Download pdf - Arboriculture Report and Impact Assessment · Countryside Act 1981 (schedule 5) and included in schedule 2 of the Conservation Regulations 1994. Ideally, a survey should be carried

Land Adjacent to Meadow Avenue, Bacup OL13 8DF January 2013

Birtle Tree Services Ltd

Tree Services and Consultants

Penn Green House, Birtle Road, Birtle, Bury, Lancashire BL9 6US Telephone 0161 272 0009 [email protected] www. birtletreeservices.co.uk

Arboriculture Report and Impact Assessment

For proposed development at

Land Adjacent to Meadow Avenue, Bacup OL13 8DF

Produced by

Hilary Birtwistle, FdSc (Arb), TechArbor A

of


On the instruction of

Mr E McGuiness

January 2013


Contents

1 Introduction 1

1.1 Instruction and references 1

1.2 Scope and limitations of the report 1

2 Site Visit 2

2.1 Weather Conditions 2

2.2 Topography and Surfaces 2

3 Statutory Control and Protection in Respect of Trees and Associated Wildlife 2

3.1 Standard of Work 2

3.2 Tree Preservation Orders, Conservation Area Designations and

Issues of Tree Ownership 3

3.3 Wildlife 3

4 Tree Survey 3

4.1 Tree Survey and Data Collection 3

5 Proposed Development, Impact Assessment and Mitigation Proposals 5

5.1 Scope and Limitations of Arboricultural Impact Assessment 5

5.2 Impact Assessment Data 5

5.3 Root Protection Area and Construction Exclusion Zone 7

5.4 Protective Fencing 7

5.5 Specification for protection to trees during installation of utilities 7

5.6 Constraints within the Root Protection Area 8

6 Tree Protection Plan and Arboricultural Method Statement 9

6.1 Tree Protection Plan 9

6.2 Arboricultural Method Statement 9

6.3 Specification for the protection of T1, T2 and T3 9

6.4 Additional Precautions Outside Fenced Areas 11

7 Soil Survey and British Geographical Society Survey 11


Appendix 1 Approximate location of development site

Appendix 2 Image of T1, T2 and T3

Appendix 3 Tree Protection Plan

Appendix 4 Tree Survey Data Explanatory Notes

Appendix 5 Scaffolding within Root Protection Area with Protective Fencing

Appendix 6 No dig driveway and parking surfaces

Appendix 7 British Geological Society – Natural Subsidence Report


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1 Introduction

1.1 Instruction and references

The site consists of a derelict land that has in the past been a coal yard. The site is located on the

corner of Meadow Avenue and Burnley Road, Bacup. The development proposal is to erect 6 semi-

detached residential properties. Prior to submission for outline planning permission, the local

authority planning department have requested an arboricultural survey to be undertaken and

report to be provided in relation to the poplar tree (T1) that is located on the boundary of the

development site and the adjacent property, 8-10 Gordon Street, with particular reference to the

steps to be taken to protect the roots of the tree during planning and construction by means of the

identification of the Root Protection Area, undertaking an impact assessment and providing

guidance regarding the controls that are to be put in place during development. Whilst the

planning department have only requested that the poplar tree be included within the report, the

root protection area of two other trees (T2 and T3) are included within this report as their roots

require similar protection.

Mr E McGuiness, joint owner of the land, has instructed Birtle Tree Services Ltd to undertake an

arboricultural report including an impact assessment and tree protection plan to ensure the trees

are sufficiently protected during the construction of the extension.

1.2 Scope and limitations of the report

The purpose of the report is, having carried out a visit to the development site to survey the tree

(T1) which is located to the south of the site, to ascertain whether it will be affected by the

proposed development in accordance with BS 5837:2012 Trees in relation to design, demolition and

construction – Recommendations

The two other trees which are of significant size (T2 and T3) have been included in terms of their

root protection area but as the planning department had not included these trees in their request

for an arboricultural report a full survey has not been undertaken and is not deemed to be

necessary,

Further, the purpose of the report is to identify the impact of the development on the trees and

provide guidance to minimise and mitigate any adverse impact.

The report is based upon a visual inspection from ground level and no climbing has been

undertaken to gather evidence. The consultant shall not be responsible for events that happen

after the date of the report due to factors that were not apparent at the time, and the acceptance

of this report constitutes an agreement with the guidelines and the terms listed in this report.

Any defects seen by a contractor, agent or the owner that were not apparent to the consultant

must be brought to the consultant’s attention immediately.

The consultant accepts no liability in respect of the trees unless the recommendations of this

report are carried out under his/her responsibility.

The potential influence of trees upon buildings or other structures resulting from the effects of

their roots abstracting water from shrinkable load-bearing soils is not considered herein. The


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advice of a structural engineer should be sought with regard to appropriate foundation depths for

new buildings with reference to NHBC Standards Chapter 2.3 (NHBC, 2008).

The tree that has been surveyed does not appear to be potentially hazardous however this report

should not be seen as a substitute for a full tree risk assessment or management plan which are

specifically designed to minimise risk and liability associated with responsibility for trees.

The Tree Protection Area which is shown in the Tree Protection Plan (Appendix 3) is an estimation

and is not intended to replace development plans. Scaling and measurements, whilst being a close

approximation, should not be relied upon for construction purposes.

The limitations of this report are restricted to the persons, time, information made available and

purpose for which this report has been prepared.

Please note that all trees are at risk of failure through exceptional weather conditions.

2 Site Visit

2.1 Weather Conditions

Hilary Birtwistle carried out the survey and assessment of the trees 4th January 2013.

The weather conditions at this time were poor with medium rainfall and heavy rainfall had been

experienced in the region for a prolonged period of time. Visibility was not impaired. The survey is

limited to the area shown in Appendix 1.

2.2 Topography and surfaces

The area slopes upwards from west to east with a culvert at the western edge. The site has

previously been a coal yard but is now disused and overgrown although there is little evidence of

the area being colonised by self seeding native trees or by invasive weeds such as Himalayan

Balsam.

The south of the site is very water logged with standing water. There has been very high regional

rainfall over the previous months and the area is evidently beyond field capacity with obvious

drainage issues in this area. The north, east and west of the site whilst the soil is at field capacity

does not show the same level of water logging.

The trees are located along the southern boundary of the site and are raised approximately 1

meter above the level of the development site.

The trees are surrounded by lawned and overgrown garden to the west, south and east.

3 Statutory Control and Protection in Respect of Trees and Associated Wildlife

3.1 Standard of Work

Any tree work undertaken should be in accordance with British Standard 3998: 2010 and by

competent arboriculture contractors with public liability insurance cover of at least two million

pounds or competent local authority employed arborist.


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3.2 Tree Preservation Orders, Conservation Area Designations and Issues of Tree

Ownership

A check needs to be undertaken with the local authority to ascertain whether the trees are subject

to a Tree Preservation Order. If so any and all works undertaken must have the written consent of

the local authority prior to work commencing.

Desk research has indicated that the area is not within a designated Conservation Area however it

is recommended that any work that may be undertaken to the trees should be approved by the

tree owners prior to works being undertaken. Whilst the legal position relating to branches over

hanging means that permission is not required for the removal of branches that are overhanging

the boundary fence line and the development site owner is at liberty to remove the branches as

long as they are offered to the tree owner. In order to maintain good relationships with the tree

owners’ discussion with them prior to work being undertaken is highly recommended.

3.3 Wildlife

All operations should take account of wildlife needs and be planned to take advantage of weather

conditions and time of year for minimum damage and disturbance. If any protected species of

nesting birds are present or discovered while the works are taking place all work should cease until

contact has been made with English Nature for further advice. English Nature can be contacted on

01942 820342 or by e-mail to: [email protected] Specific consideration should be

given to the possible presence of roosting bats, which are protected by the Wildlife and

Countryside Act 1981 (schedule 5) and included in schedule 2 of the Conservation Regulations

1994. Ideally, a survey should be carried out to identify any potential roost sites and if bats are

found to be present advice should be sought from a person qualified and experienced in handling

such matters and fully conversant with the implications of the Act. There is no evidence that the

trees are used as a roosting site for bats. There is no evidence of nesting birds however the best

time to undertake any works would be during autumn, winter or before the nesting season begins

in the spring.

4 Tree Survey

4.1 Tree Survey and Data Collection

The following table should be read in conjunction with Appendix 4 (Tree Survey Data Explanatory

Notes) in order to correctly interpret the tree data.

mailto:[email protected]


Page 4

Table 1 Tree Survey Data

Ref

Age and Species

Height (m)

DBH

Approximate Crown

Spread (m)

N W E

S

Notes

Recommendations

Vigor Amenity Value

Crown Clearance (m)

N W E

S

Physiological Condition

Life Expectancy

(yrs)

Priority Inspect Freq (yrs)

Structural Condition

Retention Category

T1 Poplar

Populus nigra

26 84 9.0

4.5 4.0

6.0

W

2.5

S W

4.7 2.5

T1 is located to the south of the development site and is raised approximately 1 metre from the development site ground level. There is little evidence of deadwood within the canopy and there is no evidence of poor pruning or natural shedding which has left pegs. Therefore there is no requirement for the any pruning or maintenance interventions. There is no evidence of decay or presence of fungal fruiting bodies on the tree or on the ground close to the tree. The area to the north of the tree is waterlogged which has the potential to impact on the roots as such conditions produce an environment that is detrimental to the trees growing needs as the soil becomes anaerobic. There is no evidence that the tree is under stress due to these conditions at the present time and poplars have a natural tolerance to wetter conditions however the tree should be re-inspected with due consideration given to the ground conditions and any adverse impact this may have. The prevailing weather conditions will undoubtedly have influenced the amount of surface water present and this may be a temporary problem which re-inspection may well confirm.

The tree is in good condition and at the present time requires no maintenance of management works. Crown lifting to the north of the tree is required to achieve a 5metre clearance to ensure equipment and plant can operate without damaging the tree

Moderate

Good

Good

High

<40

A2

2.5 5.0 6.0

3.5

Low and dependant on when the

development begins

3 yrs


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5 Proposed Development, Impact Assessment and Mitigation Proposals

5.1 Scope and Limitations of Arboricultural Impact Assess ment

The purpose of this section of the report is to:

a) Assess the implications, if any, that the proposed development will have on the trees

surveyed on 4th January 2013 carried out by Birtle Tree Services Ltd.

b) Advise on arboricultural measures which would be necessary to protect the tree

including it’s’ roots.

The limitations of this report are restricted to the persons, time and information made available and

purpose for which the report has been prepared.

5.2 Impact Assessment Data

The Tree Protection Plan (Appendix 3) identifies the location of the trees in relation to the proposed

development site.

The local authority has requested that an arboricultural report be completed in relation to T1.

However, whilst T1 has been subject to full survey, T2 and T3 have been included in the impact

assessment as it is considered that the protection of their roots is also required.

The table below indicates the impact of the trees on the development site.

The Impact Table details the Root Protection Area (RPA) in accordance with the British Standard

5837:2012 Trees in relation to design, demolition and construction – Recommendations. This is an

area that should be left undisturbed in order to provide adequate rooting area for the trees.


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Tree No.

Root Protection Area

Implications and mitigation

T1 319 m2 = circle with a radius of 10m

A variety of development designs have been considered however the Root Protection Area (RPA) will determine the ultimate proximity of the houses to the southern boundary of the site. Within the RPA construction opportunities are limited however landscaping can take place (see section 6.3 regarding mitigation to minimise impact on the roots), hard standing for car parking is a further possibility using a cellular confinement system (see appendix 6 regarding the specification) BS5837 supports the view that a tree will compensate for a limited amount of its root area being covered by impermeable materials however this very much depends on the age of the tree, its overall health and vigour, and its ability to withstand the stress of its growing environment being impacted upon. Whilst T1 is a health and vigorous specimen, as an early mature tree of significant size, it is proposed that a design solution is reached that does not require the construction of houses to encroach into the RPA The crown clearance is not sufficient to allow plant and machinery to operate without risk of damage to branches and for this reason crown lift is recommended to achieve a clearance on the northern side of 5 metres. Consideration must be given to the implications relate to the protection of the tree roots in terms of potential compaction of the soil, potential siting of services and storage of materials a safe distance from the Root Protection Area. Work methods will need to be adopted to ensure the Root Protection Area is maintained and protective fencing must be erected prior to any and all works beginning. It is recommended that construction should not be undertaken within the RPA however guidance is provided in section 5.5 and appendix 5 relating to location of services and use of scaffolding within the RPA should that be necessary.

T2 132 m2 = circle with a radius of 6.5m

The protective fencing is to be erected prior to works starting and to be located to cover crown spread which will remove the need for crown lifting as the crown will be protected from plant and machinery. Consideration to be given to storage of materials, compaction of soils and maintenance of soil levels within the RPA.

T3 100 m2 = circle with a radius of 5.5m

The protective fencing is to be erected prior to works starting and to be located to cover crown spread which will remove the need for crown lifting as the crown will be protected from plant and machinery. Consideration to be given to storage of materials, compaction of soils and maintenance of soil levels within the RPA.

Table 2 Impact Table


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5.3 Root Protection Area and Construction Exclusion Zone

The Tree Protection Plan (Appendix 3) indicates the Root Protection Area (RPA). This is the area

which is the construction exclusion zone and within which any risk of compaction and contamination

of the tree roots must be mitigated against.

5.4 Protective Fencing

It is recommended that tree protective fencing is erected around the Root Protection Area as per the

Tree Protection Plan (Appendix 3) and that the protective fencing is inspected on a daily basis and

any breaches repaired immediately.

Once protective barriers have been erected all weather signage should be used to indicate

“Construction Exclusion Zone – Keep Out”.

Once erected barriers should not be removed or altered without prior recommendation by an

arboriculturist and approval of the local planning authority.

All fencing used on the site should fully comply with British Standard 5837:2012 Trees in relation to

design, demolition and construction – Recommendations.

The fencing should be strong and suitable for local conditions. It should also take into account the

degree of construction activity on the site.

In this circumstance the protective fencing specification is as follows:

A 2 metre high galvanised tube with weld mesh infill panel fencing fence to be erected using vertical

and horizontal scaffolding poles, upright poles driven into the ground to a minimum 0.6 metre deep,

or other stout fencing to Local Authority approval with the uprights driven well into the ground,

erected in accordance with BS5837: 2012.

5.5 Specification for protection to trees during installation of utilities

Mechanical trenching for the installation of underground apparatus and drainage severs any roots

present and can change the local soil hydrology in a way that adversely affects the health of the tree.

For this reason, particular care should be taken in the routeing and methods of installation of all

underground apparatus. Wherever possible, apparatus should be routed outside RPAs. Where this is

not possible, it is preferable to keep apparatus together in common ducts. Inspection chambers

should be sited outside the RPA.

Where underground apparatus is to pass within the RPA, detailed plans showing the proposed

routeing should be drawn up in conjunction with the project arboriculturist. In such cases, trenchless

insertion methods should be used (see Table 3), with entry and retrieval pits being sited outside the

RPA. Provided that roots can be retained and protected excavation using hand-held tools might be

acceptable for shallow service runs.


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Method Accuracy mm

Bore Dia 1

mm

Max sub 2 length m

Application Not suitable for

Microtunnelling <20 100 to 300 40 Gravity-fall pipes, deep apparatus, watercourse, roadway undercrossings

Low cost projects due to relative expense

Surface-launched directional drilling

≈ 100 25 to 1,200

150 Pressure pipes, cables including fibre optic

Gravity-fall pipes, eg drains and sewers3

Pipe ramming ≈ 150 150 to 2,000

70 Any large-bore pipes and ducts

Rocky and other heavily obstructed soils

Impact moling4 ≈ 505 30 to 1806 40 Gas, water and cable connections, eg from street to property

Any application that requires accuracy over distances in excess of 5m

1 Dependent on strata encountered

2 Maximum subterranean length.

3 Pit-launched directional drilling can be used for gravity fall pipes up to 20 m subterranean length

4 Impact moling (also known as thrust-bore) generally requires soft, cohesive soils

5 Substantial inverse relationship between accuracy and distance.

6 Figures given relate to single pass: up to 300 mm bore achievable with multiple passes.

Table 3 Trenchless solutions for differing utility apparatus installation requirements

adapted from BS5837: 2012

5.6 Constraints within the Root Protection Area

Prior to and throughout the building works the RPA is to remain protected and within the area:

No materials are to be stored

Mechanical cultivation is not to take place

Soil levels must not be raised or lowered

Cement must not be mixed either in a protected area or in a place where dust or run off could compromise a protected area

no vehicular access or parking of vehicles unless provision has been made in the form of adequate ground cover which provides protection to the underlying soil structure.

In the design and landscaping phase the following should be taken into account:

a) removal of current surfaces should be undertaken by hand within the RPA to minimise disturbance of the roots;

b) walls or structural slabs should bridge over roots allowing sufficient clearance for secondary thickening or be designed to distort without cracking; or

c) pavings and other surfaces should be laid on a flexible base to allow movement and to facilitate relaying if distortion becomes excessive.

d) pavings and other surfaces should be of permeable materials through which water and nutrients are able to pass, and gaseous exchange can take place.


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6 Tree Protection Plan and Arboricultural Method Statement

6.1 Tree Protection Plan

The Tree Protection Plan (TPP – Appendix 3) and method statement details how the construction

work will be carried out in proximity to T1, T2 and T3, protective fencing specification, timing of

work, other mitigation measures where required and supervision of the protection measures during

construction.

6.2 Arboricultural Method Statement

This method statement has been prepared to ensure that T1, T2 and T3 are properly protected

throughout the development of the site and continue to represent a visual amenity in the future.

The Method Statement recommends all development within influencing distant of the tree is carried

out in accordance with BS5837: 2012 Guide for Trees in Relation To Design, Demolition and

Construction.

Developers should enforce the methods of protection identified within the statement. All contactors

must be provided with a copy of the guidelines and must also agree to them. Any failure to comply

with them must be dealt with by the developer.

The Method Statement should be read in conjunction with the architects submissions and tree

report by Birtle Tree Services Ltd.

6.3 Specifications for protection of T1, T2 and T3

The recommendations in BS 5837: 2012 Trees in Relations to Design, Demolition and Construction

must be complied with at all times.

Protective fencing (see section 5.4) must be erected prior to work beginning.

A check needs to be undertaken with the local authority to ascertain whether the trees are subject

to Tree Preservation Orders and if so local authority approval must be obtained prior to any works

being undertaken. Nevertheless the trees are not owned by the developer and as such approval

from the owners should be obtained prior to undertaking the recommended crown lift.

Any works to T1, T2 and T3 are to be carried out by a fully qualified tree surgeon and in accordance

with BS3998 (2010) Recommendations for Tree Works.

Although the Tree Protection Plan indicates the location for protective fencing, the final position and

detail of the protective fencing must be agreed with the local authority prior to site works

commencing.

The majority of the root system of a tree is in the surface 600mm of the soil, extending radially for

distances frequently in excess of the trees height. Beyond the main structural roots (close to the

base of the trunk), the root system rapidly sub-divides into smaller diameter roots. Off this main

system a mass of fine roots develop.

The shape of the main structural roots system develops in response to the need for the tree to have physical stability. Beyond these major roots, root growth and development is influenced by the


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availability of water and nutrients. Unless conditions are uniform around the tree, which would be unusual, the extent of the root system will be very irregular and difficult to predict. It will not generally show the symmetry seen in the branch system.

The parts of the root system which are active in water and nutrient uptake are very fine, typically less than 0.5 mm diameter. It is essential that conditions in the soil remain conducive to the healthy growth and maintenance of these fine roots so that the water and nutrients necessary for healthy tree growth can be absorbed.

All parts of the root system, but especially the fine roots, are vulnerable to damage. Once they are damaged, water and nutrients update will be restricted until new roots have regenerated. Vigorous young trees will be capable of rapid regeneration but the more mature a tree is the more slowly they will respond if at all.

In order to live and grow, roots need oxygen from the soil. Respiration by the roots and other soil organisms depletes this oxygen and increases carbon dioxide levels in the soil; a correct balance of these gases is normally maintained by diffusion between the soil and the atmosphere this is known as gaseous exchange. Anything, which disturbs this balance, will affect the condition of the root system.

The factors that most commonly affect this diffusion adversely and therefore damage the roots are as follows:

a) Compaction of the ground, which reduces the space between soil particles. This is particularly important on clay soils. A single passage by heavy equipment on clay soils or storage of heavy materials can cause significant damage.

b) Changing soil levels even for a few weeks. c) Covering the root area with impervious surfaces. d) A rise in the level of the water table. Roots can tolerate submersion for short periods, but a

permanent rise will deplete the soil oxygen.

Serious damage is often caused during preliminary site works by stripping the topsoil or on brown field sites removal of hard surfaces and foundations. For this reason such works should be avoided until protective fencing has been erected and within the RPA only careful digging by hand should be undertaken.

Excavations in the rooting area can sever roots. As the majority of roots are in the surface 600mm, even shallow excavations can cause damage.

Excavations for foundations, landscaping or service trenches are usually sufficiently deep to sever most of the roots, and it should therefore be assumed that all parts of the root system beyond the excavation would no longer serve the tree.

Excavation or soil stripping which sever or damage the roots may impair the stability of the tree and make it dangerous.

Whilst the intention is to prevent roots becoming exposed, if any do become exposed they need immediately to be wrapped in dry, clean hessian sacking to prevent desiccation and to protect from rapid temperature changes. Roots smaller than 25mm diameter may be pruned back to a side branch using a proprietary cutting tool such as bypass secateurs or handsaws. No roots larger than 25mm should be severed. Prior to back filling, any hessian wrapping should be removed and retained roots should be surrounded with sharp sand (builders’ sand should not be used because of its high salt content which is toxic to trees).


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Where piling is to be installed near to trees, the smallest practical pile diameter should be used as this reduces the possibility of striking major tree roots, and reduces the size of the rig required to sink the piles. Sheathed piles protect the soil and adjacent tree roots from the potentially toxic effects of concrete.

In order to distribute the weight of vehicles post development the use of a cellular confinement system is suggested (details Appendix 6).

6.4 Additional Precautions Outside Protective Fenced Areas

Oil, bitumen, cement or other materials likely to cause damage to the tree must not be stacked or discharged within 10m of tree stems or within the protective area.

Concrete mixing and washing will not be carried out within 10m of the trees.

Fires will not be lit beneath the foliage or in a position where the flames could extent to within 5m of the foliage, branches or trunks. If the fire is large then this may necessitate a distance of at least 20m.

Trees will not be used as anchorage for equipment.

Notice boards, telephone cables or other services will not be attached to any part of the trees.

Care should be taken when using cranes or other equipment near the canopy of the trees.

Whilst BS5837: 2012 does not specify the procedures to be adopted when erecting scaffolding within the RPA, the guidelines within BS5837: 2005 provide a best practice approach and the detail can be found in Appendix 5.

7 Soil Survey and British Geographical Society Survey Soil sample test holes were attempted at the site but the required 300cm depth was not achievable due to presence of stony rubble beyond 120 to 150cm Prior to the survey being undertaken the weather had been particularly poor with high levels of precipitation and the ground to the south of the site had significant surface water with poor drainage which may indicate presence of a clay subsoil. Soils that have a high level of what is termed “shrinkable clay” have a higher risk of subsidence and heave. The purpose of the soil survey is to determine whether there is a sub soil structure that is composed of shrinkable clay. When soil has a high level of shrinkable clay trees that are present or are removed can have an adverse impact on structures that are within the trees influencing distance. Such conditions can have the potential to cause subsidence problems. As an alternative to the extraction of soil samples a British Geographical Society Natural Subsidence Report has been obtained on behalf of the client relating to the site. The indication from the survey, which has been provided to the client as a separate document and can be found at Appendix 7, is that in relation to the presence of shrinkable clays there is considered to be minor potential on the site and therefore the risk is considered to be low. It should be noted that no soil sample has been sent to an external body for analysis.


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Appendix 1 Approximate location of development site boundary

Land Adjacent to Meadow Avenue, Bacup OL13 8DF

Images courtesy of Google Earth

N

T1

T3

T2


Page 13

Appendix 2

Image of T1, T2 and T3

T1

T2

T3


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Appendix 3 Tree Protection Plan

PROPOSED DEVELOPMENT SITE

T1

T2

T3

PLAN NOT TO SCALE

Development Site located at junction of Meadow Avenue and Burnley Road, Bacup

Client: Mr E McGuinness


Penn Green House, Birtle Road, Bury BL9 6US

5m0m 10m

Key

Trees

Canopy spread of T1

Root Protection Area (RPA)

Location of Protective Fencing

Boundary Line of Development Site


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Appendix 4 Tree Survey Data Explanatory Notes

This section explains the terms that may be used in the Tree Survey Data within Section 2.4.

A1.1 General Observations

A1.1.1 Numbering system: Each item of vegetation has its own unique number prefixed by a letter such that T1 = Tree 1, G2 = Group 2, H3 = Hedge 3, W4 = Woodland 4, S5 = Shrub 5

A1.1.2 Age Categories:

Young Usually less than 10 years old.

Semi-Mature Significant future growth to be expected, both in height and crown spread (typically below 30% of life expectancy).

Early Mature Full height almost attained. Significant growth may be expected in terms of crown spread (typically 30 – 60% of life expectancy).

Mature Full height attained. Crown spread will increase but growth increments will be slight (typically 60% or more of life expectancy).

Veteran A level of maturity whereby significant management may be required in order to keep the tree in a safe condition.

Over Mature As for veteran trees except management is not considered worthwhile.

A1.1.3 Species: Common names and Latin names are given.

A1.1.4 Height: Measured from ground level to the top of the crown.

A1.1.5 Stem Diameter: Taken at 1.37 m above ground level where possible. On multi-stemmed trees this measurement may be taken at ground level, though usually an indication of the number of stems and average diameter is given e.g. 3 x 30cm.

A1.1.6 Crown Spread: Measured N,E,S & W taken from the centre of the stem and usually rounded up to the nearest meter.

A1.1.7 Observations: If a tree’s position is considered to be relevant it will be commented upon (e.g. overhanging a children’s play area). Tree form and pruning history are also recorded along with an account of any significant defects. Defects and descriptive terms are dealt with in more details at the end of this section.

A1.1.8 Recommendations: Usually based on any defects observed and intended to ensure that the tree is in an acceptable condition.

A1.1.9 Priority Scale: Depending upon the threat posed by the tree, and the likelihood of failure, recommendations should be carried out according to the following priority scale:

Urgent To be carried out as soon as possible Very High To be carried out within 1 month High To be carried out within 3 months Moderate To be carried out within 1 year Low To be carried out within 3 years

A1.1.10 Inspection Frequency: An interval of 6 months, 1 year, 1.5 years or 3 years is allocated before the next inspection is due. Wherever practical, consideration should be given to seasonal changes so that deciduous trees are not always surveyed in winter when they have no leaves, or in summer when leaves may obscure branches within the upper crown.

A1.1.11 Vigour: An indication of growth rate and the tree’s ability to cope with stresses;

High Having above average vigour Moderate Having average vigour Low Having below average vigour Very Low Tree is struggling to survive and may be dying


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A1.1.12 Physiological Condition

Good Health and no symptoms of significant disease Fair Disease present or vigour is impaired Poor Significant disease present or vigour is extremely low Very Poor Tree is dying

A1.1.13 Structural Condition:

Good Having no significant structural defects Fair Some defects observed though no high priority works are required Poor Significant defects found. Tree requires monitoring or remedial works. Very Poor Major defects which will usually require significant remedial works or tree removal

A1.1.14 Amenity Value:

Very High Exceptional specimen, observable by a large number of people High Attractive specimen, observable by a significant number of people Moderate One of the above factors is not applicable Low Unattractive specimen or largely hidden from view

A1.1.15 Life Expectancy: The estimated number of years before the tree may require removal. Classified as (<10), (10 – 20), (20 – 40), or (40+)

A1.1.16 Retention Category: These are explained in detail in Table 2 Cascade chart for tree quality assessment on the following page which is taken from BS5837.

A1.2 Evaluation of Defects

A1.2.1 Cavities, wounds, deadwood etc are all evaluated as follows:

Major Such that structural integrity is, or will become, compromised and the tree is, or will inevitably become, hazardous. Significant A defect that may over time become a major defect, though not necessarily so. This will depend on the vigour of the tree and its ability to deal with decay etc. Minor A defect that is not likely to compromise the tree’s structural integrity.


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Cascade chart for tree quality assessment Category and definition Criteria (including subcategories where appropriate) Identification

on plan

TREES UNSUITABLE FOR RETENTION see Note

Category R Those in such a condition that they cannot realistically be retained as living trees in the context of the current land use for longer than 10 years

Trees that have a serious, irremediable, structural defect, such that their early loss is expected due to collapse, including those that will become unviable after removal of other U category trees (i.e. where, for whatever reason, the loss of companion shelter cannot be mitigated by pruning);

Trees that are dead or are showing signs of significant, immediate, and irreversible overall decline;

Trees infected with pathogens of significance to the health and/or safety of other trees nearby (e.g. Dutch elm disease or very low quality tree suppressing adjacent trees of better quality.

NOTE Habitat reinstatement may be appropriate (e.g. R category tree used as a bat roost: installation of bat box in nearby tree).

DARK RED

TREES TO BE CONSIDERED FOR RETENTION

Category and definition Criteria Identification on plan 1 Mainly arboricultural values 2 Mainly landscape values 3 Mainly cultural values, including

conservation

Category A Trees of high quality with an estimated remaining life expectancy of at least 40 years

Trees that are particularly good examples of their species, especially if rare or unusual; or those that are essential components of groups, or formal or semi-formal arboricultural features (e.g. the dominant and/or principal trees within an avenue)

Trees, groups or woodlands of particular visual importance as arboricultural and/or landscape features

Trees, groups or woodlands of significant conservation, historical, commemorative or other value (e.g. veteran trees or wood-pasture)

LIGHT GREEN

Category B Trees of moderate quality with an estimated remaining life expectancy of at least 20 years

Trees that might be included in category A, but are downgraded because of impaired condition (e.g. presence of significant but remediable defects including unsympathetic past management and storm damage), such that they are unlikely to be suitable for retention for beyond 40 years; or trees lacking the special quality necessary to merit the category A designation

Trees present in numbers, usually growing in groups or woodlands, such that they attract a higher collective rating than they might as individuals, or trees occurring as collectives but situated so as to make little visual contribution to the wider locality

Trees with material conservation or other cultural value

MID BLUE

Category C Trees of low quality with an estimated remaining life expectancy of at least 10 years, or young trees with a stem diameter below 150mm

Unremarkable trees of very limited merit or such impaired condition that they do not qualifying in higher categories

Trees present in groups or woodlands, but without this conferring on them significantly greater landscape value; and/or trees offering low or only temporary screen benefits

Trees with no material conservation or other cultural benefits

GREY

Taken from BS5837:2012 Trees in relation to design, demolition and construction – Recommendations


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Appendix 5

Scaffolding within the root protection area with protective fencing

Adapted from BS5837: 2005

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Appendix 6

No Dig Driveway and Parking surfaces within the Root Protection Area of Trees

The use of Geowebtm/ Neowebtm or similar, as a cellular confinement system is recommended for No Dig situations. All details can be obtained

from the supplier, Civils & Lintels, regarding the use of Geoweb tm Tree Root Protection System. Contact details are for the local branch are:

Cooper Clarke Civils and Lintels

Bloomfield Road

Farnworth

Bolton

BL9 9LP

Telephone 01204 862222

www.civilsandlintels.co.uk

In particular the following website provides the necessary design information and the company offers technical support to potential clients.

http://www.civilsandlintels.co.uk/Products/Geotechnical-Ground-Engineering/Treeguard/

http://www.civilsandlintels.co.uk/

http://www.civilsandlintels.co.uk/Products/Geotechnical-Ground-Engineering/Treeguard/

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Appendix 7 British Geological Society – Natural Subsidence Report