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BS 3998 2008 Recommendations for tree work 3 Terms and definitions For the purposes of this British Standard the following terms and definitions apply WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008 6 3 1 competent person person e g an arboriculturist who has training and experience relevant to the matter
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A link to the BSI British Standards Draft Review system or to a specific draft hosted on the system may be. distributed to other interested parties so that they may register and submit comments It is not necessary to. purchase a copy of the draft in order to review or comment on it however additional copies of this draft may be. purchased from BSI Tel 44 0 20 8996 9001 or email cservices bsigroup com Drafts and standards are also. available in PDF format for immediate download from the BSI Shop http www bsigroup com Shop. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A BRITISH. STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. DRAFT BS 8516 2008,BRITISH STANDARD,Recommendations for tree. safety inspection,ICS x xxx xx, NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A BRITISH. STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. BS 8216 2008,Publishing and copyright information, The BSI copyright notice displayed in this document indicates when the document. was last issued,ISBN 978 0 580 XXXXX X, The following BSI references relate to the work on this standard. Committee reference B 213,Draft for comment 08 30174363 DC. Publication history,First published xxxxxxx 2008,Amendments issued since publication. Amd No Date Text affected, WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. Introduction 5,2 Normative references 5,3 Terms and definitions 5. 4 Factors to consider 8,5 Legal and related considerations 10. 6 Quantifying the risk from hazard trees 10,7 Frequency of inspections 11. 8 Remedial action 11, Annex A informative Legal and related considerations 12. Annex B informative Government circular 15,Annex C informative Government circular 15. Bibliography 18, WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. Publishing information, This British Standard is published by BSI and came into effect on XX Month 200X It. was prepared by Technical Committee B 213 Trees A list of organizations. represented on this committee can be obtained on request to its secretary. Information about this document, This is a new British Standard that has been prepared in order to provide authoritative. recommendations and guidance on tree inspection for health and safety purposes. Use of this document, As a code of practice this British Standard takes the form of guidance and. recommendations It should not be quoted as if it were a specification and particular. care should be taken to ensure that claims of compliance are not misleading. Any user claiming compliance with this British Standard is expected to be able to. justify any course of action that deviates from its recommendations. It has been assumed in the preparation of this British Standard that the execution of its. provisions will be entrusted to appropriately qualified and experienced people for. whose use it has been produced,Presentational conventions. The provisions in this standard are presented in roman i e upright type Its. recommendations are expressed in sentences in which the principal auxiliary verb is. Commentary explanation and general informative material is presented in smaller. italic type and does not constitute a normative element. Contractual and legal considerations, This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application, Compliance with a British Standard cannot confer immunity from legal. obligations, WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. Introduction, Trees are dynamic living organisms capable of achieving considerable size and. structural complexity The laws and forces of nature dictate a natural failure rate even. among intact trees by their very nature trees cannot be considered entirely free of. risk though this is generally present at very low and acceptable levels. Trees are exposed to and can become damaged by the elements and have co evolved. with pathogens that can degrade and sometimes destroy their structural integrity Due. to genetic characteristics and local microenvironmental factors this integrity may be. innately uncertain, Where trees grow in areas of public access or within falling distance of man made. structures collectively termed targets branch shedding or whole tree failure can. potentially cause severe harm including loss of life. Owners or occupiers of land have a duty of care see Annex A that could have. implications for tree management including proactive inspection and maintenance. It is important that people having or taking ownership of or responsibility for trees. collectively termed tree owners are aware of their condition Tree inspection. see Clause 4 and Clause 7 provides relevant information to inform management. decisions and demonstrates that care has been taken This will be enhanced by. carrying out any recommended actions see BS 3998 2008. The inherent risks associated with trees mean that it is a mistake to manage them in an. overly risk averse manner In addition to considerations of tree safety it is important. that management decisions are taken in light of their wider benefits aesthetic. ecological environmental and sociological Management decisions to address. identified hazards that exceed what is necessary to the detriment of these benefits are. inappropriate, Finally attractive and or notable trees can be severely damaged by structural failure. so as to threaten their viable retention in such cases expert inspection to identify tree. work to prevent major collapse can be justified on purely arboricultural grounds. This British Standard addresses considerations arising from the need to inspect trees. in order to assess and if necessary reduce their potential for structural failure. This standard does not apply to other risks associated with trees such as obstruction. of highway visibility slip and trip hazards and tree root damage to buildings. It is aimed at tree owners and managers and at all those designing tree inspection. regimes and undertaking tree inspections,2 Normative references. The following referenced documents are indispensable for the application of this. document For dated references only the edition cited applies For undated references. the latest edition of the referenced document including any amendments applies. BS 3998 2008 Recommendations for tree work,3 Terms and definitions. For the purposes of this British Standard the following terms and definitions apply. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. competent person, person e g an arboriculturist who has training and experience relevant to the matter. being addressed and can demonstrate competence to undertake systematic expert tree. inspection in order to identify and recommend remediation for hazards arising from. impaired structural integrity in trees, enzymatic alteration of wood by specialized fungi leading to a biodegradation of the. load bearing properties of affected trees and their constituent parts. decay mapping, examination by invasive or non invasive means of the internal tissues of a tree. including above and below ground parts, NOTE Used to determine the extent and significance of decay initially identified by visual tree. assessment VTA, source or situation with a potential for harm in terms of death ill health or injury or a. combination of these,BS 8800 2004 2 5, NOTE Tree inspection is a process of hazard identification. hazard tree, tree in such a condition that structural failure is expected with the potential to result in. harm to persons or property see 3 9, NOTE Trees can have wholly internalized structural weaknesses including decay which are not. apparent on visual inspection such that their failure should this occur is not reasonably foreseeable. combination of the likelihood and consequence s of a specified hazardous event. BS 8800 2004 2 16,risk assessment, process of identifying hazards and evaluating the risks to health and safety arising. from these hazards taking account of the existing risk controls or in the case of a. new activity the proposed risk controls,BS 8800 2004 2 17. risk control, selection and application of suitable measures to reduce risk. BS 8800 2004 2 18, persons or objects the latter having variable value and vulnerability present perhaps. temporarily within falling distance or impact radius of a tree or its branches. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. tree inspection, visual assessment to determine various attributes of trees as determined by the level of. arboricultural knowledge of the person concerned, NOTE Different levels of inspection are defined in 3 10 1 to 3 10 4. rudimentary inspection by untrained persons e g owners of trees at private. residential addresses that might identify very obvious potential hazards and or. significant change so as to prompt where appropriate an inspection by a competent. NOTE Very obvious potential hazards and or significant change include to their growing environment. e g loss of an adjacent tree formerly providing shelter presence of fungal fruiting bodies e g. brackets and toadstools large dead branches broken or storm damaged parts and partial uprooting. including root damage resulting from adjacent excavation. preliminary but systematic inspection undertaken possibly using binoculars mallet. and probe by a person trained to observe obvious potential hazards e g tree warden. park ranger or highway safety inspector so as to inform where appropriate a risk. control decision including inspection by an expert. NOTE Obvious potential hazards include altered exposure large dead branches crown decline. exudates on trunks presence of fungal structures cankerous lesions cavities compression forks. cracks splits dead peeling bark injury including lightning strike wilting thinning of foliage and. severed roots including root damage resulting from adjacent excavation. systematic and diagnostic process of visual inspection by a competent person e g an. arboriculturist from ground level using binoculars mallet and probe as necessary in. order to gain sufficient understanding of a tree s structural condition so as to inform. where appropriate reinspection interval and management recommendations risk. control measures including detailed inspection see 3 10 4. specialized examination identified as being necessary during expert inspection by a. competent person e g an arboriculturist variously comprising aerial access to view. upper parts of the tree or the use of specialized e g decay mapping equipment. NOTE 1 Those undertaking basic expert and detailed inspection need to have professional indemnity. NOTE 2 The practice of inspecting trees in the United States from a moving vehicle with two people. one driving one inspecting known as windshield inspection has proved an efficient and. economical way to cover many miles of tree lined roads However the practicalities are greatly. reduced when carried out in an urban environment Research of the efficacy of this approach has. demonstrated an 89 correlation of hazard assessment given to trees based on defects found when the. same trees were subsequently assessed by an inspector on foot 1. Research carried out by Christopher Rooney a Graduate student of University of Massachusetts and reported at. the ISA conference in Montreal in August 2003, WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. visual tree assessment VTA 1, method of tree inspection used by arboriculturists to evaluate the structural integrity. of a tree relying on observation of biomechanical and biological features including. decay and fungal structures,4 Factors to consider,4 1 Timing of inspections. COMMENTARY ON 4 1, Due to the reliance of expert inspection on visually apparent symptoms as diagnostic aids inspections. undertaken at differing times of the year present a variety of benefits and obstacles For example. inspecting a tree in full leaf assists in determining physiological condition from foliage quality but is. hindered by leaves obscuring the tree s structure Conversely inspecting a deciduous tree in bare. branch condition allows a good view of the structure but no assessment of foliage. Successive expert inspections should where practicable be undertaken at differing. times of year unless there are indications to the contrary see Clause 7 as this. facilitates inspection under a range of conditions albeit over time. NOTE It is important that inspection regimes are implemented and reviewed and that records are. maintained,4 2 Prioritising inspections,COMMENTARY ON 4 2. People or organisations with responsibility for large numbers of trees might need to prioritize their. inspections however this does not negate the recommendation for quinquennial inspection. see Clause 7, A prioritized inspection schedule should be undertaken based on levels of access i e. exposure of people to hazard and arboricultural advice taking account of relevant. factors where known that affect safety such as the age class condition size and. species of the trees, Where exposure increases for example an outdoor concert held in a normally. unoccupied park the inspection regime should respond to the changed demands of the. site usage to ensure that appropriate and effective risk controls are provided. see Clause 6 and Clause 8 BS 8800 2004 3 5 3 states in part. A risk assessment should always be carried out and the control measures. implemented before changes are made to work activities or before new activities. 4 3 Data recording,4 3 1 General, The data to be recorded varies with the level of inspection and should reflect the. Lay and basic inspections need not be as exhaustive as expert inspections though any. observations giving rise to concern over tree safety should be recorded together with. the date and referred for expert inspection in a timely manner i e as soon as can. reasonably be arranged,4 3 2 Basic inspection, Those undertaking or managing basic inspections should retain a written record of. a date of inspection, WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. b name of person undertaking the inspection, c trees inspected listed by common name or identification number referenced to a. tree tag or a plan and or the specific location or area zone in which trees were. d any obvious hazards observed, e any limitations preventing inspection to the required level. f species listed by common name and location or identification number of the. hazard trees concerned, g action taken including referring the trees concerned for timely expert inspection. 4 3 3 Expert inspection, For expert inspection the minimum data recorded and retained should be. a date of inspection,b name of person undertaking the inspection. c trees inspected or the specific area zone in which trees were inspected. d identification and location of individual hazard trees. e species by common and scientific name,f age class. g significant defects present assessed as being hazardous. h any limitations preventing systematic inspection. i recommended actions if required, j timescale for implementing the recommendations based on the risk posed. k interval to and preferred time of year for the next expert inspection. NOTE 1 Optional data could include for example tree dimensions. NOTE 2 Trees not found to have significant defects and or not directly threatening an identified. target need not be recorded during the inspection 2 providing that the date of inspection and the. area inspected are recorded it can be assumed by implication that all trees present within the area. have been inspected This may be appropriate particularly where large numbers of trees are involved. and the practicalities of identifying each tree are unrealistic and uneconomical. Recommendations for risk control measures see Clause 8 should be reported to the. level of management or person with the authority to initiate the necessary action. 4 4 Climatic considerations,COMMENTARY ON 4 4, Severe weather conditions can damage and so weaken the structure of trees causing primary failure. thereby predisposing them to secondary failure i e collapse. Example conditions include, strong winds especially of Force 8 or greater particularly from atypical directions. heavy rain reducing root adhesion due to soil saturation. heavy snowfall leading to branch failure, Consideration should be given to implementing at least basic inspections in the. aftermath of storm events especially for trees previously identified as being. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. particularly vulnerable and or for those standing adjacent to high value targets e g. trunk roads, Trees known to have been struck by lightning should be inspected as soon as is. practicable thereafter,4 5 Ivy and other climbing plants. Ivy and other climbing plants can obscure the structure of a tree preventing thorough. inspection The target and risk should determine the need for inspection via aerial. access climbing inspection or inspection from a hydraulic work platform or the. removal of the plants concerned prior to inspection. Ivy and other climbing plants can provide a valuable wildlife habitat and may harbour. protected species attention is drawn to relevant legislation summarized in Tree. Damage Alert No 123 3 Such plants should therefore only be removed where. this is essential to allow thorough inspection usually at expert level. 5 Legal and related considerations, The following documents should be considered when planning and or undertaking. tree inspections, Government Circular 90 73 reproduced in part in Annex B Inspection. Maintenance and Planting of Roadside Trees, Government Circular Roads 52 75 reproduced in full in Annex C Inspection. of Highway Trees, NOTE 1 See also the Network Maintenance Manual Highways Agency 2007 4 and Well. Maintained Highways Code of Practice for Highway Maintenance Management Department for. Transport 2005 5 see Annex A, NOTE 2 See Annex A to Annex C for detailed information on legal considerations including statutes. and case law,6 Quantifying the risk from hazard trees. Where consideration is being given to the retention of a hazard tree in identifiably. poor structural condition a detailed assessment should be undertaken to quantify the. associated risk and a written record retained, NOTE Such quantified risk assessments can also be employed in other cases. Where tree risk is to be quantified the following factors should be considered. a likelihood that an identified defect including decay will lead to structural failure. b nature of the target see also 4 2, c consequences for the target concerned of an impact from the defective part i e. scale of impact relative to durability of target, These three factors should be systematically assessed and considered in combination. in order to determine the risk posed by the tree concerned and to confirm its. suitability for retention including where this is only acceptable through. implementation of risk control measures see Clause 8. NOTE Various proprietary methods are available for use by arboriculturists in analysing the inter. relationships of the factors referred to above Whilst such methods can assist in managing hazard. trees the judgement of a competent person e g an arboriculturist remains the most reliable. analytical tool, WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. 7 Frequency of inspections,7 1 Lay inspection, It is generally accepted that layman tree owners should be familiar with the condition. of their trees most suitably facilitated by regular observation and or annual. inspection,7 2 Basic inspection, In the case of basic tree inspection the interval between inspections should be driven. by site usage though annual inspection is usually appropriate for targets such as well. used highways, NOTE A two to three year cycle may be appropriate for less frequented sites. 7 3 Expert inspection, The maximum interval between expert inspections where a target is or foreseeably. may be present should be five years, NOTE Departure from this recommendation may be justified where there is identifiably infrequent. access recorded as such at a strategic level, Within this maximum parameter the interval between systematic expert inspections. should be varied in order to take account of a tree s condition and context including. site usage and changes in circumstances and growing conditions The interval should. also take account of the findings of each previous expert inspection and those of any. lesser inspections undertaken in the meantime, The precise timing of inspections should reflect the nature of any defects known to be. present e g seasonally occurring fungal structures see also 4 1 and should also. address where possible any limitations that formerly reduced the effectiveness of a. prior inspection e g dense foliage see also 4 5, The competent person e g arboriculturist undertaking an expert inspection should. identify the appropriate interval to and preferred time of year for the next scheduled. expert inspection,8 Remedial action, 8 1 Target management non arboricultural intervention. Where defects are identified that are assessed as posing an unacceptable risk thereby. requiring risk control measures consideration should firstly be given to modifying the. target including, a exclusion e g erection of barriers or establishment of deterrent plants such as. blackthorn, b diversion e g re routing paths away from the tree. c relocation e g moving benches from under the canopy spread. 8 2 Tree work arboricultural intervention, Due to the various benefits conferred by trees including habitats protected by law. risk control measures should be directed specifically at remediating the identified. potential hazards For example a large dead branch identified as hazardous but also. having habitat value should be considered for partial retention by truncation rather. than complete removal see BS 3998 2008 para, NOTE Options for arboricultural intervention are set out in BS 3998 2008. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. Annex A informative,Legal and related considerations. A 1 Statutes,A 1 1 The Occupiers Liability Act 1957 1984 6. Section 1 1 of the 1957 Act and section 1 1 a of the 1984 Act define the scope of. the Acts in regulating the duty which an occupier of premises owes in respect of. dangers due to the state of the premises or things done or omitted to be done on. The 1984 Act extended the scope of duty of care to others i e those present on land. uninvited though three additional criteria need to be met before any duty is owed. These criteria are set out at section 1 3 of the 1984 Act. An occupier of premises owes a duty to another not being his visitor in respect of. any such risk as is referred to in subsection 1 above if a he is aware of the danger. or has reasonable grounds to believe that it exists b he knows or has reasonable. grounds to believe that the other is in the vicinity of the danger concerned or that he. may come into the vicinity of the danger in either case whether he has lawful. authority for being in that vicinity or not and c the risk is one against which in all. the circumstances of the case he may reasonably be expected to offer the other some. protection, The duty under both Acts applies to those who occupy the land i e those who have a. sufficient degree of control over it such that they ought to realize that any failure on. their part could result in injury to those visiting whether invited or not or passing by. Two or more parties can simultaneously be occupiers each with the same duty. towards visitors passers by, The duty should be thought of as a requirement to take what care is reasonable under. all the circumstances to ensure that the visitor passer by is reasonably safe This. includes a consideration of the circumstances of the occupier s and the reasonable. availability of measures to prevent injury, A 1 2 The Health and Safety at Work etc Act 1974 7. This Act requires that risks to employees and also third parties be reduced so far as is. reasonably practicable Section 3 of this Act has been used by the Health and Safety. Executive to prosecute a local authority following fatalities arising from tree failure. Section 3 1 states, It shall be the duty of every employer to conduct his undertaking in such a way as to. ensure so far as is reasonably practicable that persons not in his employment who. may be affected thereby are not thereby exposed to risks to their health or safety. A 1 3 The Local Government Miscellaneous Provisions Act 1976 8. Section 23 of this Act provides local authorities with the power to make safe. imminently dangerous trees on land under third party ownership The power extends. to a recovery of any costs incurred by the authority in exercising the power. A 1 4 Highways Act 1980 9, Section 130 confers on highway authorities a duty in law to prevent as far as. possible the stopping up or obstruction of highways. WARNING THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A. BRITISH STANDARD THIS DRAFT IS NOT CURRENT BEYOND 31 JULY 2008. Section 154 of this Act provides highway authorities with the power to require any. vegetation that threatens the safe use of any highway or other road or footpath to. which the public have access to be cut or felled within 14 days The power under. section 154 1 relates to danger obstruction and interference with the operation. of the highway including endangerment impeding passage of vehicles horseriders. and pedestrians and restrictions of visibility, Section 154 2 of the Highways Act 1980 is designed to address dangers arising from. hedges trees and shrubs that are dead diseased damaged or insecurely rooted such. that the whole or a part is likely to cause a danger by falling on the highway road or. A 2 Non statutory guidance, The Network Maintenance Manual Highways Agency 2007 4 states in Woodlands. Trees and Hedgerows paragraph 3 13 3, Management of trees woodlands and hedgerows must be planned to ensure these. elements fulfil their objectives and functions as defined in the DMRB Volume 10. Section 0 and as set out in the appropriate landscape management plan. Trees are an important amenity feature of the roadside soft estate and their. contribution to the environment is such that they must be retained wherever it is safe. to do so Highway trees do however have the potential to pose a threat to the safety of. road users pedestrians and to adjoining property and livestock Any external signs of. decay or deterioration must be reported by the inspector for action by a qualified. arboriculturist, Trees that lie within falling distance of the highway boundary but located outside the. highway boundary and not in the ownership of the Service Manager are classified as. highway trees as described in Section 154 Highways Act 1980 If such trees are. found to be in an unsafe condition the Service Manager has the power to order the. owner to carry out such work as may be necessary to make the tree safe If this is not. carried out by the owner within 14 days the Service Manager has the power in. accord with the provisions of Section 154 of the 1980 Highways Act to carry out the. work and recharge the cost of the work to the owner. However trees beyond the highway boundary may be subject to tree preservation. orders TPO In these situations The Highways Act 1980 may not apply and planning. permission may need to be sought to remove the tree discussion with the appropriate. Local Authority Tree Officer must be undertaken, Qualified arboriculturists must be employed by the Service Provider to carry out. specialist inspections and to advise on signs of ill health or damage to trees Care must. be taken to ensure the appropriate maintenance of veteran trees trees that are of. interest biologically aesthetically or culturally because of their age. A 3 Case law,Attention is drawn to the following case law. Shirvell v Hackwood Estates Co Ltd 1938 2 K B 577, It was held that the owner of a tree standing in a remote location where no public. access could reasonably have been foreseen was not liable for the death of a person.