from SBD is so mind-bogglingly low, it's not been very well researched. There's no agreement about what SBD is, or even what it's called - it's also known as Sudden Branch Drop and Sudden Limb Drop. SBD is most commonly used as a catch-all term to describe branch failure when wind or extensive decay doesn't appear to be an obvious explanation.
There's no agreement about the critical factors that trigger branch failure	In the published literature3 4, there's no agreement about what causes of SBD. There's no agreement about how hot and dry it needs to be, and for how long; or if humidity plays a role. Or whether the branch has to be horizontal or if its length is a critical factor. There's no agreement either about what time of day it's likely to happen, and if rain is required. Or even if the branch has to be free of obvious tree risk features to qualify.
Species profiling and a lack of obvious risk features
Many tree species can suffer from SBD	In the literature, SBD has been recorded on the following species; Ash, Beech, Cedar, Corymbia, Elm, Fig, Eucalyptus, Giant Sequoia, Horse Chestnut, Liquidambar, Oak, Pine, Plane, Poplar, Silver Maple, Sweet Chestnut, Tree of Heaven, Willow. There are probably more species not yet recorded.
We can't tell which branches will or will not fail	Branches that might fail because of SBD, on trees that don't have a history of it, lack any obvious tree risk features. This means an Arborist can't tell the difference between branches that have a high likelihood of failure from those that have a low likelihood of failure, before they fail.
Managing the risk
Unless a tree has a history of SBD the risk is Acceptable Don't put up warning signs like this	If our trees don't have a history of SBD, even at the times of the year when it's most likely to happen, the risk is Acceptable. That means there's no need for us to reduce the risk any further. If any of our trees have a history of SBD, we'll reduce the risk to an Acceptable level by lowering occupancy or pruning.
Warning signs are unnecessary, or not effective. If a tree has no history of SBD, they're unnecessary because the risk is Acceptable. If a tree has a history of SBD, and the risk is not Acceptable or Tolerable, warning signs are not an effective way to manage the risk. They don't pass liability on to a visitor. And we won't be able to demonstrate signs altered visitor behaviour, and level of occupancy, so much the risk was reduced to an Acceptable or Tolerable level. Also, in the extremely unlikely event of someone being killed or injured. It'd be easy for a claimant to make a case we could've managed the risk better, by planting undergrowth, fencing the tree off, or pruning it.
Further information
Want to know more about SBD and risk from tree failure?	1 National Tree Safety Group | Risk Research 2 List of Deaths From Falling Tree Parts in Australia 3 Sudden Branch Drop: A Case for Closer Inspection 4 Summer Branch Drop | Arboricultural Research Note

Simpler • Clearer • Smarter
The Strategy at a glance	Whether you manage or assess tree risk, we're here to help make your life less complicated and more effective.
From Strategy to App, we've got all your bases covered with the first complete tree risk-benefit management system. By taking out bafflegab (vague and ambiguous words) and numberwang (questionable maths that you can easily get wrong) from tree risk, we've made it…
"Uncomplicated…intuitive…simpler…clearer…smarter"
This is what Duty Holders, Arborists, and other team members who we've trained as Basic Validators are all saying. They're some words you'll likely use to describe how you feel after you've validated your approach to tree risk.
Tree risk-benefit management
Reasonable Proportionate Reasonably practicable	Whether you're a Government Agency, Landowner, or Homeowner you have a duty of care to manage the risk from your trees falling or dropping branches. To fulfil your duty, you should be reasonable, proportionate, and reasonably practicable about managing the risk to an Acceptable or Tolerable level.
VALID's got your back here with our full range of ISO 31000 compliant and common sense Tree Risk-Benefit Management Strategies. As part of our not-for-profit goals, we've released all the strategies under a creative commons license. That means they're free and open to everyone. Validators can help you customise your strategy. Or, they have an abbreviated Validator Strategy that covers you and them.
Tree risk-benefit assessment
VALID has been stress-tested to breaking point	Risk-benefit assessments are carried out under the protective umbrella of our Tree Risk-Benefit Management Strategy. The Strategy does more than 95% of your assessments for you. When you need to carry out a Detailed Assessment, you'll use our super smart and intuitive Tree Risk App.
We've built the engine of the App with a Professor of Natural Hazards & Risk Science. The Professor's an internationally distinguished expert in this field. He's test-driven the model to breaking point: "We have stress-tested VALID and didn't find any gross, critical sensitivities. In short, the mathematical basis of your approach is sufficiently robust and dependable for any practical purpose." Willy Aspinall Cabot Professor in Natural Hazards & Risk Science University of Bristol
Tree risk ratings
Risk ratings are as easy to understand as traffic lights	Yes, it really is that clear and easy to understand. There's no confusion about what vague and ambiguous words or complicated numbers mean. We have four easy-to-understand traffic light coloured risk ratings. Red Not Acceptable risks will be reduced to an Acceptable level Amber Not Tolerable risks will be reduced to an Acceptable level, but with a lower priority than red Not Acceptable risks Amber Tolerable risks will not be reduced but may require an increased frequency of assessment than green Acceptable risks Green Acceptable risks will not be reduced
Tree risk-benefit management advice & training
Visit our Training page Or get in touch for help	We work with Duty Holders to help them manage the risk and benefits from their trees. We also train Arborists to become Validators. And personnel who spend a lot of time outside, who aren't Arborists, to be Basic Validators.