Utility Arboriculture Conference

Tree risk management

Simon RichmondTechnical Officer,

Arboricultural Association

Utility Arboriculture Conference

Tree risk management

Simon RichmondTechnical Officer,

Arboricultural Association

Background

• History

• Context

• Benefit

• Risk

• National Tree Safety Group (NTSG)

• Proportionate, balanced response

• Power lines

• Railways

Influencing cases

‘The Birmingham Ash’

Birmingham City Council was fined £150,000 for breaching health and safety law after three people were killed by a falling tree on 3rd December 1999.

The council pleaded guilty to the charge brought by the Health and Safety Executive (HSE).

The Birmingham Ash

Judge Richard Wakerley QC said: "The condition and the danger the tree presented would have been obvious to anyone making a close inspection of that tree."

Influencing cases

• POLL vs. VISCOUNT ASQUITH of MORLEY

• (POLL V BATHOLOMEW)• An accident involving a motorcyclist

colliding with a fallen tree in July 2001• Judgement in May 2006 in favour of

claimant• Focus on competence by experts• Levels of Inspection• Foreseeability

20072006

National Tree Safety Group(NTSG)• Group first met in 2006 – convened by Sir Harry

Studholme, Forestry Commissioner• Formally launched January 2007• Commissioned 3-part research from DARM

(Centre for Decision Analysis and Risk Management): 1. Quantify risk to public health from falling trees 2. Perceived risk and public concern3. Evaluation of future control measures

• Legal advice to establish duties and responsibilities in relation to tree risk management

• National Conference May 2008

NATIONAL TREE SAFETY GROUP

TREE MANAGEMENT

FOR

PUBLIC SAFETYTowards an Industry

Statement A ONE-DAY CONFERENCE

29th May 2008

270 attended

NTSG Management group

• Chair: Judith Webb, Forestry Commissioner• Ancient Tree Forum• Arboricultural Association• Confederation of Forest Industries• Country Land and Business Association (and NFU)• Forestry Commission• Institute of Chartered Foresters• London Tree Officers Association• National Trust• Royal Institution of Chartered Surveyors• Tree Council• Woodland Trust • Observer: British Standards Institution

To develop a nationally recognised approach to tree safety management.

To provide guidance that is proportionate to the risks posed by trees.

NTSG Objectives

To work transparently and inclusively with as wide a stakeholder group as possible.

To provide guidance that is strategic, rather than prescriptive, and authoritative.

Who is the guidance for?

Anyone responsible for managing tree safety, or governing it:Individual householder with trees Small businessFarm / EstateGolf course / Caravan parkLocal Authority – urban / ruralMajor land owners / tree managers / Utility managersRegulatorsLaw courts

What do we know?

The overall risk of harm to the general public from falling trees or parts of trees is extremely low.

We already manage trees extensively for both their health and our safety (and network resilience).

In recent years there has been an increase in the ‘defensive’ felling of trees for fear of litigation.

What do we know?

• It is clearly unreasonable and impracticable to inspect all trees, regardless of their position

• Trees provide a wide range of benefits to the whole of society but responsibility (duty of care) rests with the owner / manager

• Tree owner /managers (duty holders) are in the best position to understand what trees they have and the context of those trees

NTSG Principles

• Trees are good • Living natural organisms – bits naturally fall off• The overall risk to human safety is extremely

low• There is a legal duty of care for safety• A balanced approach - reasonable and

proportionate• Strategic guidance

The HSE’s Tolerability of Risk Framework

(Threshold risk level: 1 in 1 million)

Where does tree-related deathlie on the ToR framework?Part 1 of the DARM research shows that there were 64 fatalities to the public during the ten years from 1 Jan 1999.

The mean annual fatality rate in the UK is therefore 6.4.

The population exposed is 60 million.

Therefore the overall risk to individuals is about 1 in 10 million or less per annum.

Tree risk in perspective

Overall risk v individual risk

• Of course, some individual trees will pose a higher risk than 1 in 10 million, while others pose a lower risk

• The trick is to find the very few trees that may cause damage or injury before they find us, by applying sensible risk management

• Some ‘target areas’ by their nature, represent a different level of risk

Power lines present a different level of risk

Railways present a different level of risk

Photo courtesy Network Rail

(De-railed train in distance)

Photo courtesy Network Rail

Do trees generate ‘societal risk’or ‘societal concern’?

The HSE states in its SIM:

“... However, the low level of overall risk may not be perceived in this way by the public, particularly following an incident.”

DARM part 2 research

Prof. David Ball explored the public perception in relation to harm from falling trees, in comparison to other known causes of concern.

He studied governmental policy and other existing research in this area.

He identified that perception of risk must always be viewed in relation to the benefit derived.

.Falling trees

27

Public desire for extra control

.

DARM conclusion

The conclusion is that there are no grounds for any other approach to tree safety management than the application of rational, cost-effective measures.

In the public interest, measures which are not shown to be rational or cost-effective should not be implemented.

29

The risk-benefit trade-off

Risk of harm Benefit of thing or activity

Challenges

• How to make a risk-benefit assessment?• Conventional HSE calculation of risk v cost of

risk reduction does not recognise the resultant reduction of benefit – to individuals and the whole of society

• Risk reduction v benefit reduction - i.e. Assessment in context of benefit

• Further discussion with HSE is on-going

NTSG Outcomes

• Position Statement• NTSG inclusive – open membership

• Tree risk management - proportionate to real risks

• Evidence based

• Balance between Risks and Benefits

• Risk benefit trade off

• Calculation – contextual – duty holder decision maker

• Take account of role and contribution of trees

• Large organisations – formal policy

• Reasonable - Non-defensive

NTSG Outcomes

Guidance at three levels:1. Information leaflet or ‘briefing note’ – a small

(4 sides of A4) leaflet summarising the principles.

2. Concise guidance document (8-12 pages) - providing full detail of the principles and how they might be applied in a number of case studies.

3. The full guidance document, printed hard copy and/or web-based, including appendices of research and background information.

Why read this leaflet? To help you understand the issues around tree safety and come to a balanced conclusion: one that ensures that trees, essential for the ecosystem and common good, can thrive in the UK, uncompromised by unnecessary safety management.

NATIONAL TREE SAFETY GROUP

Managingtreesfor safety

If you own a tree, then you need to read this leaflet…

N T S G

NTSG Full Guidance

• Discusses the many benefits that trees bring to society

• Considers the risks from falling trees, within the wider context of other risks

• Outlines the legal framework for considering trees in relation to public safety

• Seeks to provide reasonable and practical measures to fulfil legal responsibilities

• Provides several scenarios as models for putting these measures into practice.

NTSG Full Guidance

Content of the main guidance document reflects NTSG principles:• Trees are good • Living natural organisms – bits naturally fall off• The overall risk to human safety is extremely low• There is a legal duty of care for safety• A balanced approach - reasonable and proportionate• What you should do

When will the Guidance be available?

Possible publication – July / August 2011

Thank youThank you

Practical Guidance

• Key Issues:• Duty holder’s management strategy• Which trees to inspect• Level of inspection – who should

inspect?• Frequency of inspection

‘Work in progress’ Diagram courtesy Jeremy Barrell

‘Work in progress’ Diagram courtesy Jeremy Barrell