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Barnes & Associates

Rivermead, Skelton Road, Langthorpe, North Yorkshire, YO51 9BZ

Tel: 01423 322 371 Mobile: 07831 530 563

[email protected]

T ree R isk Assessment

Site: Snape Lime Avenue, The Avenue, Snape

Client: Mrs E Kirby

Date: 25/05/2016

Reference: BA5446

mailto:[email protected]

BARNES & ASSOCIATES

Page 2 of 34 Preliminary Risk Assessment of Snape Lime Avenue. For Snape Mrs E Kirby Our Ref. BA5446 – Printed Date 25 May 2016

© Barnes & Associates 2016

SUMMARY OF TREE INFORMATION The purpose of this report - This is an arboricultural assessment outlining the

condition and risk of the significant trees located along The Avenue, Snape located

close to the highway and adjacent to publicly accessible areas.

Its purpose is to provide initial information on the possible risk offered by the trees,

their condition, safety and suggest either further assessment or works to improve

safety and extend their safe life in addition to commenting upon the level of

suppression that the mature avenue of limes is having on the semi-mature trees in

the outer avenue.

Report Contents - The principal issues have been the ‘level of suppression that the

mature avenue of limes is having on the semi-mature trees in the outer avenue’, to

quote the recent report of Whitehead Associates Ltd, so that a comparison of

opinions may be made. The report includes:

a tree assessment, detailing significant issues with suggested works.

a tree risk assessment, which is prepared in line with best practice.

a tree schedule & survey plan within the appendices, which details the

principle management issues and trees that pose an elevated risk to the

site users and neighbours.

Background Information - Subject to physical access being available, to assess all the

significant trees on site from ground level. Problematic trees were inspected and

their details are discussed in the schedule of information, which is included in –

appendix B.

Carry out an assessment of trees situated throughout the site and carry out an assessment & risk assessment.

Produce a tree survey plan and tree risk assessment schedule setting out my survey data.

Produce a report setting out my methods, observations and opinions, and if appropriate, provide options for the management of the recorded trees.

Brief site description. The site has a well-defined green space and appears to have

had the same layout for many years.

I was provided with the general limits of the tree survey in red on the image below, used courtesy of suppliers notated on the image. I have outlined the limits of the tree survey in red on the Google Earth image below, downloaded and used courtesy of ©Google and ©third-party suppliers notated on the image below.

Risk Assessment. I have undertaken a tree survey to identify the general nature of

the trees and their relationship with significant targets. The level of detail with

which the trees have been assessed is informed by their relationship with targets.

Based on this larger trees adjacent to higher value targets were more closely

assessed than smaller trees adjacent to a lower value target.

My assessment identified 2 trees, which offer a High Risk when viewed over the

next year and poses an elevated risk of harm to site users and or neighbours, as

detailed in Table 1 below.

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These trees require mitigation / management to control the risk and meet your

requirements. High Risk Trees are highlighted Orange within my Tree Schedule in

appendix B, with their positions shown on the site plan located in appendix C, these

trees are discussed within this report.

In addition, I have identified 26 trees, which offer a Moderate Risk when viewed

over the next year and pose an elevated risk of harm to site users.

Again, these trees require mitigation / management to control the risk and meet

your requirements. Moderate Risk Trees are highlighted Yellow within my Tree

Schedule in appendix B, their positions are shown on the site plan located in

appendix C, these trees are discussed within this report.

The remaining trees are assumed to offer a Broadly Acceptable Risk at which point

the risk is already ‘As Low as Reasonably Practicable’ (ALARP).

Overall, the risk offered by the majority of the trees are low for users of the highway

and within the boundaries of tolerability that might ordinarily be applied by a

reasonable and informed landowner.

A universal principle of risk management is that the benefits of risk reduction (in

terms of reduced harm) should be balanced with the cost of that risk reduction (in

terms not only of the financial cost of implementing risk control measures but also

the loss of benefits that are conferred by the hazardous agency). Overall, finding a

balance between risks and benefits, effective risk management should seek to ‘do

no harm’.

The trees on site are a significant asset and help to both provide screening for the

site within the broader landscape, but also set the tone for the area giving it its own

unique character. As with any asset, such as a building or facility, the trees require

a level of investment to enable suitable levels of monitoring and management

works to be undertaken, to ensure continuity. If you require any further information

regarding the findings of this report, the management of the trees or would like

further information upon the value of the trees in terms of carbon sequestration or

overall asset values please feel free to contact me.

The trees as with any population of trees will require ongoing management and

assessment to maintain an acceptable level of risk and to help improve the

population as a whole. Ideally, this should be undertaken periodically and for many

sites alternating assessment between periods when trees are in and out of leaf,

allows assessments to centre on health and vitality or tree form and structure.

Please feel free to call and discuss these options if required.

The Current Recommendation. The Whitehead Tree Survey is broadly compliant with current best practice and discusses the level of suppression between the inner and outer lines of trees culminating in a complex site diagram which is informative though may prove difficult to digest by the almost 10% colour blind members of the population. Within the information however, there are several aspects in relation to the collection and presentation of information within in the original Whitehead report’s. Principally, there does not appear to be a Risk Assessment to enable a balanced approach to the prioritisation of the suggested works. This is typically the starting point for any Tree Assessment and understanding the risk offered to a site will inform management decisions and forms the basis of national and international methods of assessment. Further investigation though not detailed explicitly appear to have adopted invasive methods such as resistance drilling. Drilling devices will breach internal tree

Table 1 – Trees offering a High Risk of Harm

Tree No. Name

103 Lime

127 Lime

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defences and allow decay to spread and should therefore be kept to a minimum. Unfortunately, this does appear to have been undertaken needlessly on larger trees which have begun to develop adaptive tissue.

Some of the terminology within the report is a little unusual with repeated reference to ‘Eco-Obelisk’, which is not a recognised term in tree management and may I assume that this be best translated as ‘Previously Topped Tree’.

Elsewhere several of the recommendations appear to be based on terminology from the previous incarnations of the current British Standard for tree work rather than the current BS3998:2010. In particular, many of the recommended works appear to revolve around wholesale lopping or topping of tree canopies rather than the current practice of Retrenchment Pruning - a ‘form of crown reduction, intended to encourage development of the lower crown, which emulates the natural process whereby the crown of an ageing tree retains its overall biomechanical integrity by becoming smaller through the progressive shedding of small branches’. Overview - Inner (Original) Avenue. On first appearance, the historic management

of the of the original trees appears to have been at best ‘Harsh’, with the majority

of defects and management problems directly related to the poor pruning practice,

which have increased the level of risk and I assume elevated the cost and frequency

of pruning works.

A number of the trees do offer an elevated risk of harm and based upon my initial assessment two trees offer a high risk to site users and require significant remodelling or possibly removal depending upon the site management requirements. Elsewhere, twenty-six trees offer a moderate risk to site users, principally through large diameter deadwood (former topped stems), which can largely be controlled though minor remedial works - essentially the removal of deadwood. Many of the trees have had severe historical topping works undertaken, which is

not in line with either current or historic best practice and these works have

resulted in upper canopy dieback, though the majority trees are recovering from

these works.

The combination or deadwood removal and in some cases retrenchment pruning

works, would in the short to medium term enable the retention of this landscape

feature without significant investment.

A number of the trees are showing signs of stress (resulting from poor pruning),

borne out by the epicormics growths seen throughout the canopies. However, a

characteristic of this species is that it can be prone to the formation of epicormic

shoots in response to site and environmental changes. In this situation the limited

rooting volume due to the highway or historic root disturbance by compaction,

cultivation (ploughing) or trenching (services within the northern group) are

assumed to be contributory factors

The unfortunately excessive epicormics basal shoots, again a common trait for

Limes, prevents full inspection of the bases of trees for defects and possible decay

fungi – ideally assessment of the canopies of such trees should be undertaken in

late summer when health and vitality can be better assessed once the seasons

growth and stresses have taken effect.

Several of the trees have excellent habitat features for bats and perhaps owls or

other birds and these where possible should be retained in line with current best

practice and legislation.

The works specified within the original reports are generally excessive and outside

recognised standards. There is an over specification on reductions works and

typically harsh reduction. Canopy reduction should not ideally be undertaken and

instead reduction to limit wind-loading should consider the trees biology and

physiology.

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Unfortunately, the pruning recommended in the original reports is expected to

accelerate decline through further wounding and increase the spread/reinfection

of decay fungi/pathogens. The result of the recommended works is the expected

increase in risk offered by the trees and therefore potential liability. Trees are a self-

adapting system and provided good vitality is maintained they will effectively

defend internal issues and lay down wood in appropriate locations to maintain

safety. Where such areas are uneconomic for the trees to maintain they will

abandon growth leading to the formation of deadwood and potential instability

which needs to be assessed periodically as part of an ongoing assessment and

management of a tree.

Retrenchment works, when part of ongoing management, utilizes smaller diameter

pruning cuts, reducing wind loading and encourages the formation of a lower

canopy and reduces end loading and promotes growth to enable further reduction.

Removal of large sections of trees / reduction of canopies should be avoided,

occasionally it is specified but it is not suitable for the management of an avenue

already suffering from these works and is detailed within the Current British

Standard and as such is regarded Best Practice.

The specification of cutting into live wood (which has been specified within the

Whitehead report) should be kept to a minimum and ideally avoided following the

guidance of ‘Target Pruning’, the current best practice. The removal or reduction of

larger deadwood sections maybe required on health and safety grounds, but these

sections should be removed without entering into the live wood section, as new

wounds breach internal defences the tree has formed.

In general, tree removals, canopy removals or harsh reduction and remodelling

should be undertaken only with due regard for the wind loading effects of other

neighbouring trees as this can result in significant unintended consequences;

exposing trees to new environmental pressures which they have not developed to

withstand.

Overview - Outer Avenue. On first appearance, the level of suppression of the outer line is within reasonable limits with limited visual impact on the new trees form or vitality. The new trees within the outer line have benefited from previous good practice and generous planting centres. However, damage from grass cutting machinery and the potential for direct damage from the nearby fencing or cultivation works may begin to take its toll on the health of the new trees. My key finding in relation to the outer avenue are as follows:

The outer avenue of Lime trees is now becoming semi-mature in age and are on the

whole growing and developing well and only very minor suppression was noted on

these trees. A small number of trees (3No.) have basal damage the result of grass

cutting, one of which is severe and will compromise the future potential of the tree.

The general location of the trees is a concern in the medium to long term as further

growth of the trees is expected to deflect or more likely include the wire fencing

within the stem and this will require intervention - subject to ownership.

Additionally, the trees are located close to the current cultivation line (Plough Line)

of the neighbouring fields. Annual cultivation will limit rooting potential and in

combination with the presumed chemical applications, may affect the rooting

environment, causing stress and ultimately limit the potential of the trees.

All show adequate extension growth, though some would benefit from formative

pruning to remove crossing and some require sub-ordination of twin leaders. The

group would benefit from canopy lifting to avoid damage by agricultural equipment

and to provide sufficient clearance for pedestrians, this will be an ongoing

requirement of the sites management.

General Issues. Throughout the site a range of a more general tree related aspects,

which can affect the tree's condition or result in increased potential damage in the

medium to long term or complicate their future management were noted and are

discussed within the report.

BARNES & ASSOCIATES



TABLE OF CONTENTS

Arboricultural Assessment

Page No

1 INTRODUCTION 8

2 METHODOLOGY 9

3 SITE ASSESSMENT 11

4 CONCLUSION 18

APPENDICES

A QUALIFICATIONS & EXPERIENCE

B TREE SCHEDULE & EXPLANATORY NOTES

C SITE PLANS

D FURTHER ASSESSMENTS

E TREES & RISK

Limitations of use and copyright: All rights in this report are reserved. No part of it may be reproduced or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, or stored in any retrieval system of any nature, without our written permission. Its content and format are for the exclusive use of the addressee in dealing with this site. It may not be sold, lent, hired out or divulged to any third party not directly involved in this site without the written consent of Barnes & Associates ©.

ARBORICULTURAL ASSESSMENT

BARNES & ASSOCIATES



CTION 1 ]


An assessment of the trees adjacent to publicly accessible areas. Its purpose is to provide initial information on the possible risk offered

by trees and their condition, safety and suggest either further assessment or works to improve safety. Undertaken by a qualified

arboriculturalist.

This arboricultural assessment includes general information on tree condition, value and management.


BARNES & ASSOCIATES



INTRODUCTION

1.1 The Terms of Reference. This report is based upon a ground-based

assessment and is based upon the Visual Tree Assessment (VTA)

methodology, as devised by Mattheck (1993) in addition to Hazard

Evaluation devised by Matheny & Clark (1993). Guidance is also taken

from Lonsdale (1999) Principles of Tree Hazard Assessment and

Management. The format of the survey follows the guidelines of

British Standard 5837:2012 ‘Trees in relation to design, demolition &

construction - Recommendations’ & The ISA Tree Risk Assessment

Manual (2013).

1.2 Objective. To carry out an assessment of the condition of trees and

to identify the trees, which pose a threat to site users and neighbours,

and where such trees are located propose management to enable

reasonable risk levels to be achieved. The assessment and report are

primarily aimed at reviewing the risks from the structural failure of

the trees.

1.3 Surveyor: My name is Ian Barnes; I am an Arboricultural Association

Registered Consultant, a Chartered Environmentalist, and Fellow of

the Arboricultural Association and hold the International Society of

Arboriculture Tree Risk Assessment Qualification. I have included

further details on my experience in appendix A. My area of expertise

is tree and woodland management in both urban and rural

environments. I have provided assessments of tree health, defect

analysis, tree stability, decay mapping, and the risks from falling trees

since 1990. I frequently carry out assessments and provide risk

management advice to a wide range of government, private and

commercial clients. I have based this report on my site observations

and the provided information; I have come to conclusions in light of

my experience.

1.4 The scope of this report: This preliminary assessment is concerned with

the health and risk offered by the trees, in addition comments relating

to general management requirements are included; remedial

recommendations are included.

1.4.1 The statements made in this report do not take account of the effects

of extremes of climate, vandalism or accident, whether physical,

chemical or fire. Barnes & Associates cannot therefore accept any

liability in connection with these factors, nor where prescribed work is

not carried out in a correct and professional manner in accordance

with current good practice. The authority of this report ceases at any

stated time limit within it, or if none stated after two years from the

date of the survey, or when any site conditions change, or pruning or

other works unspecified in the report are carried out to, or affecting,

the Subject Tree(s), whichever is the sooner.

1.4.2 Assessment of the potential influence of trees upon buildings or other

structures resulting from the effects of trees abstracting water from

shrinkable load-bearing soils was not included in my instruction and is

not considered here.

1.5 Tree Tags: The trees have been previously tagged.


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METHODOLOGY.

2.0 Potential Risk from Trees. Trees, unlike built structures are a dynamic structure and

offer several specific management issues that need to be considered. Reasonable risk

management generally aims to provide trees that can be regarded stable in a normal

/ foreseeable, storm event.

2.1 Wind Speed. In general, the windiest parts of the UK are the north and west. This is

because the prevailing west to south-westerly winds across the UK lead to northern

and western areas being typically more exposed than the south and east.

2.1.1 There are also a lot of

localized effects with most

hills, mountains and coasts

being windier than low-lying

inland areas. Wind speed

increases as you go upwards

away from the friction caused

by the earth's surface. This

also explains the windier

coasts as the sea surface

produces less friction than

the land.

2.1.2 In this region, we expect to

receive peak wind speeds

around of 22 to 24 m/s based

upon information published

in the UK National Annex to

Eurocode 1 - Actions on

structures Part 1-4: General

actions - Wind actions. This

equates to a force 9 Strong

Gale on the Beaufort Wind Scale. I have included further general information upon the

Tree & Risk in - appendix E.

2.2 Target evaluation. To enable a balanced approach to the site assessment I undertook

an initial assessment of the associated risks on site to identify areas of high public

access, areas where trees are within striking range of valuable or fragile structures or

high human occupancy locations. Targets are broadly zoned in the ’Target’ ranges

based on the levels of occupation, population and value. These were assumed to be

generally low target areas with the site having occasional to frequent occupation.

2.3 Risk Assessment. The assessment follows the general principles of Risk Assessment;

Risk assessment is important to reduce the risk of injury to people, property damage

or disruption of services. The International Society of Arboriculture (ISA) Tree Risk

Assessment Methodology takes a qualitative rather than quantitative approach to risk

assessment. The system uses the output of matrix 1 (copied below) to compare the

likelihood of failure of a tree or tree part, the likelihood of impacting the target and

the potential consequences of failure.

2.4 The matrices generate an output in matrix 2 (above), describing the risk offered by the

trees in line with general risk assessment methodologies; these are arranged into

bands differentiated by coloured text within the tree schedule. Highlighted above are

the colours representing the risk band of indices.

Matrix 1. Likelihood of failure

Likelihood of failure

Likelihood of Impacting Target

Very low Low Medium High

Imminent Unlikely Somewhat

likely likely Very likely

Probable Unlikely Unlikely Somewhat

likely Likely

Possible Unlikely Unlikely Unlikely Somewhat

likely

Improbable Unlikely Unlikely Unlikely Unlikely

Matrix 2. Risk Rating matrix

Likelihood of failure & impact

Consequences of Failure

Negligible Minor Significant Severe

Very likely Low Moderate. High Extreme

Likely Low Moderate High High

Somewhat likely

Low Low Moderate Moderate

Unlikely

Low Low Low Low


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2.5 The UK Health and Safety Executive (Anon. 2001) suggests that "an individual risk of

death of one in a thousand per annum should on its own represent the dividing line

between what could be just tolerable for any substantial category of workers for any

large part of a working life, and what is unacceptable for any but fairly exceptional

groups. The Tolerability of Risk framework (ToR) (HSE 2001) is a widely accepted

approach to reaching decisions on whether risks are broadly acceptable,

unacceptable, or tolerable.

2.6 In respect of trees, some risks cross the Broadly Acceptable 1/1,000,000 boundary,

but remain tolerable. This is because any further reduction would involve a

disproportionate cost in terms of the lost environmental, visual, and other benefits, in

addition to the financial cost of controlling the risk. For members of the public who

have a risk imposed on them ‘in the wider interest of society’ this limit is judged to be

an order of magnitude lower – at 1 in 10, 000 per annum." Furthermore, “HSE believes

that an

2.7 individual risk of death of one in a million per annum for both workers and the public,

corresponds to a very low level of risk and should be used as a guideline for the

boundary between the broadly acceptable and tolerable regions” as demonstrated in

the table opposite.

2.8 Importantly, to enable tree assessors to provide appropriate management guidance,

it is helpful to have some understanding of the tree owner’s management preferences

prior to assessing the trees.

2.9 Barnes & Associates can offer guidance on but cannot set the threshold of risk at which

you manage your trees. We consider in line with normal health and safety guidelines

that 1 in 10,000 an appropriate level and I have formulated management proposals

on this basis.

2.10 The Advisory Risk Threshold provides information upon priority with trees with the

highest risk rating with the greatest target values requiring work urgently. Where the

priority of trees is recorded as being low and a low target value, works required to

improve the trees risk of harm, are expected to be undertaken as part of the normal

estate management.

Advisory Risk Thresholds

Thresholds Description Action

Unacceptable Risks will not ordinarily be tolerated

Control the risk

1/1 000

Unacceptable (where imposed on others) Risks will not ordinarily be tolerated

Control the risk

Review the risk

Tolerable (by agreement) Risks may be tolerated if those exposed to the risk accept it, or the tree has exceptional value

Control the risk unless there is broad stakeholder agreement to tolerate it, or the tree has exceptional value

Review the risk

1/10 000

Tolerable (where imposed on others) Risks are tolerable if ALARP

Assess costs and benefits of risk control

Control the risk only where a significant benefit might be achieved at reasonable cost

Review the risk

1/1 000 000 Broadly Acceptable Risk is already ALARP

No action currently required

Review the risk


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SITE ASSESSMENT 3.1 Date of Inspection. 10th & 20th May 2016.

3.2 Weather conditions. The weather was bright with good visibility.

3.3 Boundaries: The site boundaries are well defined by fencing.

3.4 Tree Population. The trees compose of a mature central avenue of trees

located in the highway verge and a maturing outer avenue of trees.

3.5 Principal Targets. The trees are located close to the highway (The Avenue )

& an informal footpath that travels roughly east - west between the inner

and outer trees and these are assumed to be the principal targets.

3.6 Pedestrian Access. Pedestrian access is possible around the site, though

access appears to be concentrated on the well-defined footpath network

and is assumed to be limited to reasonable weather conditions.

3.7 Vehicle Access. Vehicle access although within the national speed limit the

junction at the western end of the site and the bend, and 30mph limit at the

eastern end, in addition to the presence of the trees which appears to limit

the speed of vehicles, which is expected to limit the potential for impact.

3.8 Condition of Trees. This inspection provides an initial assessment of the

principal trees, within the existing site along with landscape and

environmental constraints.

3.8.1 The trees have been assessed from ground level only. Information upon the

trees is located in the Tree Schedule in appendix B.

3.9 Identification and location of the trees. I have illustrated the location of the

recorded trees on the site plans included and referenced BA5446/A. A

numbered copy is included in - appendix C. Trees are shown on the plan,

which is for illustrative purposes only and should not be used for directly

scaling measurements.

3.10 My information is loosely based upon the information within the various

A.Whitehead Associates Ltd reports and I have adopted the same numbering

methodology to avoid any confusion.

3.11 Visual assessment of trees. The assessment of the trees was undertaken

from ground level using Visual Tree Assessment (VTA), this is a non-invasive

method of examining the health and structural condition of individual trees.

The assessment provides information on the condition of the roots, trunk,

main branch structure, crown, buds and leaves together providing an

assessment of general tree health and vitality.

3.12 Basic decay detection tools such as a Nylon Mallet & Steel Probe were

utilised to determine whether further investigation is required, using more

invasive methods.

3.12.1 Other than where the height of a tree is critical to the outcome of the

assessment, approximately 1 in 10 trees are measured using a clinometer

and the remainder estimated against the measured trees. Where possible

canopies are measured using either a tape or measuring wheel, where

access is restricted, they are estimated. Stem diameters are measured using

a rounded down diameter tape to avoid variations due to stem shape,

otherwise where trees are in a group and / or not accessible the stem’s

mean stem diameters are estimated to provide a reasonable basis for tree

protection.

http://www.cbatrees.com/decay.html


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3.13 Problem trees. The Lime T103 offers a High Risk, through the potential failure

of the main stem which requires urgent closer assessment. The tree as with

many of the trees in the line have been historically topped, resulting in a

series of tightly developing ascending main leaders. One of these appears to

have failed naturally and one appears to have been removed, leaving an

upright secondary leader supported by a main stem affected by localised

decay as shown below. The stem, which has a marked hollow is unlikely to

recover leaving the stem predisposed to failure.

3.13.1 Tree T103, has good overall vitality, and is redeveloping a secondary lower

stem which could be maintained at little cost to provide continuity, maturity

to the line in addition to valuable biodiversity in the form of a developing

hollow.

3.13.2 An additional Lime T127 offers a High Risk, through potential failure of the

dead main stem, the result of historically topping works as shown below.

The stem, which has a marked hollow is unlikely to recover leaving the

stem predisposed to failure.

3.13.3 Tree T127, has good overall vitality, and is redeveloping a secondary lower

stem which could be maintained at little cost following removal of the dead

section to provide continuity, maturity to the line.

3.13.4 In addition, to the high risk trees a further 26 trees offer a Moderate Risk of

harm to both highway and footpath. Information upon these trees is located

in the Tree Schedule in appendix B, though in general the risk offered by

these trees is the result of large diameter deadwood formation resulting


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from harsh historic works that have centred around topping and lopping.

These works have caused canopy decline, topping and lopping are

considered out of date practices. The general vitality of the trees indicates

good recovery and suggests that they have sufficient resources to develop

compensatory adaptive growth as the secondary canopy develops.

3.13.5 Several trees at the western end of the group principally the Ash

T135(shown below) & T136 have some canopy asymmetry as a result of

additional light levels and increased exposure to prevailing winds,

although by virtue of their location do provide a valuable wind break and

help shelter the remainder of the group. These trees will require careful

remodelling to balance the risk offered by branch failure with the level of

shelter that they provide for the remaining group. By way of an example I

have indicated the likely level of branch reduction with the red line on the

photograph below.


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3.14 General Site Issues. Whilst on site a range of general arboricultural issues

were seen which have the potential to affect the development of trees and

may result in future problems or which may result in elevated management

costs for the site in the future.

3.14.1 Trees throughout the site appear to be in a reasonable state in light of their

current maturity, recent localised changes and as a result of historic

management.

3.14.2 Direct damage to structures, several trees are located close to the bridge at

the NE of the site and are expected to cause direct damage through

deflection resulting from further growth. As indicated on the photograph

below. Ideally this structure should more closely assessed or the trees

removed to protect the feature.

3.14.3 Ivy is developing through a number of the

trees, throughout the site. It has a variety of

conservation benefits. However, if left

unmanaged it may be considered unsightly

and more importantly, can create problems

for efficient management by obscuring

structural defects and may increase the

weight of a tree's crown and the 'sail' effect

during the wet windier winter months –

Ideally this should be controlled throughout

the site.

3.14.4 Trenching, a service of

unknown age and depth

is located between the

inner and outer line of

trees indicated by the

dashed line on the

photograph opposite.

This is expected to have

caused localised root

severance, compaction

and potentially soil level

changes and could be

related to the decline of trees, which increases the chances of deadwood or

failures due to pathogens. Ideally, these aspects should be monitored locally.

In particular, trees can become susceptible to colonisation with Honey

Fungus, which can readily breach defences in the stem versus the roots.

Ideally, in this situation the soil close to the stem should be removed to the


BARNES & ASSOCIATES



original soil depth using an ‘Air Spade’ to a distance of 3 times the stem

diameter and the void filled with a porous material such as gravel or perlite

to avoid a trip hazard.

3.14.5 Compaction, affects to the soils between the inner and outer lines of trees

the result of both vehicle activities, horses and pedestrians. This damage has

the potential to restrict the development and efficiency of roots. Ideally,

following works to

improve the

rootzone, the area

should be mulched

to restrict the

development of

competing weed

species, to increase

the soils organic

content helping to

mimic the conditions

found in a natural

woodland. Ideally, access to the site particulate during wet periods should be

limited.

3.14.6 Most plants form mycorrhizal associations with fungi which live in the soil.

Mycorrhizal fungi benefit trees by linking directly with tree roots to provide

the equivalent of an extended root system. They gather essential nutrients

otherwise inaccessible to the tree and act as a barrier to certain disease-

causing organisms. These organisms may enter the tree if fertilisers and

chemicals encourage the growth of non-mycorrhizal roots. Mycorrhizae help

the tree to cope with extremes in growing conditions. However, they are

sensitive to compaction, prolonged periods of waterlogging or drying out in

summer and inorganic chemicals such as fertilizers or herbicides and as such,

these should be avoided wherever possible.

3.14.7 Low tree canopies, are

affecting pedestrian

access, and are

developing into the

highway, with some

trees having evidence

of damage from high

sided vehicles. The

tree canopies should

ideally be lifted to 2.5

metres above the

footpath and 5.2

metres above the carriageway to avoid damage to both the trees and

vehicles.


BARNES & ASSOCIATES



3.14.8 Tree Guards are

located close to many

of the younger trees, if

retained too long this

can cause direct

abrasion damage to

stem and lower

branches, ideally

guards should be

removed / relocated

before they impact the

trees they are

protecting.

3.14.9 Adaptive Growth - Trees are dynamic structures that economically transfer

their own weight and any additional forces such as wind and weather,

through a network of branches into the main stem to the root which in turn

transfers the force into the local supporting soils, through ever-changing

Tension & Compression within the wood of the tree; described as the ‘Axiom

of uniform stress’. Initially defined in the Body Language of Trees by Claus

Mattheck and Helge Breloer (which has now been refined into the system

commonly known as ‘Visual Tree Assessment’ (VTA)) as "the tendency for all

self-optimizing structures to make as economic a use of their material as

possible, and to become as strong as necessary to perform their function",

as indicated by the ribbing below the codominant leader on the tree shown

opposite.

3.14.10 Topping, often removes 50 to 100 percent of the leaf-bearing crown of a tree.

Because leaves are the food factories of a tree, removing them can

temporarily starve a tree. The severity of the pruning triggers a sort of

survival mechanism that causes a tree to produce multiple shoots below each

topping cut and comes at great expense to the tree. These shoots develop

from buds near the surface of the old branches. Unlike normal branches that

develop in a socket of overlapping wood tissues, these new shoots are

Included union

Adaptive growth

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BARNES & ASSOCIATES



anchored only in the outermost layers of the parent branches. The new

shoots grow quickly, as much as 3 meters in one year, in some species.

Unfortunately, the shoots are prone to breaking, especially during windy

conditions. The irony is that while the goal was to reduce the tree’s height to

make it safer, it has been made it more hazardous than before and as a result

tree requires periodic assessment and intervention.

3.14.11 Structural Issues, many tree species are susceptible to the formation of tight

of included unions. Usually, indicated by a V-shaped fork. This is a serious

hazard for several reasons. Where the bark is between the stems, the tree

will never be able to bind the stems together by fusing the tissues. Included

bark often remains alive and growing. As the stems grow in diameter, they

force the fork apart. The point below, where the two stems are really joined,

is unable to adjust to this pressure and tends to crack. Such unions are

observed on site both and as shown above, within both the inner and outer

line and should ideally be improved through formative pruning.

3.14.12 Suppression, the development of the outer line of trees appears to be largely

normal with only minor

deviation of form or

deflection of stems being

observed. This is assumed

to be largely a benefit of

the good foresight of

providing good

separation distances

(typically around 8

meters) at planting.

Providing current growth

is maintained the outer

line is expected to achieve a similar height as the inner line and provide

shelter in the medium term.

3.14.13 Available Space, due to the very close

cultivation line (Plough Line) within

the neighbouring fields shown

opposite on the aerial image,

downloaded and used courtesy of

©Google and ©third-party suppliers

notated on the image. Annual

cultivation is expected to damage

rooting and in combination with

chemical applications may affect the

rooting environment for trees

negatively and ultimately limit the

potential of the trees.


BARNES & ASSOCIATES



CONCLUSION

4.0 Generally, the trees are in good condition and appear to have good vitality.

4.1 Tree Management. The site would benefit from an improvement in the level

of and frequency of tree assessment. This increase in the level of

management would not only help improve the day to day level of safety, but

would provide the range of benefits offered by the trees.

4.1.1 Ideally, a management plan should be prepared to help provide a more

detailed insight into the population of the trees. To provide appropriate

forthcoming works, planting opportunities and to help identify both

immediate and ongoing management to help stabilise the tree population.

4.1.2 In addition to this, there are opportunities to help provide additional trees

through the establishment of replacement trees or the improved

management of natural regeneration.

4.1.3 Trees potentially live for many generations their environment and people’s

attitudes can change significantly over their life spans, and management

practices can change. Plans and procedures should be reviewed regularly to

ensure they remain effective and current, particularly in relation to climate

change issues.

4.2 Additional Assessment. A number of trees require more detailed assessment

to understand the internal condition of the stem and or branches and this is

detailed in appendix C.

4.3 Remedial Tree Works. A number of trees contain defects and require works

to improve their condition. These works are detailed within the tree schedule

listed in appendix B. Once these have been undertaken the issues related to

tree damage can be better understood.

4.4 Additional and ongoing Requirements. The site will require ongoing

assessment to maintain a reasonable level of safety. I have included an

outline of further assessments within appendix D, with information upon the

preferred time scales. I can send a budget for this if required.

4.5 Limiting Site Access. It is reasonable to assume a ‘Storm’ of force 10 using the

Beaufort Scale (55 - 63 miles per hour of wind speeds on land) will occur

annually and such a risk should be built into the site management. Recent

work has shown even sound trees that would typically be regarded as safe

can fail during high winds through various factors relating to wood

physiology, dynamics and the relationship between the root system and the

supporting soils.

4.5.1 Typically, trees have evolved to fail in part, i.e. twigs and branches are

sacrificed / fail from a parent tree rather than the tree being lost entirely.

Observations at various sites have found that twigs and branches, can break

from trees at wind speeds of as little as 31 miles per hour, the upper limit of

a ‘strong breeze’ as detailed in Beaufort Scale 6 (25 - 31 miles per hour).

4.5.2 Such branch failures are difficult to predict with any great level of detail and

as such, I would recommend a defensive position is best adopted. In light of

this, I would suggest that changes to the opening arrangements are

considered and that access to the site is restricted when the wind speeds

approach 'Near Gale' or ‘Moderate Gale’ - Beaufort Force 7, 32-38 miles per

hour or 30mph based upon normal broadcast weather forecasts.


BARNES & ASSOCIATES



4.5.3 However, in light of the access requirements, this is not always achievable

and instead management to improve safety is the only realistic alternative.

4.6 Trees subject to statutory controls. If the trees are covered by a tree

preservation order or located in a conservation area or other legal planning

constraint works may be restricted. The works specified within this report

are necessary for reasonable management and should be acceptable to the

local authority.

4.7 Implementation of works. I would always suggest that you get at least three

fixed price quotations before deciding upon a contractor to undertake the

works on your behalf. If required, I can prepare a detailed breakdown of the

works for tendering purposes. Work schedules can also be supplied including

an appropriate technical specification for the various arboricultural and

horticultural operations.

4.7.1 You should ensure that any contractor employed for the above works is

suitably qualified and experienced, familiar with current best practice and

covered by current, public, products, and employee liability insurance, to an

adequate level. I would advise that any Arboricultural work is carried out by

a reputable contractor from the local authority list if available, or

alternatively one approved by the Arboricultural Association

(www.trees.org.uk) or Trustmark (www.treecareapproved.org).

4.7.2 The contractor should carry out all tree works to BS3998 (2010) Tree Work –

Recommendations and/or the European Tree Pruning Guide - European

Arboricultural Council (English Version) and the Industry Code of Practice for

Arboriculture: Tree Work at Height (Edition 1, February 2015). Works should

be undertaken in strict accordance with current arboricultural best practice

ensuring that any pruning works accord with current target pruning

methodology. They should be fully conversant with current Arboricultural

best practice and adhere to all relevant legislation including the New Road &

Street Works Act 1991 for works in proximity of highways, and The Working

at Heights Regulation 2005. In addition to the dangers & legislation associated

with working close to Electrical Supplies.

4.7.3 Additionally, they should be aware of the Wildlife and Countryside Act 1981.

In addition, the amendments of 1991 and its implications to tree works.

Works should be planned to avoid times when birds are nesting, and be

aware that a bat survey may be needed on significant tree hollows. If bats

are discovered during inspection or subsequent work, English Nature must

be informed immediately.

4.8 Legal Duty. Tree owners have a statutory duty of care under the Health and

Safety at Work Act 1974 and the Occupiers Liability Acts of 1957 & 1984 to

ensure that members of the public and staff are not to be put at risk because

of any failure by the owner and to take all reasonable precautions to ensure

their safety.

4.8.1 A risk assessment is required under the Management of Health and Safety

Regulations 1999. There is a need to inspect trees in or near public places, or

adjacent to buildings or working areas to assess whether they represent a

risk to life or property, and to take remedial action as appropriate.

4.9 Future considerations. Trees are living organisms whose health and condition

can change rapidly. The health, condition and safety of trees should be

checked on a regular basis. In addition to the professional inspection, a tree

owner should inspect their trees personally on a regular basis, in particular

after stormy weather and high winds.

http://www.treecareapproved.org/

APPENDICES

Barnes & Associates



APPENDICES

APPENDICES

Barnes & Associates



APPENDIX A – BRIEF QUALIFICATIONS AND EXPERIENCE OF IAN BARNES Registration Schemes:

Arboricultural association Registered Consultant (49)

Qualifications:

Higher Diploma in Arboriculture (H.N.D Arb)

National Diploma in Horticulture & Arboriculture (N.D.Ht/Arb)

Arboricultural Association Technicians Certificate (Tech.Cert. (Arbor.A))

International Society of Arboriculture – Tree Risk Assessment (TRAQ)

Membership grades by peer review:

Chartered Environmentalist (CEnv)

Corporate Member Institute of Horticulture (MI Hort)

Fellow of the Arboricultural Association (F.Arbor.A)

Professional member Consulting Arborist Society UK.

Practical experience:

I have worked in the Arboricultural Industry since 1987. Firstly as a climbing Arborist in both the public and private, sector, undertaking a wide range of practical operations

on a variety of sites, before becoming a gang foreman. I set up and ran my own Arboricultural contracting business for 15 years, though this is now under new ownership. I

have developed an arboricultural consultancy practice since 1993, working throughout England for clients in both the public and private sector.

Continuing professional development:

As part of my ongoing education, I am a member of a range of related Arboricultural bodies. Including the Arboricultural Association (AA), International Society of

Arboriculture (ISA), Royal Forestry Society (RFS), Forestry Contracting Association (FCA), and Consulting Arborist Society (CAS) of which I am a professional member. I am a

corporate member of the Institute of Horticulture (MI Hort) and a Fellow of the Arboricultural Association (F.Arbor.A). An inclusive member of the British Mycology Society (BMS)

in addition to being a Chartered Environmentalist (CEnv).

I am a registered consultant of the Arboricultural Association. I regularly attend seminars and training events on issues relevant to Arboriculture these include events focusing

on General Tree Management, Veteran Tree Management, Tree Health, Tree Pest management, Tree Diseases management, Trees Biology & Morphology, Tree Stability, Wind

Loading of Trees, Tree Risk Assessment, in addition to keeping an upto date level of CPD.

I am a licensed user of the Quantified Tree Risk Assessment (QTRA) System and regularly attend updates. I am a trained user of Picus ‘Acoustic’ Tomography and have

attended training to extend my knowledge in this area. I am trained in the use of thermal imaging as an aid to detecting defects in trees.

Relevant experience:

My career to date has involved me in a variety of tree care, dealing with trees in many different environments, and with differing management aims, these included: Tree

planting schemes, including Woodland Design & Management, Detailed Health and Safety Appraisals, Tree inventories / population surveys, Management & selection on

both proposed and active development sites, Advice upon trees in relation to structures, Additional areas of work such as Contract Specification & Management, Planning

applications, Expert Witness.

This has provided me with a range of experience, enabling me to comment upon trees and their management, in line with current best practice. Full CPD and training record

can be forwarded upon request.

APPENDICES

Barnes & Associates



APPENDIX B – TREE SCHEDULE & EXPLANATORY NOTES The following survey has been prepared from a visual assessment taken from ground level without any detailed investigation. Observations are based upon the body language of the trees and any visual indicators present at the time of inspection. This survey should be regarded as a preliminary overview; ongoing inspections will be required as specified individually. In most situations the health, condition and safety of trees should be checked on a cyclic basis, alternating between early and late seasons to ensure a full picture of tree health is established. Inspections should only be carried out by a suitably qualified arborist. Similarly, numerous potential defects may not be detectable dependent upon timing of inspection, in particular, wood decay fungi, which may only occasionally produce external fructifications annually (rather than perennially), or may not provide external symptoms until an advanced state is achieved. Reasonable risk management generally aims to provide a tree that can be regarded stable in a normal / foreseeable, regularly experienced storm events i.e. force 10 storms. The level of risk offered by the tree will be significantly greater as the wind speed that the tree is exposed to increases beyond this level. Additionally the threat from aerial parts i.e. Tight unions may remain even following works, although failures of such parts are likely to be limited to small diameter branches and to periods of extreme weather. As an arborist, I am a tree specialist and use my knowledge, education, training and experience to examine trees, recommend m easures to enhance their beauty and health, and attempt to reduce the risk of living near trees. As a client, you may choose to accept or disregard these recommendations, or seek additional advice. As an arborist I cannot detect every condition that could possibly lead to a tree or limb failure. Trees are living organisms that may fail in many ways, some of which we do not fully understand. Conditions are often hidden within the tree and below the ground. As arborists, we cannot guarantee that a tree will be healthy or safe under all circumstances, or for a specified period of time. Sometimes trees may appear "healthy," but may be structurally unsound. Likewise remedial treatment, like any medicine, cannot be guaranteed. Treatment, pruning and removal of trees may involve considerations beyond the arboricultural perspective, such as property boundaries and ownership, disputes between neighbours, planning issues, sight lines, landlord-tenant matters etc. Arborists cannot take such issues into account unless complete and accurate information is given to them. Likewise, as an arborist I cannot accept any responsibility for the authorization r non-authorization of any recommended treatment or remedial measure. Furthermore, certain trees are borderline cases as to whether they should remain or be removed. If conditions change a tree may need further monitoring in the future to determine its health and structure. Trees can be managed, but they cannot be controlled, and to live near a tree is to accept some degree of risk. Mathematical abbreviations: > = Greater than, < = Less than. Measurements / estimates: All dimensions are estimates unless otherwise indicated. Measurements taken with a tape or clinometer are indicated with a ‘#’. Less reliable estimated dimensions are indicated with a ‘?’. Tree number: Numbered Tag attached to each stem usually on the inside face of the stem at roughly 2.5 metres. Where the number is followed by a C or G this demotes that the tag refers to a Compartment or Group. Name: Tree species are detailed by their common name- Latin ca ne provided upon request. Age: I record the age as an estimate of the tree likely span for guidance only i.e: Y Young Recently established/planted tree. SM Semi Mature Fully established and growing with high vigour EM Early Mature The first third of its likely expected life span M Mature The middle one third of its likely expected life span

EOM Early Over Mature Clear reduction in vitality, typically small deadwood early canopy retrenchment. OM Over Mature The later one third of its likely expected life span with sign of canopy retrenchment. V Veteran An aged example of the species, typically with defects & conservation value S Senescent Beyond its expected Life span possible of historical interest or in a state of decline

Height: I estimate height to the nearest metre to the mean height. Height to underside: I estimate height to the nearest half metre to the mean underside of the canopy. Diameter: These figures relate to a measurement of the stem at 1.5m above ground level recorded in millimetres, measured with a rounded down diameter tape. Figures prefixed with MS denote trees or shrubs with multiple stems. Canopy (N S E W): I estimate the distance of the canopy radius to the nearest metre to provide a mean distance of separation between the stem and the outer canopy.

APPENDICES

Barnes & Associates



Vitality: Is a personal assessment of the tree's growth rate in the current season, in comparison to other trees within the locality, region and an indicator of the tree likely response to site change. D - Dead A dead or very low vitality tree L - Low / Declining A tree in noticeable poor state N - Normal A tree of typical vitality P - Poor A tree of low vitality F - Fair A tree of lower vitality G - Good A tree of high vitality Safe Life: Is a personal assessment of the trees likely expected remaining safe life span in years, assuming the site management continues as it i s at present or the tree is protected from significant environmental change. Trees can reverse even enter into serious decline with site changes, likewise the expected safe life can be significantly improved following changes / improvements to site management and following remedial works. 40 or more Good vitality a tree a tree with high potential. 10 to 20 Early reduction in vitality / reducing foliage cover. 5 or less Serious decline or very low vitality tree 20 to 40 Normal vitality a tree in good health. 10 or less Marked decline / reduced foliage cover. 1 or Less A dead or almost dead tree with very low vitality tree Category: I included a method-adopted form BS5837 to enable rapid assessment of a trees quality detailed below.

Comments / Observations: General comments referring to tree health, structure and condition. Management Options: Comments detailing remedial works required improving immediate safety or improve the management of the tree. Priority: Guidance for the time scale in which works should be completed, from the date of the report. Tree Risk Assessment: The International Society of Arboriculture (ISA) Tree Risk Assessment Qualification (TRAQ) takes a qualitative rather than quantitative approach to risk assessment. It uses matrices to compare the likelihood of failure of a tree or tree part, the likelihood that it will impact the target and the potential consequences of failure. Unless stated otherwise the risk assessment assumes the risk offered Over the next year.

Category and definition Criteria (including subcategories where appropriate) Colour Code

Trees unsuitable for retention (see Note)

Category U Trees that 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 and are not expected to respond to pruning. Trees that are dead or are showing signs of significant, immediate, and irreversible overall decline or infected with pathogens of significance to the health NOTE Category U trees can have existing or potential conservation value, which it might be desirable to preserve though canopy reduction or removal.

Red on Plan

s Trees to be considered for retention

1 Mainly arboricultural qualities 2 Mainly landscape qualities 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.

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)

Green on Plan

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

Trees downgraded because of impaired condition, or having remediable defects, such as unsympathetic past management or damage.

Usually growing as groups or woodlands, such that they attract a higher collective rating than they might as individuals

Trees with material conservation or other cultural value Blue on

Plan

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 150 mm

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

Trees present in groups or woodlands, Trees with no material conservation or other cultural value Grey on

Plan

Matrix 1. Likelihood of failure

Likelihood of failure

Likelihood of Impacting Target

Very low Low Medium High

Imminent Unlikely Somewhat likely likely Very likely

Probable Unlikely Unlikely Somewhat likely Likely

Possible Unlikely Unlikely Unlikely Somewhat likely

Improbable Unlikely Unlikely Unlikely Unlikely

Matrix 2. Risk Rating matrix

Likelihood of failure & impact

Consequences of Failure

Negligible Minor Significant Severe

Very likely Low Moderate. High Extreme

Likely Low Moderate High High

Somewhat likely Low Low Moderate Moderate

Unlikely Low Low Low Low

APPENDICES Barnes & Associates



Preliminary Arboricultural Assessment - This should not be referred to as a specification of Arboricultural Works.

Tag No. Species

Ag

e

He

igh

t

He

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t to

c

an

op

y

No

rth

So

uth

Ea

st

Wes

t

Vit

ali

ty

Sa

fe L

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Ca

teg

ory

Ste

m D

ia

(mm

)

Observations Risk

offered by tree

Target Assessment

Management options Priority for

Action

Risk offered

following Works

T101 Common

Lime M 15 4 4 4 5 4 Fair 20+ C2 700

Compaction by vehicles within in rootzone. Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Cavities are visible within the main branches. Woodpecker hole suggests a volume of decay.

Moderate

Canopy overhangs the highway and pedestrian

access.

Remove large deadwood only. Crown lift to 5.2m to enable vehicle access.

<1 year Low

T102 Large-leaved Lime

M 24 4 8 8 5 5 Fair 20+ C2 1000

Compaction by vehicles within in rootzone. Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Cavities are visible within the main branches. Branch failures are visible within the canopy. Woodpecker hole suggests a volume of decay.

Moderate


access.

Remove large deadwood only. Retrench the canopy in stages to create a smaller canopy by a maximum of 1.5M. Crown lift to 5.2m to enable vehicle access. or Consider veteran management to retain the stem and provide habitat.

<1 year

Low


M 20 4 9 8 5 5 Fair <10 C2 1000

The stem has a significant structural issue. Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Cavities are visible within the main branches. Branch failures are visible within the canopy. Wounding from branch failures can be seen within the outer canopy. Significant asymmetry to the canopy. Elongated branches visible within the canopy. High-end loading can be seen on branches. Branches are predisposed to failure. Poor final pruning cuts throughout the canopy. Canopy has been reduced (topped) & redeveloped.

High


access.

Canopy remodelling to reduce canopy volume. Retrench the canopy in stages to create a smaller canopy by a maximum of 1.5m. or Consider veteran management to retain the stem and provide habitat. or Remove and grind the stump. Establish a replacement tree elsewhere.

<3 months Low

T107 Common

Lime M 12 4 4 4 4 4 Fair 20+ C2 600

Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Canopy has been reduced (topped) & redeveloped.

Moderate


access.


<1 year Low


M 13 4 6 4 4 4 Fair 20+ C2 700

Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Elongated branches visible within the canopy. Poor final pruning cuts throughout the canopy. The canopy has been lopped recently and likely to develop a poorly formed canopy. Canopy has been over pruned significantly. Canopy has been reduced (topped) & redeveloped.

Moderate


access.

Remove large deadwood only. Canopy remodelling to reduce the lower northern canopy volume. Crown lift to 5.2m to enable vehicle access.

<1 year Low

T118 Common

Lime M 16.5 4 5 5 5 5 Fair 20+ C2 700

Small cavity visible within the main stem. Hollows in the stem at 3m & 4m. Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Branch failures are visible within the canopy. Wounding from branch failures visible. Canopy has been reduced (topped) & redeveloped.

Moderate


access.

Ideally - Undertake Tomography of noted fault.at 3.5m Remove large deadwood only. Canopy remodelling to reduce canopy volume required. Crown lift to 5.2m to enable vehicle access.

<6 months Low

T119 Common

Lime M 11 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600

Single stem with buttress shooting. Small hollow visible in the main stem. Large deadwood can be seen in the outer canopy. Hollows in the stem at 3m & 4m.

Moderate


access.

Remove large deadwood only. Crown lift to 5.2m to enable vehicle access. Undertake Tomography of noted fault.at 4m.

<1 year Low





Tag No. Species

Ag

e

He

igh

t

He

igh

t to

c

an

op

y

No

rth

So

uth

Ea

st

Wes

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Vit

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ty

Sa

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ife

Ca

teg

ory

Ste

m D

ia

(mm

)

Observations Risk

offered by tree

Target Assessment


Action

Risk offered

following Works

T120 Common

Lime M 11 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600

Single stem with buttress shooting. Large deadwood can be seen in the outer canopy.

Moderate


access.


<1 year Low

T121 Common

Lime M 11 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600


Moderate


access.


<1 year Low

T124 Common

Lime M 11 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600


Moderate


access.


<1 year Low


M 11 4 4.5 4.5 4.5 4.5 Fair <10 C2 600

The stem has a significant structural issue. Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Branch failures are visible within the canopy. Wounding from branch failures can be seen within the outer canopy. Branches are predisposed to failure. Poor final pruning cuts throughout the canopy. Canopy has been reduced (topped) & redeveloped.

High


access.

Remove large deadwood only. Consider veteran management to retain the stem and provide habitat.

<1 year Low

T131 Common

Lime M 15 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600


Moderate


access.


<1 year Low

T132 Common

Lime M 15 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600


Moderate


access.


<1 year Low

T134 Common

Lime M 15 4 4.5 4.5 4.5 4.5 Fair 20+ C2 600


Moderate


access.


<1 year Low

T135 Common

Lime M 20 4 9 7 7 7 Fair 20+ C2 800

Significant quantities of deadwood can be seen within the canopy. Crown distorted due to group pressure. Significant asymmetry to the canopy. Elongated branches visible within the canopy. Branches are predisposed to failure.

Moderate


access.

Remove large deadwood only. Retrench the canopy in stages to create a smaller canopy. Crown lift to 5.2m to enable vehicle access. Reduce canopy spread overall by 2m in the NE canopy. Reduce branches extending outside the canopy line by 1.5m. or Consider veteran management to retain the stem and provide habitat.

<1 year Low





Tag No. Species

Ag

e

He

igh

t

He

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t to

c

an

op

y

No

rth

So

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Ea

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Wes

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Sa

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Ca

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Ste

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(mm

)

Observations Risk

offered by tree

Target Assessment


Action

Risk offered

following Works

T136 Common

Lime M 20 4 6.5 6.5 6.5 6.5 Fair 20+ C2 800

Significant quantities of deadwood can be seen within the canopy. Cracking visible in branches in the outer canopy. Hazard beam can be seen within the canopy. Crown distorted due to group pressure. Significant asymmetry to the canopy. Elongated branches visible within the canopy. Branches are predisposed to failure.

Moderate


access.

Remove large deadwood only. Retrench the canopy in stages to create a smaller canopy by a maximum of 1.5m. Reduce branches extending outside the canopy line by 1.5m. Crown lift to 5.2m to enable vehicle access. or Consider veteran management to retain the stem and provide habitat.

<1 year Low

T139 Common

Lime M 12 4 5 5 5 5 Fair 10+ C2 800

Medium cavity visible within the main stem. Significant quantities of deadwood can be seen within the canopy. Crown distorted due to group pressure. Significant asymmetry to the canopy. Elongated branches visible within the canopy. Branches are predisposed to failure.

Moderate


access.

Remove large deadwood only. Retrench the canopy in stages to create a smaller canopy by a maximum of 1.5m. Reduce canopy overall by 2m limit branch end loading.2.5m to S. Consider veteran management to retain the stem and provide habitat. Crown lift to 5.2m to enable vehicle access.

<1 year Low

T144 Common

Lime M 20 4 6.5 6.5 6.5 6.5 Fair 20+ C2 900 Large deadwood can be seen in the outer canopy. Moderate


access.


<1 year Low

T146 Common



access.


<1 year Low

T147 Common



access.


<1 year Low

T149 Common



access.

Remove large deadwood only. Canopy remodelling to improve shape. Retrench the canopy in stages to create a smaller canopy. Crown lift to 5.2m to enable vehicle access.

<1 year Low

T151 Common

Lime OM 6 3 4 4 4 4 Fair 20+ C2 450


Moderate


access.


<1 year Low

T152 Common

Lime OM 11 3 4 4 4 4 Fair 20+ C2 500


Moderate


access.


<1 year Low

T156 Common

Lime M 17 3 5.5 5.5 5.5 5.5 Fair 20+ C2 600


Moderate


access.


<1 year Low





Tag No. Species

Ag

e

He

igh

t

He

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t to

c

an

op

y

No

rth

So

uth

Ea

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Wes

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Vit

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ty

Sa

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Ca

teg

ory

Ste

m D

ia

(mm

)

Observations Risk

offered by tree

Target Assessment


Action

Risk offered

following Works

T157 Common

Lime M 14 3 5.5 5.5 5.5 5.5 Fair 20+ C2 600


Moderate


access.


<1 year Low

T159 Common

Lime M 14 3 5.5 5.5 5.5 5.5 Fair 20+ C2 600

Large deadwood can be seen in the outer canopy. Significant epicormic shoots are visible throughout the canopy. Broken branches visible within the canopy. Canopy has been reduced (topped) & redeveloped.

Moderate


access.


<1 year Low

T160 Common

Lime M 20 3 6 6 6 6 Fair 20+ C2 700


Moderate


access.


<1 year Low

T161 Common

Lime M 14 3 5.5 5.5 5.5 5.5 Fair 20+ C2 600


Moderate


access.


<1 year Low




APPENDIX C – SITE PLAN

Orientation ( Estimated)

NORTH

Symbol Guide High Target Area Moderate Target Area Extreme Risk Tree High Risk Tree Moderate Risk Tree Low Risk Tree

Title: Tree Location Plan

Drawing No: BA5446/A

Date: 25/05/16

Drawn By: IB

Sale: Not to Scale. General NOTE: Thi plan should be v iewed in

COLOUR a monochrome copy should not be

relied upon, the plan should be v iewed in

conjunction with the Tree Assessment BA5446,

Available from Barnes and Associates.

Please do not scale form this drawing. All

dimensions should be checked on site, any

errors or divergences should be brought to the

attention of Barnes and Associates.

Copyright of Barnes & Associates. All right

described in Chapter IV of the Copyright,

Design & Patents Act 1988 have been

generally asserted © 25/05/2016. Copyright of

this plan remains with Barnes Associates until all

fees are paid in full.

Base image courtesy of © Google and third

party suppliers and based upon the Image

dated 25/05/2016.




A P P E N D I X D – F U R T H E R A S S E S S M E N T S Detailed below are the further assessments that have been identified during the initial site appraisal, these include both more detailed assessments to confirm the actual level of risk of trees highlighted in the report as well as the regular and seasonal assessment associated with normal site management. Urgent Further Assessment:

T 1 1 8

I d e a l l y - U n d e r t a k e T o m o g r a p h y o f n o t e d f a u l t . a t 3 . 5 m

< 6 M o n t h s

T 1 1 9

I d e a l l y - U n d e r t a k e T o m o g r a p h y o f n o t e d f a u l t . a t 4 m

< 6 M o n t h s

None Urgent Further Assessments:

T r e e s A f f e c t e d b y I v y

A s s e s s t h e c o n d i t i o n o f t h e s t e m a f t e r r e m o v i n g i v y . O n c e I v y h a s b e e n

c o n t r o l l e d

W h o l e s i t e

R e a s s e s s p e r i o d i c a l l y a n d p a r t i c u l a r l y a f t e r h i g h w i n d s . A d v i s o r y

Ongoing Assessment

R i s k A s s e s s m e n t

A s s e s s t h e a r e a s p o p u l a t e d b y T r e e s a n d t h e r i s k o f f e r e d b y t h e m t o s t r u c t u r e s a n d

s i t e u s e r s .

U n d e r t a k e o n a n 1 8 o r 3 0 m o n t h c y c l e a l t e r n a t i n g a s s e s s m e n t s b e t w e e n p e r i o d s w h e n t h e

t r e e s a r e i n a n d o u t o f l e a f .

A r b o r i c u l t u r a l

M a n a g e m e n t

P l a n

A s s e s s t h e t r e e s i n d e t a i l a n d i d e n t i f y b r o a d m a n a g e m e n t p r i n c i p a l s i n r e l a t i o n t o

t h e m a n a g e m e n t o f t r e e s .

U n d e r t a k e o n a f i v e c y c l e .




D E T A I L S O F F U R T H E R A S S E S S M E N T M E T H O D S .

We hope this information will help you choose the most appropriate assessment to meet your needs. Please find below a brief outline of methods that provide additional information in relation to tree safety. If you have any particular requirements in relation to your site then please feel free to discuss them with us, as we should be able to tailor information to suit your particular needs. INCREMENT BORE - After screwing the tube into the tree, an extractor is used to remove the wood core. The thickness of sound wood can be measured accurately. Increment borers provide good information but create a significant hole (up to 1cm or so) that can breach a trees internal defence mechanism, we typically only use this where there is a significant safety concern or as a last resort. RESISTOGRAPH - This measures the drilling resistance of a needle drill. Data can be displayed as a paper trace (shown opposite) or as a digital output for a more detailed assessment of the internal condition of the tree. Again this method can breach a trees internal defence mechanism and as a result we only use this method where there is strong suspicion of decay or to confirm other test results.

THERMAL IMAGING CAMERA (TI) - Produce images upon the amount of infrared energy emitted, transmitted, and reflected by an object. A thermal imaging camera will show subtle temperature changes when the tissues of the wood or bark are altered or destroyed by physical actions or pathogens in addition to identifying areas of restricted vascular activity or destroyed tissues below the surface. CHLOROPHYLL FLUORESCENCE – By measuring the capacity of a plant to carry out photochemistry this can provide a measure of health and identify impacts from a range of issues including stresses caused by environmental conditions. It is used as a means of detecting physiological damage caused by biotic or abiotic stress factors. The very nature of the technique ensures early detection of stress that could lead to decline well before visible symptoms manifest.

STRESS WAVE TIMER - Stress wave techniques are the equivalent of a single shot Tomograph. The time taken for a sound wave to travel across a known distance give an insight into the deterioration in wood structure. Deterioration in tree stems increases the time taken for the signal as the sound wave needs to travel around faults of decay or holes between the two sensors. The reference velocity depends on tree species.




STABILITY MODELLING – Key dimensional information is used to compute various factors in relation to tree stability, enabling determination and comparative evaluation of:

Tree wind load and centre of gravity.

Safety improvement following crown reduction.

Stability reduction by decay.

Tipping-stability reduction by root decay and/or trenching.

Enable safety-balancing between the retained stem cross-section and wind-load experienced by the tree.

This allows the determination of strength loss due to structural defects in the cross sections of stems and branches and anchorage plate losses in relation to canopy size and expected wind-loads. In addition, the method enables evaluation of load reduction by crown reduction pruning to further achieve higher safety in damaged trees. The inputs are based on observations rather than diagnostic instruments but enable accurate (if not as precise) estimations of safety which are sufficient for many tree assessment purposes. However, the precision of the evaluation can be increased by putting in results from proper sonic tomography or resistance drilling with density-calibrated devices. SONIC TOMOGRAPHY (SOT) - A non-invasive tool for assessing decay in trees – shown to the right. It works on the principle that sound waves passing through decay move more slowly than sound waves traversing solid wood. The Picus sonic tomogram sends sound waves from a number of points around a tree trunk to the same number of receiving points, the relative speed of the sound can be calculated, and a two-dimensional image of the cross-section of the tree, ‘a tomogram’, can be generated. Using the differences in the transit times between each pair of sensors, the Picus analysis software constructs a two-dimensional picture (acoustic tomogram), which show zones of differing sound transmission properties within the stem. These results can be combined with other scans in a 3D representation to provide a better understanding of the internal condition of the stem.

ELECTRICAL RESISTANCE TOMOGRAPHY (ERT) – This method gathers chemical information about the wood such as water and/or ion concentration and physical properties that provides information about the internal condition of the stem. Low resistivity can identify increased moisture content, whereas hollowed structures cause increases in resistance. After collecting all the measurements, the information is displayed in the form of a coloured distribution plan for analysis as shown opposite. Again, these results can be combined with other scans in a 3D representation to provide a better understanding of the internal condition of the stem. SWAY MONITORING - Sensors attached to the base of the tree enable us to test the root anchorage & stem stability. When wind blows trees start to sway and this load is transmitted into the ground via the stem and rootplate - transferred to the root plate. We use sensors to record sway motion of trees in natural winds. The motion of the tree shows the real response of a tree to the natural conditions and enable identification of excessive movement and helps identify weak trees.




STATIC PULLING TEST - The tree-pulling test provides information about the breaking stability of the trunk and the stability of the roots. It is used to assess a tree’s stability with regard to stem fracture and uprooting precisely and non-invasively.

In a pulling test, a load (substituting for the wind) is exerted on a tree using a winch and a steel cable. The reaction of the stressed tree under this defined load is measured with high resolution devices (elastometer and inclinometer), and the data obtained are compared with those of sound trees. The major components to be considered in such calculations are the wind-load (the surface of the load-bearing structure, tree height, etc.) and the material properties of green wood.

Please see the table below, which provides a comparison of the methods used in advanced tree assessment and their suitability to assessing particular features and an indication of relative cost. If you have any particular requirements in relation to your site or require a combination of assessment of your trees please feel free to discuss them with us, as we should be able to tailor information to suit your particular needs and would be happy to provide a fixed price quote.

Comparison of methods in advanced tree assessment

Blue ● Good Yellow ● Fair Red ● Unfavourable

Adapted from Roloff (2016)

Tipping Safety

Fracture Safety

Tree Vitality

Damage to Tree

Cost per test

Increment Bore ● ● ● ● Low

Resistograph ● ● ● ●

Thermal Imaging Camera ● ● ● ●

Chlorophyll Fluorescence ● ● ● ●

Stress Wave Timer ● ● ● ●

Stability Modelling ● ● ● ●

Sonic Tomography ● ● ● ●

Electrical Resistance Tomography ● ● ● ●

Sway Monitoring ● ● ● ●

Static Pulling Test ● ● ● ● High




A P P E N D I X E – T R E E S & R I S K Tree owners should take a balanced and proportionate approach to tree management It is recognised that trees are managed for a variety of reasons and therefore that the expectation of a “suitable and sufficient risk assessment” referred to by the HSE varies with context. In general, the risk from trees has certainly reached the situation where residual risks (those that remain after management for safety) are sufficiently low that investment in additional measures is likely to be disproportionate to any safety benefi t. As the HSE itself notes in Reducing risks, protecting people:

“Any informed discussion quickly raises ethical, social, economic and scientific considerations, for example: … how to achieve the necessary trade-offs between benefits to society and ensuring that individuals are adequately protected; the need to avoid the imposition of unnecessary restrictions on the freedom of the individual.”

Extremely low risk of harm HSE guidance for its inspectors and local authority enforcement officers on the standard of tree risk management and the DARM research commissioned by the NTSG on behalf of landowners confirm that the overall real risk of serious harm from trees in the UK is “extremely low”. Indeed, the levels of risk are so low that they are “comparable to those that people regard as insignificant or trivial in their daily lives”, near the bottom of the spectrum of what the HSE considers as an acceptable risk:

“Risks falling into this region are generally regarded as insignificant and adequately controlled. We, as regulators, would not usually require further action to reduce risks unless reasonably practicable measures are available. The levels of risk characterising this region are comparable to those that people regard as insignificant or trivial in their daily lives. They are typical of the risk from activities that are inherently not very hazardous or from hazardous activities that can be, and are, readily controlled to produce very low risks.”

Reasonable risk management generally aims to provide trees that can be regarded stable in a normal / foreseeable, regularly experienced storm event in relation to the situation / context of the tree. In this region, this is reasonable to assume a ‘Storm’ of force 10 using the Beaufort Scale (55 - 63 miles per hour) of wind speeds on land will occur annually. It should be realised that all trees do pose a risk; recent work in Germany has shown even sound trees that would typically be regarded as safe can fail during high winds through various factors relating to wood physiology, dynamics and the relationship between the root system and the supporting soils. It should be remembered that for any given tree regardless of its stability, there will always be a wind load that has the potential to break or uproot a tree regardless of its condition. Typically, trees have evolved to fail in part, i.e. twigs and branches are sacrificed / fail from a parent tree rather than the tree being lost entirely. Observations at various sites in this country have found that twigs and branches, can break from trees at wind speeds of as little as 31 miles per hour, the upper limit of a ‘strong breeze’ as detailed in Beaufort Scale 6 (25 - 31 miles per hour). This has led to a recommendation for certain sites with grounds open to the public, being closed when the wind speeds approaching 'Near Gale' or Force 7, as detailed by the Beaufort Scale (32-38 miles per hour). Such failures are difficult to predict with any great level of detail and a general position is best adopted. Typically, the level of risk offered by trees will be significantly greater as the force of the wind increases, the threat from aerial parts i .e. deadwood, tight unions and elongated branches may remain even following remedial works. Typically, branch failures are likely to be limited to small diameter branches and to periods of extreme weather, though as often seen in any natural model, exceptions to the rule can be expected. Therefore, in managing trees we are aiming to limit or reduce the risk to nearby features, unfortunately it is not possible to remove the risk offered by a tree entirely. As an arborist, I am a tree specialist and use my knowledge, education, training and experience to examine trees, to recommend measures to enhance their beauty and health, and attempt to reduce the risk of living near trees. As a client, you may choose to accept or disregard these recommendations, or seek additional advice. As an arborist, I cannot detect every condition that could possibly lead to a tree or limb failure. Trees are living organisms that may fail in many ways, some of which we do not fully understand. Conditions are often hidden within the tree and below the ground. As arborists, we cannot guarantee that a tree will be healthy or safe under all circumstances, or for a specified period, of time. Sometimes trees may appear "healthy," but may be structurally unsound. Likewise, remedial treatment, like any medicine, cannot be guaranteed. Treatment, pruning and removal of trees may involve considerations beyond the arboricultural perspective, such as property boundaries and ownership, disputes between neighbours, planning issues, sight lines, landlord-tenant matters etc. Arborists cannot take such issues into account unless complete and accurate information is given to them. Likewise, as an arborist, I cannot accept any responsibility for the authorization or non-authorization of any recommended treatment or remedial measure. Furthermore, certain trees are borderline cases as to whether they should remain or be removed. Also, co nditions change, and a tree may need further monitoring in the future to determine its health and structure.

Even healthy trees unaffected by defects can fail in extreme weather conditions. Trees can be managed, but they cannot be controlled, and to live near a tree is to accept some degree of risk.

Barne Barnes & Associates, Rivermead, Skelton Road, Langthorpe, North Yorkshire, YO51 9BZ

Telephone: 01423 322 371 Fax: 01423 322 371 Mobile: 07831 530 563

Em Email:[email protected]

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Tree Surveys & Condition Reports

Tree Health & Safety Reports

Tree Risk Assessments

Tree Population Site Inventories

Estate Tree Management

Woodland Management

Tree Work Specification & Tenders

Insurance & Mortgage Reports

Decay Detection & Mapping – Picus

Windload & Stability Assessments

Development Site Tree Reports to BS5837

Arboricultural Implication Assessments (AIA)

Arboricultural Method Statements (AMS)

Construction Exclusion Zone Management

Tree Protection Plan Design

Tree Valuation & Replacement Costing

TPO Objections & Appeals

Tree planting Schemes

Landscape visual impact assessment

Landscape architecture

mailto:[email protected]

Documents

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