Think Trees Arboricultural Consultancy & Tree Care Client: Mr & Mrs G

Pre-Development Arboricultural Report

The Monks Walk, Half Acres, Bishop’s Stortford – 27 MAY 2019

think trees arboricultural consultancy & tree care Client: Mr & Mrs G. Griffiths Contact: Gary Griffiths Site: The Monks Walk, Bishop’s Stortford Prepared by: Paul Melarange BSc (Hons) M.Arbor.A Date 27 May 2019 Version 02

Thinktrees Ltd has prepared this document in accordance with the instructions of its clients, Mr & Mrs Griffiths, for their sole and specific use. Any other persons who use any information contained herein do so at their own risk. 1

Thinktrees Ltd has been instructed by Mr G. Griffiths, to inspect the significant trees that may be affected by proposals to develop the property at The Monks Walk, Half Acres, Bishop’s Stortford, and to produce a pre-development arboricultural report in accordance with BS 5837:2012. A site visit was carried out on 20 June 2018.

Eighteen individual trees and one group were inspected as part of the survey. The species, size and condition of the trees are listed in the schedule included as Appendix 1. Plans 1 and 2 show the existing and proposed site layouts respectively, the location of the trees, their canopies and root protection areas (RPAs) calculated using the guidance contained in the British Standard: Trees in relation to design, demolition and construction – Recommendations (BS 5837:2012).

From Plan 2 it can be seen that 2 individual trees will need to be removed to enable the development. Although they are not within the footprint of the proposed building, they are in such close proxity that it will not feasible to retain them. Group 8, which comprises 8 semi-mature holly, will also need to be removed as it is within the footprint of the proposed building.

Tree protection fencing will be required to prevent damage occuring to the remaining trees during the construction phase of the project. The layout of the fencing is shown in the Tree Protection Plan.

It is feasible to implement the proposed development, which forms the subject of this report, without having a significant effect on the health of those trees that are to be retained. However, this will only be achieved if the advice and recommendations detailed in this report are followed.

2 Contents

1 Preface...... 4 1.1 Instruction...... 4 1.2 Documents and information provided...... 4 1.3 The proposals...... 4 1.4 Site visit...... 4 1.5 Brief site description...... 4 1.6 Tree observations...... 4 1.7 Limitations...... 4

2 Introduction...... 5 2.1 Trees and planning...... 5 2.2 British Standard 5837:2012...... 5 2.3 Scope of this document...... 5

3 Statutory Tree Protection...... 5

4 Tree Constraints...... 6 4.1 The retention categories of the trees...... 6 4.2 Above-ground constraints...... 8 4.3 Below-ground constraints...... 8

5 Arboricultural Impact Assessment...... 10 5.1 The proposals...... 10 5.2 Arboricultural impact of the development...... 10 5.3 Trees 1, 2 & 3...... 11 5.4 Trees 6, 7 & Group 8...... 11 3 5.5 Tree 11...... 11 5.6 Storage of plant and materials...... 12 5.7 Services...... 12

6 Recommendations...... 14 6.1 Specific recommendations...... 14 6.2 General precautions...... 14 6.3 Tree surgery...... 14 6.4 Removal of vegetation...... 14 6.5 Monitoring...... 14 Appendices Appendix 1 Tree Schedule

Appendix 2 Default specification for protective barrier

Appendix 3 Plan 1 Tree Constraints Plan (Existing) Plan 2 Tree Constraints Plan (Proposed) Plan 3 Preliminary Tree Protection Plan 1 Preface

1.1 Instruction Thinktrees Ltd has been instructed by Mr G. Griffiths, to inspect the significant trees that may be affected by proposals to develop the property at The Monks Walk, Half Acres, Bishop’s Stortford, and to produce a pre-development arboricultural report in accordance with BS 5837:2012.

1.2 Documents and information provided Mr Paul Young (Architect) provided a digital topographical survey plan of the site and CAD drawings of the proposed development.

1.3 The proposals It is proposed to constuct a detached dwelling on the South side of the property.

1.4 Site visit The site visit was carried out on 20 June 2018. All observations were from ground level without detailed investigations and all dimensions were estimated unless otherwise indicated. The weather at the time of inspection was clear, still and dry, with good visibility.

1.5 Brief site description The site, which lies within the Bishop’s Stortford Conservation Area, comprises a large detached residential property and smaller outbuilding. The property has generous formal gardens to the front and boundaries comprising predominantly mature trees of a variety of species. The site is bounded on all sides by residential properties.

1.6 Tree observations A visual inspection was made of the trees. Appendix 1 contains information on their species, dimensions and condition.

1.7 Limitations This report is concerned only with assessing the condition of the trees and whether or not they may be affected by the proposals to develop the site. 4

This report takes no account of whether the trees could affect the soil in the area in such a way as to cause the proposed development, or other buildings, to suffer tree-related subsidence or heave damage.

This report is based on the documents listed in Section 1.2 and the information collected during the site visit.

This report doesn’t take into account potential extreme climatic events not normally expected in this locality. Such events could include, but aren’t restricted to, severe windstorms, floods or drought. In addition, this report doesn’t take into account potential outbreaks of pests or diseases.

Operations carried out in the vicinity of the trees, either in the past or future, could affect their health and stability; such operations could include, but aren’t restricted to, trenches dug for the installation or repair of utilities. No decay detection equipment was used to help gather the data used in this report. 2 Introduction

2.1 Trees and planning Under the UK planning system, local authorities have a statutory duty to consider the protection and planting of trees when granting planning permission for proposed development. The potential effect of development on trees, whether statutorily protected (e.g. by a tree preservation order or by their inclusion within a conservation area) or not, is a material consideration that is taken into account in dealing with planning applications.

2.2 British Standard 5837:2012 British Standard 5837:2012 gives recommendations and guidance on the relationship between trees and design, demolition and construction processes, the aim of which is to achieve a harmonious and sustainable relationship between trees and structures.

2.3 Scope of this document This document provides details of the constraints posed by the trees. It also includes an arboricultural impact assessment that evalues the direct and indirect effects of the proposed design and where necessary recommends mitigation.

3 Statutory Tree Protection

East Herts District Council’s online mapping facility, accessed on 20/07/18, indicates that the property which forms the subject of this report is within the Bishop’s Stortford conservation area.

The Town and Country Planning Act 1990 makes special provision for trees in conservation areas which are not the subject of a Tree Preservation Order (TPO). Under section 211 anyone proposing to cut down or carry out tree work on a tree in a conservation area is required to give the LPA six weeks’ prior notice (a ‘section 211 notice’). The purpose of this requirement is to the give the LPA an opportunity to consider whether a TPO should be 5 made in respect of the tree. 4 Tree Constraints

4.1 The retention categories of the trees Each of the individual trees, groups of trees and/or woodlands have been assessed for their quality and benefits within the context of proposed development. The quality of each tree or group of trees has been recorded by allocating it to one of four retention categories (see below). Specific details for each tree and group, including their retention category, are listed in the schedule included as Appendix 1 and shown on the ‘Tree Constraints Plan’ by the colours used to depict them.

CATEGORY COLOUR CONSTRAINTS/OPPORTUNITIES

A Green A tree or group of high quality and value that should only be considered for removal in exceptional circumstances.

B Blue A tree or group of moderate quality and value that should be retained where possible.

C Grey A tree or group of low quality and value that could be retained but should not be considered a constraint to development.

U Red A tree or group in such a condition that they cannot realistically be retained as living trees in the context of the current land use for longer 6 than 10 years. However, category U trees can have existing or potential conservation value which it might be desirable to preserve.

The number of trees and groups in each category are shown in the graphs on the next page. 12

6 No. of Trees No. of 4

0 A B C U Category

Figure 1. Number of individual trees in each retention category

Figure 1. Number of individual trees in each retention category. 1.2

0.8

0.6 7 No. of Groups No. of 0.4

0.2

0 A B C U Category

Figure 2. Number of groups in each retention category. 4.2 Above-ground constraints The crowns of retained trees impose an above-ground constraint. Above-ground constraints might also arise from the following attributes:

1. the current and ultimate height and spread of the tree; 2. species characteristics, including evergreen or deciduous, density of foliage, and factors such as susceptibility of honeydew drip, branch drop, fruit fall, etc.

The current crown spread for each of the trees is shown on the ‘Tree Constraints Plan’ (Appendix 3). In addition to the current crown spread it is prudent, where feasible, to provide a gap of at least 1m between the outer-edge of the crown of a mature tree and a proposed structure to allow for future growth. This gap should be increased for trees with a high future growth potential i.e. trees that are young or early-mature.

Trees in close proximity to buildings can create problems associated with shade and loss of light. This is particularly a problem where there are rooms that require natural light.

Direct damage to structures can occur as a result of continuous whipping of branches against the fabric of a building. Structures should therefore be designed and/or located with due consideration for a tree’s ultimate growth, so as to reduce the need for frequent remedial pruning or maintenance. Failure to consider these issues can result in pressure for the removal of trees post-development.

Figure 3. Illustration showing the above and below ground constraints.

4.3 Below ground constraints The majority of tree roots are located within the upper 600mm of soil, and often extend well beyond the extent of the crown. The soil around a tree acts as a source of water and nutrients, which is exploited by the roots. It also provides the anchorage which is essential for tree stability. The minimum area of soil required to maintain a healthy and stable tree is referred to as the ‘Root Protection Area’ (RPA), and should be considered a constraint to development should the tree be retained.

For single-stemmed trees the RPA is equal to the area of a circle with a radius twelve times the diameter of the trunk measured 1.5m above the ground. For multi-stemmed trees the RPA is equal to the area of a circle with a radius equal to the combined mean diameter of all the stems. In addition to the RPA, it is prudent to allow for an area that extends at least 1m beyond the perimeter of the RPA as a construction buffer zone. This is to allow for construction activity which is often necessary outside the footprint of the proposed development. This includes activities such as the excavation of foundations and the installation of services or drainage.

9 5 Arboricultural Impact Assessment/ Arboricultural Method Statement

5.1 The Proposals It is proposed to constuct a detached dwelling on the South side of the property.

5.2 Arboricultural impact of the development Two individual trees and 1 group will need be removed to enable the development (see graph below).

A No. of Trees 6 B C U

0 Total Surveyed Retained Removed

Figure 4. The number of trees in each retention category that are to be removed or retained.

1.2 10

0.8

A No. of Groups 0.6 B C U

0.4

0.2

0 Total Surveyed Retained Removed

Figure 5. The number of groups in each retention category that are to be removed or retained. 5.3 Trees 1, 2 & 3 Trees 1, 2 and 3 (Figure 6) are all mature yew (Taxus baccata) located near to the southern boundary. The trees are in such close proximity to each other that they function as a cohesive group. They are clearly visible from outside the property and provide a significant level of screening. Therefore, these trees are to be retained and suitably protected througout the development process. Tree protection fencing is to be positioned so as to protect not only the RPAs of these trees, but also the wider rooting area to the east and west.

Figure 6. Trees 1, 2 & 3 (arrowed) viewed from the northwest.

5.4 Trees 6, 7 & Group 8 11 Tree 6 (a mature holly) and Tree 7 (a mature box elder) are in such close proxity to the proposed building that it will not be feasible to retain them. Group 8 (which comprises 8 semi-mature holly - Figure 7) will also need to be removed as it is within the footprint of the proposed building. All of these trees are located centrally within the site and have limited visibility from the public realm. Their removal is unlikely to have an impact on public amenity or screening.

5.5 Tree 11 The footprint of the proposed building is approximately 1m beyond the RPA of Tree 11 (a Purple sycamore - Figure 7). Tree protection fencing is to be erected approximately 1.5m from the proposed building, which slightly encroaches the RPA. The reason for this is to enable the erection of scaffolding during the construction phase. Such a minimal amount of encroachment into the RPA is unlikely to have a detrimental effect on the health or stability of the tree. Figure 7. Tree 11 and Group 8.

5.6 Storage of plant and materials In order to ensure that the trees are suitably protected throughout the project, tree protection fencing is to be erected in close proximity to the proposed building. This will limit significantly the amount of space in which materials, plant and machinery can be stored. Therefore, it proposed that an area of hard standing adjacent to the existing house (Figure 8) is used for this purpose.

Figure 8. Separate materials storage area (arrowed).

5.7 Services Information regarding the location of the existing and proposed services has not been provided. Therefore, specific recommendations as to the installation of services/utilities/ drainage have not been included in the Arboricultural Method Statement (AMS). It is recommended that these details be provided prior to the commencement of development to ensure that their installation does adversely affect the retained trees. 6 Recommendations

6.1 Specific recommendations

• Trees 6 and 7 and Group 8 will need to be removed to enable the development.

• The remaining trees are to be retained and suitably protected using tree protection fencing. This is to be constructed as per the default specification (Figure 2 - Appendix 2). The default specification consists of a vertical and horizontal scaffold framework, well braced to resist impacts. The vertical tubes should be spaced at a maximum interval of 3m and driven securely into the ground. Onto this framework, welded mesh panels should be securely fixed.

6.2 General precautions The following general precautions should also be taken during the construction phase.

• No materials or fuel should be stored close to or within the RPAs of trees to be retained or where new trees are to be established.

• There should be no bonfires within 10m of the outer edge of the crown or RPA of a tree to be retained.

• Mechanical equipment shouldn’t be refuelled within the RPAs of retained trees or areas where new trees are to be established.

• No cement should be mixed or stored within the RPAs of retained trees or areas where new trees are to be established.

• Cement mixers shouldn’t be washed within or uphill of the RPAs of retained trees or areas where new trees are to be established.

• The soil level within the RPA of a retained tree should not be raised or lowered 13 without the agreement of an arboricultural consultant or the local authority Tree Officer.

• No plant should be operated within the RPAs of retained trees unless the soil is suitably protected against compaction.

• Excavation should not take place within the RPAs of retained trees unless an arboricultural consultant or the local authority Tree Officer is supervising the work.

• The guidance contained within the National Joint Utilities Group Volume 4 (Guidelines For The Planning, Installation And Maintenance Of Utility Apparatus In Proximity To Trees (Issue 2, 2007); http://www.njug.org.uk/ accessed 12/4/10) should be followed when installing underground services within the RPAs of retained trees.

• Surface water run-off should not be redirected into or out of the RPA of a retained tree.

• No materials should be dumped within the RPA of a tree, whether in a skip or on the ground. • No vehicles should be parked or operate within the RPA of a retained tree.

6.3 Tree surgery Any work carried out on the trees should be done by a suitably qualified and insured arborist. Work should be undertaken in accordance with BS3998:2010 (Tree work- recommendations).

6.4 Removal of vegetation Vegetation such as laurel hedging and large shrubs will need to be removed to facilitate the development and to enable movement across the site. Any removal of vegetation from within the construction exclusion zone (i.e. within the tree protection fencing) must be carried out by hand i.e. using a chainsaw to cut vegetation down to ground level. If stumps are to be removed from within these areas, this should be done using a stump grinder rather than a digger to reduce the risk of damage to the roots of those trees to be retained. This is particularly relevant to the removal of Tree 6.

6.5 Monitoring A pre-commencement meeting with a tree officer, the project arboriculturist, the building contractor and the client is required. This will ensure that all the methods and procedures detailed in this document are understood and implemented.

In addition to the above, the project arboriculturist is to make fortnightly site visits for the duration of the project to confirm that the protection measures agreed and employed are functional and achieving their purpose, and to liaise with the LPA’s tree officer to agree any changes or revisions that may be necessary before they are implemented.

An email confirming that the methods and procedures detailed in this document have been adhered to, will be sent to the LPA’s tree officer following the completion of each stage of the project.

14 Appendix 1

15 BS5837 Tree Schedule

The Monks Walk, Half Acres

Condition Notes 2 Species CROWN SPREAD (m) Preliminary recommendations Priority

N NE E SE S SW W NW Age class Structural Condition RPR (m) Remaining Contribution (years) Tree/Group Number No. of Trees Height (m) Average Stem diameter (cm) No. of Stems Age class RPA (m ) BS Category Crown Cleanrance (m) Physiological Condition T 1 1 Taxus baccata 14.5 42 1 2.4 4.8 4.0 1.9 1.0 Mature Fair Good Epicormic growth - Base / bole / principal stems. This tree forms part of a 5.079.840+ B2 Yew group canopy. Co-dominant stems - the junction of which is at approximately 1.8m and is of the wide-mouthed bark inclusion type with no discernible bulging (stable at time of inspection). There is a second bifurcation - the junction of which is at approximately 4.5m and is of the wide-mouthed bark inclusion type with no discernible bulging (stable at time of inspection) - rubbing branches in strong physical contact with each other above the junction -limiting movement of the co-dominant stems. These have the potential to fuse, creating a natural brace, however if these branches die or fail it could increase the likelihood of the junction failing.

T 2 1 Taxus baccata 14.0 39 2 6.8 6.0 2.5 1.9 1.9 Mature Good Good Epicormic growth - Bole / principal stems. Unbalanced crown - Minor. 4.770.440+ B2 Yew Tree forms part of a group canopy.

T 3 1 Taxus baccata 16.0 55 1 7.6 1.8 5.5 6.5 1.8 Mature Good Good Epicormic growth - Bole / principal stems. Ivy or climbing plant. 6.6136.840+ B2 Yew Leaning trunk -Minor. Unbalanced crown - Minor. Tree forms part of a group canopy.

T 4 1 Picea abies 13.5 42 1 4.8 4.5 3.8 4.0 2.2 Mature Fair Good Arboricultural work - Historic. Crown reduction - Historic. Off site 5.079.840+ B1 Norway Spruce tree.

NB. Stem diameter green estimated value The Monks Walk, Half Acres

Condition Notes 2 Species CROWN SPREAD (m) Preliminary recommendations Priority

T 6 1 Ilex aquifolium 12.0 31 1 3.0 3.3 3.1 2.0 0.1 Mature Good Good Base / stems obscured - Vegetation. Ivy or climbing plant. 3.743.540+ B1 Holly Tree is located centrally within the property and is not clearly visible from outside the site. Consequently its contribution to the landscape character is minimal. Fell - ground level - to enable development Not set T 7 1 Acer negundo 9.0 25 1 2.0 1.5 2.0 3.0 3.0 Mature Poor Poor Competition -Adjacent trees. Pruning wounds - Historic. There are 3.028.310-20 U Box Elder (Ash - Leaved) fruiting bodies consistent with those of the fungus Cerioporus squamosus Maple at the base of the main stem. Tree is located centrally within the property and is not clearly visible from outside the site. Consequently its contribution to the landscape character is minimal. Fell - ground level - to enable development Not set

G 8 8 Ilex aquifolium 4.0 10 1 1.5 1.5 1.5 1.5 0.1 Semi Fair Good Group provides little visual amenity. Its contribution to the landscape 1.24.520-40 C2 Holly Mature character is minimal.

Fell - ground level - to enable development Not set

T 9 1 Taxus baccata 4.5 15 1 2.0 2.0 4.0 1.0 1.5 Early Fair Good Unbalanced crown - Minor. 1.810.240+ C1 Yew Mature

T 10 1 Laburnum anagyroides 6.0 17 2 5.7 1.8 6.0 3.0 2.0 Mature Poor Fair Competition -Adjacent trees. 2.013.110-20 C1 Common Laburnum (Golden Chain)

NB. Stem diameter green estimated value The Monks Walk, Half Acres

Condition Notes 2 Species CROWN SPREAD (m) Preliminary recommendations Priority

T 12 1 Pseudotsuga menziesii 20.0 56 1 4.8 6.0 4.5 4.5 2.0 Mature Good Good No significant faults observed. 6.7141.940+ B1 Douglas Fir

T 13 1 Robinia pseudoacacia 15.0 47 2 1.0 4.0 7.4 5.7 5.0 Mature Fair Fair Deadwood - Minor. Unbalanced crown - Minor. The is a structural branch 5.7102.120-40 B2 False Acacia sp./Black Locust with a cup-shaped union (no discernible bulging) at approximately 1.4m.

T 14 1 Taxus baccata 9.0 40 2 5.8 4.5 4.5 4.2 1.5 Mature Good Fair Base / stems obscured - Vegetation. Ivy or climbing plant. Co- 4.872.440+ B1 Yew dominant stems - the junction of which is at approximately 2.5m and is of the wide-mouthed bark inclusion type with no discernible bulging (stable at time of inspection).

T 15 1 Corylus avellana 4.0 17 20 2.2 2.2 2.2 1.4 0.5 Early Good Good Coppice stool -Regrown. 2.114.520-40 C1 Common Hazel Mature

NB. Stem diameter green estimated value The Monks Walk, Half Acres

Condition Notes 2 Species CROWN SPREAD (m) Preliminary recommendations Priority

T 17 1 Crataegus sp. 5.0 9 1 4.0 0.5 0.5 2.0 1.5 Mature Fair Fair Competition -Adjacent trees. Ivy or climbing plant. Suppressed 1.13.710-20 C1 Hawthorn sp. crown - Major. Unbalanced crown - Major.

T 18 1 Chamaecyparis sp. 8.0 11 1 0.7 0.7 0.7 0.7 4.0 Early Poor Fair Deadwood -Minor. Form - Attenuated stem / stems. 1.35.50-10 U False Cypress Mature

T 19 1 Taxus baccata 16.0 60 2 7.0 4.0 5.8 6.5 3.0 Mature Good Good Poor past pruning. Off site tree. 7.2165.140+ B1 Yew

NB. Stem diameter green estimated value

Table 1 of BS5837 (2012) Cascade chart for tree quality assessment

Category and definition Criteria (including subcategories where appropriate) Identification on plan Trees unsuitable for retention (see note)

Category U * 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 category U trees (e.g. where, for whatever RED reason, the loss of companion shelter cannot be mitigated by pruning) Those in such a condition that they cannot * Trees that are dead or are showing signs of significant, immediate, and irreversible overall decline realistically be retained as living trees in the * Trees infected with pathogens of significance to health and/or safety of other trees nearby, or very low quality context of the current land use for longer than 10 trees suppressing adjacent trees of better quality years NOTE Category U trees can have existing or potential conservation value which it might be desirable to preserve; see 4.5.7 1 Mainly arboricultural qualities 2 Mainly landscape qualities 3 Mainly cultural values, including conservation Trees to be considered for retention Category A Tree that are particularly good Trees, groups or woodlands of Trees, groups or woodlands of examples of their species, especially particular visual importance as significant conservation, GREEN Trees of high quality if rare or unusual; or those that are arboricutural and/or landscape historical, commemorative or with an estimated remaining life expectancy essential components of groups or features other value (e.g. veteran trees or of at least 40 years formal or semi-formal arboricultural wood-pasture) features (e.g. the dominant and/or principal trees within an avenue) Category B Trees that might be included in Trees present in numbers, usually Trees with material conservation category A, but are downgraded growing as groups or woodlands, or other cultural value BLUE Trees of moderate quality because of impaired condition (e.g. such that they attract a higher with an estimated remaining life expectancy presence of significant though collective rating than they might of at least 20 years remediable defects, including as individuals; or trees occurring unsympathetic past management as collectives but situated so as to and storm damage), such that they make little visual contribution to are unlikely to be suitable for the wider locality retention for beyond 40 years; or trees lacking the special quality necessary to merit the category A designation Category C Unremarkable trees of very limited Trees present in groups or Trees with no material merit or such impaired condition woodlands, but without this conservation or other cultural GREY Trees of low quality that they do not qualify in higher conferring on them significantly value with an estimated remaining life expectancy categories greater collective landscape value; of at least 10 years, or young trees with a stem and/or trees offering low or only diameter below 150 mm temporary/transient landscape benefits Appendix 2

21 BRITISH STANDARD BS 5837:2012

Appendix 3