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BDW SOUTHERN COUNTIES LTD
PROPOSED RESIDENTIAL DEVELOPMENT IFIELD COMMUNITY COLLEGE
CRAWLEY
Arboricultural Impact Assessment
June 2015 8842_AIA.001
COPYRIGHT
The copyright of this document
remains with Aspect Arboriculture Ltd.
The contents of this document
therefore must not be copied or
reproduced in whole or in part
for any purpose without the
written consent of
Aspect Arboriculture Ltd.
Aspect Arboriculture Ltd Hardwick Business Park
Noral Way Banbury
Oxfordshire OX16 2AF
t 01295 276066 f 01295 265072
e [email protected] w www.aspect-arbor.com
June 2015 8842_AIA.001
CONTENTS
1. INTRODUCTION 1
2. POLICY CONSIDERATIONS 3
3. STATUTORY DESIGNATIONS RELATING TO ARBORICULTURE 5
4. BASELINE INFORMATION 7
5. TREE CONSTRAINTS 8
6. IMPACT ASSESSMENT 12
7. CONCLUSIONS 18
8. RECOMMENDATIONS 19
APPENDICES
SURVEY BOUNDARY PLAN APPENDIX A
TREE SURVEY SCHEDULE APPENDIX B
TREE PRESERVATION ORDER PLAN APPENDIX C
TREE CONSTRAINTS PLAN APPENDIX D
PRELIMINARY TREE PROTECTION PLAN APPENDIX E
TREE SURVEY METHODOLOGY APPENDIX F
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1 INTRODUCTION
1.1 Instruction
1.1.1 Aspect Arboriculture has been commissioned to prepare an Arboricultural Impact
Assessment (AIA) to supplement BDW Southern Counties’ planning application for
residential development at the former Ifield Community College site, Crawley.
1.1.2 The proposals put forward relate to: Erection of 193 units (77 houses, 2 maisonettes,
7 Coachouses and 107 apartments), together with associated car parking, open
space, landscaping and vehicular access from the existing junction on Lady Margaret
Road.
1.2 Scope
1.2.1 This work provides an appraisal of the relationship between the application area’s
existing trees and the development proposals. In line with current industry advice, the
arboricultural information presented herein has been guided by the recommendations
within British Standard document BS5837:2012 ‘Trees in Relation to Design,
Demolition and Construction’.
1.3 Site Description
1.3.1 The site is located within West Crawley and comprises an irregular parcel of land
bound by existing residential development to the north, west and south and areas of
maintained recreational ground to the east (refer to Appendix A). Following
demolition of former college facilities in 2006, the site interior now consists of a matrix
of defunct hard surfaces and scrub colonisation.
1.3.2 The site is influenced by a number of mature Oaks, considered to be remnants of
former parkland, set amongst younger trees left over from previous soft landscaping
arrangements and residential boundaries. With the exception of the western
boundary which is void of onsite tree cover, the trees are distributed across the site
as a mixture of outlying standards and those set within established boundary
hedgerows.
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1.4 Limitations
1.4.1 This assessment has been prepared in respect of proposed development and should
not be interpreted as a report on tree health and safety. Reasonable effort has been
made to identify visible defects whilst undertaking the tree survey; trees are however,
prone to natural failure without warning therefore no guarantee can be made as to the
absolute safety of any of the trees surveyed. Aspect’s opinion of tree condition and
structural potential is therefore valid for a limited period of 12 months from the date of
inspection. Validity is assumed in the absence of inclement weather and no change
to the trees existing context.
1.4.2 This work relates to arboriculture, therefore reliance should not be given to comments
made in respect of other disciplines i.e. landscape, ecology or civil engineering
without first consulting an appropriate expert.
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2 LOCAL POLICY CONSIDERATIONS
2.1 Administration
2.1.1 The site occurs within the administrative boundary of Crawley Borough Council
(CBC). In terms of development control, the Council has a statutory obligation to
ensure adequate provision is made for the preservation of trees through Section 197
of the Town and Country Planning Act (1990). In response to this requirement, the
Council has prepared specific standards and policies which include trees within their
primary development control documents; understood to be the Core Strategy and
saved polices of the Crawley Local Plan (2000).
2.1.2 A review of this information has been undertaken to assist reaching balanced
conclusions regarding the significance of the site’s existing trees, and the influence
upon them arising from the proposals put forward.
2.2 Crawley Borough Local Development Framework Core Strategy (October 2008)
2.2.1 Trees are considered implicitly as natural features, wherein the Council recognises
the important contribution that trees make to the amenity of urban and rural areas; a
distinction is made for the desire to retain aged and veterans trees in particular.
2.3 Crawley Local Plan (2000)
2.3.1 Policy BN20 Landscape: In the context of proposed development, there is
presumption in favour of tree retention pursuant to which the applicant is expected to
identify and retain important tree cover. Although there is a presumption against the
clearance of trees and particularly woodland, the Local plan does not preclude the
removal of trees to enable development. The removal of trees is permitted if it can be
demonstrated that the proposed development will provide opportunities to enhance
local landscape and be of value to nature conservation. The provision of a
comprehensive replanting scheme is therefore a requisite expectation where tree
removal is necessary as part of development.
2.3.2 “Proposals for development will not normally be permitted if it will adversely affect
important natural landscape features, including woodlands, water courses and
adjacent land, trees and hedgerows. If development is permitted, the replacement of
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landscape features lost may be required (see Policy GD5). The Borough Council will
undertake and encourage improvements to the amenity and recreational value of
these areas”.
2.4 Policy BN21 Tree Preservation Orders:
As part of the Councils strategy for considering trees in the context of development,
the council may choose to make Tree Preservation Orders. The council will resist
proposals that threaten the loss of trees covered by a TPO, particularly where the
trees make a particularly important contribution to amenity of a site and it’s setting.
2.4.1 “Where an application is necessary for the removal of a tree protected by a Tree
Preservation Order (T.P.O), permission will only be granted if the tree is unhealthy or
dangerous, or if it no longer contributes to public amenity. The planting of
replacement trees may be required. Work on trees protected by T.P.O.s may be
permitted if it does not detract from the health or appearance of the tree”.
2.5 Policy BN1 Conservation Areas: When considering safeguarding the character or
appearance of areas considered to be of special interest, the Council include trees
within the list of criteria to take into account (refer to criterion iii, “the quality of open
spaces, trees and other landscape features”.
2.6 Comment
2.6.1 This document has been prepared in direct response to the CBC’s Policy requests. It
provides an assessment of the trees within influence of the application area, their
suitability for integration within a completed development, an assessment of the
potential for tree loss/tree works, and to inform opportunities for replacement tree
planting.
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3 DESIGNATIONS RELATING TO ARBORICULTURE
3.1 Tree Preservation Order(s)
3.1.1 The effect of a proposed development on trees is a material consideration therefore
CBC has a duty to ensure that provision is made for protecting important trees when
granting planning permission, this includes the use of Tree Preservation Orders
before a planning application is made (pursuant to Policy BN21). In terms of
development a TPO serves to safeguard high quality trees during design and to
enforce their protection during site clearance and building operations.
3.1.2 On site discussion with the Councils Arboricultural Officer revealed that some of the
site’s trees are scheduled within Tree Preservation Order 1984 (Pers. Comm.
November 2014). A copy of the TPO plan is in provided in appendix C.
3.1.3 Although the order relates to a much wider area, it includes the following trees which
are within influence of the application site:
T1 Category A English Oak (TPO T14)
T2 Category U English Oak (TPO T13)
T19 Category B Common Ash (TPO T18)
T20 Category U English Oak (TPO T19)
T21 category U English Oak (TPO T20)
T22 Category C English Oak (TPO T21)
T23 Category B English Oak (TPO T22)
T24 Category C English Oak (TPO T23)
T27 Category C Silver Birch (remnants of TPO G5)
T28 Category C Purple Plum (remnants of TPO G5)
T29 Category C Weeping Willow (remnants of TPO G5)
T30 Category A English Oak (TPO T12)
T25 Category A English Oak (TPO T11)
T26 Category A English Oak (TPO T10)
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3.2 Conservation Area(s)
3.2.1 Trees within conservation areas that are not subject to a TPO are afforded protection
through a Section 211 of the Town and Country Planning Act 1990. Under a section
211 ‘notice’ the Council requires six weeks prior notice of an intention to fell or work
on a tree within a conservation area. The purpose of the requirement is to provide
either LPA with the opportunity to make a TPO if considered to be appropriate for the
tree(s) in question (pursuant to Policy BN1).
3.2.2 Online enquiries to CBC show that the site does not fall within a conservation area
(Pers. com. November 2014).
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4 BASELINE INFORMATION
4.1 Tree survey
4.1.1 Pursuant to the Council’s policy requirements, the site’s existing trees have been
surveyed under guidance provided by BS5837 (2012). Existing trees within influence
of the application area can subsequently be described by reference to 34no.
individual trees, 4no. groups1 of trees and 1no. hedgerow2. A copy of the survey
methodology is included at Appendix F.
4.1.2 Drawing SBP 001 in appendix A indicates the extent of the tree survey which
corresponds to the application site boundary. As a precaution against harming offsite
trees, the survey area is shown to extend to trees within third party ownership that
may be influenced by future development on the site, e.g. through overhanging
canopies or potential for root development within the site.
4.1.3 The survey provides a record of the species assemblage, dimensions, age,
physiological and structural condition, and the perceived visual importance of each
tree/hedgerow. Full details of each tree, group of trees and hedgerow are provided in
schedule in appendix B and the distribution of the trees is illustrated in appendix D.
4.1.4 The tree survey seeks to provide a baseline on which to balance the demands of the
layout with tree retention and opportunities for enhancing the existing tree stock. To
achieve this position, the tree survey has been undertaken independently of a
detailed proposed layout and prior to any form preparatory works occurring on site.
4.1.5 In all instances, the tree survey has been undertaken visually, from ground level and
from land on which access was permitted. Where access was not available or
practicable, measurements have been estimated; this also typically applies to the
trunk diameters of small trees occurring as understory to larger independently
surveyed tree groups.
1 The term ‘group’ is used to define trees that form a cohesive arboricultural feature, i.e.
aerodynamically, visually or culturally. The assessment of individuals within groups has also
been undertaken where it will be advantageous to make such a differentiation.
2 Hedgerows and substantial internal or boundary hedges are recorded in a similar fashion to
groups with distinctions made for woody plants that comprise distinct trees or significant
variations in the structure/composition. It is not within our scope of work to identify the
importance of hedgerows as it is defined within the Hedgerows Regulations 1997.
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5 TREE CONSTRAINTS
5.1 Design Principles
5.1.1 Proposals for development of the site have been informed by the direct and indirect
constraints provided by the existing tree cover. Over a number of months the
emerging designs have been tested against the tree constraints, incurring revisions to
the design that seek to achieve confident long-term retention of existing trees,
particularly those of importance to amenity.
5.1.2 A summary of the constraints considered during design is provided under the
following subheadings. Details of each of the listed constraints specific to individual
trees, groups and hedgerows is provided within the Tree Schedule found in Appendix
B and illustrated on the Tree Constraints Plan within Appendix D.
5.2 Canopies
5.2.1 The distribution of the Site’s canopy area is illustrated on the Tree Constraints Plan in
appendix D. Canopies have been measured at cardinal points for individual trees and
informed by a topographical survey.
5.2.2 It has been Aspect’s default position that no proposed buildings are sited within the
canopy spreads of retained trees; where it is necessary for proposed structures to be
sited within close proximity to canopies, this has been balanced with an allowance for
future growth and with species attributes.
5.2.3 Vertical canopy clearance has been referenced where it is necessary to permit
access beneath canopies, albeit where justifiable. Our default position has been to
avoid access beneath canopies where possible.
5.2.4 Crown height is provided in order that the design is able to prevent an unreasonable
obstruction to daylight associated with canopy shade. It is however accepted that
some shade may be desirable or acceptable in certain circumstances.
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Root Protection Areas
5.2.5 RPAs are illustrated within Appendix C as a radius from the trunk in plan form and
represent the minimum soil surface area required to enable each tree/group’s
confident retention. It has been our default position that permanent features of the
development are precluded from this area during design unless it can be
demonstrated to be necessary to accommodate an incursion considered to be within
acceptable limits.
5.2.6 It is our opinion that the morphology and disposition of tree roots will, in some
instances, have been influenced by barriers and restrictions to root development, e.g.
adopted highways.
5.2.7 Where the shape of an RPA has been altered, this has been done to include areas
that are considered to be more advantageous to root development. During
manipulation, the area of the RPA has not been reduced.
5.2.8 In accordance with table.2 of BS5837:2012, the relative quality of the trees in respect
to suitability for retention is illustrated by the colour of their Root Protection Area.
5.3 Grading Categories
5.3.1 The quality of the trees is described by reference to BS5837 categories for tree
classification; there are four categories within this model, all of which feature on the
site. A synopsis of the trees is proved below by reference to category.
5.4 Category A tree cover
5.4.1 Representing the principle arboricultural features of the application area, category A
tree cover occurs less frequently than the other classifications. It has been reserved
for 4no. English Oak (T1, T25, T26 & T30) considered be very good examples of their
species and of visual significance to the application area.
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5.5 Category B tree cover
5.5.1 Category B trees are present throughout the application area, occurring as
standalone trees which demonstrate remediable visual defects yet lacking the quality
normally expected of a very good example of the species within the setting.
5.5.2 Category B trees represent moderate arboricultural features of the existing site and
are considered to be important trees that is desirable to retain within a completed
development; they subsequently represent a significant constraint during the
architectural design process and are slightly more abundant than category A tree
cover.
Refer to: T19 Common Ash; T23, T33, T34 English Oak & T31 Common Lime
5.6 Category C tree Cover
5.6.1 With exception of category U trees, all remaining tree cover identified on the site and
its boundaries is considered to represent generally unremarkable examples of its
type i.e.: trees that demonstrate compromised structure, signs of stress; trees of
indifferent structural and physiological appearance and those providing limited or
transient benefits which may be readily replaced. This includes trees that are not
conferred a higher value when present in numbers.
5.6.2 The retention of category C trees is recognised as important where practicable during
design as they help maintain the semi-rural appearance of the site, nonetheless they
are of less priority for retention than category A and B tree cover.
5.7 Category U tree cover
5.7.1 Where tree numbers are enclosed by brackets on the appended plans, this denotes
category U tree cover. Category U trees are of particularly reduced physiological
and or structural condition, such that they are not considered suitable for retention as
living trees in the short term (circa 10 years) or appropriate to retain within the
proposed setting.
Refer to: T2, T20 & T21 English Oak (TPO T13, T19 & T20 respectively); T17, T18
Apple
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5.7.2 Despite representing the least level of constraint during design of the proposals,
category U trees are acknowledged to have existing or potential ecological value
which it might be desirable to preserve3
3 Quantifying this value is outside the scope of this document and is the focus of a separate ecological
study prepared by others as part of the current application.
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6 IMPACT ASSESSMENT
6.1 Preliminary Tree Protection Plan
6.1.1 In keeping with the recommendations of BS5837:2012, our assessment of the
proposed impact upon existing trees is presented in the format of a Tree Protection
Plan incorporating the entire application area (Appendix E).
6.1.2 The purpose of the TPP is to identify: a) trees to be retained and integrated within the
proposed setting, b) illustrate safeguarding measures to ensure that retained trees
are not harmed, either during the course of construction, or as a result of the
development; and lastly, c) identify trees that it is necessary to remove in order to
implement the development and mitigate with new tree planting.
6.1.3 Our assessment and the TPP are informed by the tree survey and constraints plan
balanced with the requirements of the layout and adopted policy. The tolerance of
the trees to disturbance based on species, age, condition and the presence of
surrounding trees and features of the existing site has also been considered.
6.2 Tree Removals
6.2.1 It is our professional opinion that trees should be recommended for removal where, a)
it is necessary and unavoidable to site development within close proximity to existing
trees, such that they cannot be confidently retained as living features, and/or b),
where the amenity value of the tree will be significantly reduced as a result of the
proposals, particularly if already of a low retention priority. In both cases, there is a
presumption that removal will be justified by the provision of replacement trees of
equal or improved suitability for the setting.
6.2.2 Trees recommended for removal are distinguishable from retained trees through the
absence of an RPA or a hatched canopy; identification numbers are shown coloured
red and canopy edges are both dashed and coloured red.
6.2.3 Excluding Category U trees, it is necessary to recommend the removal of 18no.
individual trees, 1no. group of trees and 1no. section of hedgerow to implement the
proposals these are listed within Table 1 (overleaf).
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6.2.4 Category U trees are listed within Table 1 for completeness on account that their
removal is recommended in the interest of sound arboricultural management
associated with their reduced life expectancy in both the existing and the proposed
setting.
6.2.5 There are seven trees recommended for removal that are scheduled within the TPO
(listed below). It has been agreed with the Council’s Arboricultural Officer that despite
their TPO status, these trees are of less importance to the amenity of the site and of
reduced life expectancy when compared to the remaining TPO population.
T2 Category U English Oak (TPO T13):
T19 Category B Common Ash (TPO T18);
T20 Category U English Oak (TPO T19)
T21 category U English Oak (TPO T20)
T27 Category C Silver Birch (remnants of TPO G5)
T28 Category C Purple Plum (remnants of TPO G5)
T29 Category C Weeping Willow (remnants of TPO G5)
6.2.6 It is considered that the remaining category C tree removals (in addition to category U
trees) are of a current size and type that ensures that they can be readily replaced
with tree plantings of improved longevity.
6.2.7 In order to provide construction room for plots 144-159, it is necessary to recommend
the clearance of 2no. short sections of hedgerow H1 subject to being restocked
following construction.
Table.1: Tree removals to implement proposed development (by category)
B C U
T19 Common Ash T3-T13 Common Lime [2] English Oak T14 Silver Birch [17] Apple T15 Bird Cherry [18] Apple T16 Apple [20] English Oak T27 Silver Birch [21] English Oak T28 Purple Plum T29 Weeping Willow G1 Common Ash, Cherry H1 (Partial) Hawthorn, Hazel
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6.3 Access facilitation Pruning
6.3.1 It will be necessary to prune boundary group G2 by c.4m to facilitate the construction
of proposed car parking and built forms close to the southern boundary of the site. In
addition, pruning of H1 by c.1m will be required to provide construction room for plot
48 near to the eastern boundary.
6.3.2 Throughout the entire site, dead branches should be entirely removed from the canopies
of retained trees. Although this work is not required to facilitate construction, it will help
mitigate the risk of future tree related hazards emerging. It would be prudent for this
work to coincide with clearance work on account that access to the trees will be
unimpeded.
6.3.3 All tree works should be undertaken in accordance with BS3998:2010 by a competent
tree contractor to ensure that cuts are performed correctly, and positioned so as to avoid
future structural defects or physiological issues, facilitate growth and maintain aesthetic
value.
6.4 Mitigation Planting
6.4.1 As part of the proposals, a scheme of soft landscape treatment has been prepared to
ensure that the proposed development is set within a robust, high quality landscape
setting and that an appropriate transition between the proposals and the wider
landscape context is created.
6.4.2 The proposed landscape scheme seeks to provide a significant number of trees
across the development site and reinforce the existing vegetation associated with the
site’s boundaries. The numbers of new trees being proposed will more than make up
for the relatively small number of individual tree losses incurred within the detailed
and outline areas of the supplication.
6.4.3 The proposed tree planting will incorporate a range of sizes to ensure a varied, high
quality and successful scheme is achieved. Native species will be focused around
the perimeters of the site and within the natural and semi-natural greenspaces. Within
the built environment the use of ornamental species will create a high quality
landscaped setting which complements the proposed built form.
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6.5 Construction Mitigation
6.5.1 Protective Barriers: Pursuant to the Councils’ advice, it will be necessary to protect
the above and below ground structures of retained offsite boundary tree cover from
damage during construction.
6.5.2 To achieve this, the barrier specification for direct protection should consist of the
default specification provided in BS5837:2012 (shown below). It is considered
essential that barriers are erected prior to occupation of the site for construction
related purposes.
Plate.1 Default Protective Barrier Specification
6.5.3 The siting of tree protection barriers is illustrated within appendix D, which in all
instances is considered to be practicable without conflicting with construction if
located either on the edge of the RPA or the canopy extents (whichever is the
greater). Where proposed access is required with RPA’s (see below), any activity will
be undertaken in the presence of a supervising arboriculturist and barrier positions
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can be repositioned appropriately as part of this brief. The position for the relocated
barriers is illustrated within Appendix E with a yellow dotted line.
6.5.4 It would be prudent for the project arboriculturalist to oversee the initial erection of
tree protection barriers and provide written confirmation to CBC’s arboricultural officer
once barrier erection is complete.
6.5.5 Proposed Hard Surfaces: The introduction of a pedestrian footpath is proposed
within the RPA of T22 English Oak (c.11% of the RPA). This area is currently under
hard surface.
6.5.6 A precautionary approach to managing the incursion will be to incorporate the design
recommendations listed in 7.4.2 of BS5837:2012, i.e. the preclusion of excavation
into soil, avoidance of localised compaction, and maintained permeability. This can be
achieved if the path is founded on 75mm Standard Cell CellWeb® overlain by a
permeable tarmac wearing course (i.e. TarmacDry®) with non-invasive retaining
edges. Arboricultural supervision during these works is strongly recommended.
6.5.7 The extent of the incursion (detailed above) is considered reasonable, particularly
where exchanged for the existing hard surface. To ensure confidence in the trees
tolerances towards proposed no-dig incursions and to overcome any existing
compaction within RPAs, it is strongly recommended that the full RPA (where on site)
were to be Terravented incorporating a Mychorizial Fungi and Bio stimulant injection.
This work should be undertaken prior to the laying of the cellweb sub-base.
6.5.8 Supervised excavations: The introduction of a road and car parking provision is
proposed within the RPA of T1 English Oak (c.10% of the RPA), T22 English Oak
(c.4% of the RPA), T25 English Oak (.c 3% of the RPA) and T30 English Oak (c.7%
of the RPA). In addition a proposed building is proposed within the RPA of T33
English Oak (<1% of the RPA) and T34 English Oak (c.2% of the RPA).
6.5.9 As a precaution against avoidable disturbance to the RPAs, including damage to tree
root structures it is recommended that the installation of all the features listed above
adopt advice provided in section 7.2 of BS5837:2012 under the heading ‘Avoiding
Physical Damage to Tree Roots during Demolition or Construction’.
6.5.10 In the case of hard surfaces, an arboricultural watching brief and the adoption of the
procedures for manual excavation should be combined with the siting of barriers
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500mm back from the proposed kerb routes to enable sufficient working room. Where
proposed built forms are to be constructed within RPAs, the working room should be
increased to c.2m.
6.5.11 Ground Boarding: Where barriers are to be offset from proposed built forms, the
intermediate area of exposed RPA will need to be protected during construction by
ground boarding as a precaution against localised ground compaction. It is
recommended that ground protection used is to consist of polyethylene trackmats, the
locations of which are illustrated in Appendix E with a light blue hatch.
6.5.12 Phasing and Services: At this stage, Aspect has not been able to assess the
influence of all proposed services, levels, or provided input regarding the phasing of
construction works as part of the application put forward. Pending the acceptability of
the scale and nature of the proposed development to Crawley District Council it is
anticipated that these details will be the subject of a condition i.e. the focus of an
Arboricultural Method Statement and detailed Tree Protection Plan.
6.6 Future Pressure
6.6.1 Tolerance to trees is a subjective matter and seasonably variable, therefore it is
reasonable to presume that potential occupiers will factor the presence of retained
trees and hedgerows as a major feature of the development when deciding whether
to commit to living within close proximity to them. To alleviate any potential concerns,
it is considered that the TPO is an appropriate control measure to prevent
unsympathetic pruning.
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7 CONCLUSIONS
7.1 In accordance with the adopted policies of Crawley District Council in the context of
proposed development, a BS5837:2012 survey and assessment has been prepared to
inform the retention of important trees and their contribution to amenity.
7.2 The application demonstrates consideration for all trees within influence of the proposed
design and accommodates the majority of trees considered important to the amenity of
the existing (and proposed) site. In addition, the long-term integration of significant trees
and groups is considered practicable subject to temporary protection during construction
and mitigation for permanent development within RPAs. As part of the design process the
retention of all the significant trees subject to the TPO has also been facilitated.
7.3 Regardless of poor quality trees that should be removed irrespective of development, the
proposals incur the necessary removal of 18no. trees and 1no. group. The impact of these
removals is considered to be acceptable through confident, long-term, integration of
appropriate tree cover, alongside opportunities to provide diverse mitigation.
7.4 Replacement tree planting is expected to increase the canopy area of the site, whilst
enhancing the long-term amenity potential of the site’s overall tree stock.
7.5 In the absence of long-term harm to important trees scheduled within a TPO in particular,
it is our professional opinion that the proposals put forward by BDW Southern Counties
Ltd. allow for technical confidence in the long-term viability of retained and appropriate
tree cover. The proposals are therefore considered supportable from the arboricultural
perspective and in terms of Local Plan Policy and Saved Policywhere it relates to trees.
This opinion is subject to the provision of replacement tree cover, and the adoption of
future safeguards as identified within this document.
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8 RECOMMENDATIONS (future work)
8.1 A detailed Arboricultural Method Statement could be required by Condition and
subsequently prepared which expands on appendix E.
8.2 Heads of Terms for the Method Statement are advised to include: specifications for tree
protection barriers, including revisions to barrier locations; a schedule of tree works; a
procedure for above soil installations, hard surface removal and excavations within RPAs;
phasing of work; and a scheme for auditing tree protection and subsequent reporting to
the LPA should feature explicitly throughout.
8.3 Detailed Tree Protection Drawings should be prepared to 1:200 scale to support the AMS,
with detail given of proposed levels and service routes.
PREPARED BY:
Dr Richard Curtis Bsc (Hons) PgDip PhD MArborA
Senior Arboricultural Consultant
T: 01295 276066
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDICES
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDIX A
SURVEY BOUNDARY PLAN (8842 SBP 01)
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDIX B
TREE SURVEY SCHEDULE (8842 TS 01)
8842 TS 01
BS 5837:2012 Tree Schedule: Ifield Community College, Crawley
BS5837:2012 Tree Survey: Explanation of Survey Criteria
The following survey should not be interpreted as a report on tree health and safety. Aspect’s opinion of tree condition and structural potential is valid for a limited period of 12 months from the date of inspection. Validity is assumed in the absence of inclement weather and no change to the trees existing setting.
Project: 8842 Ifield College, Crawley Survey Date: 07 July 2014
Surveyor: James Bardey & Jamie Pratt
Tree Number
Common Species Name
Trunk Diameter
(mm)
Height (m)
Crown Spread (m) Crown Clearance
(m) Life Stage Physiological
Condition Structural Condition Comments BS5837
Category
RPA Radius
(m) N E S W radial
Area around tree deemed to contain sufficient roots and rooting
volume to maintain the tree’s viability, and where the protection of
roots and soil structure is a priority.
Sequential reference number cited
on all aspect drawing.
Height of first significant branch and/or
canopy
e.g.: young, semi-mature, early-mature,
mature or over-mature
e.g.: above-average, average,
below average or dead
e.g.: good, indifferent, poor, or hazardous
Height and Crown spread measured to the nearest half
meter; # denotes where this is estimated.
Measured to the nearest 10mm; # denotes
estimated diameter where access is not
possible.
Category prefix A-C denotes arboricultural quality, decreasing
from A (high) to C (low); Subcategories 1, 2 and 3 highlight
associated arboricultural (1), landscape (2) and ecological (3)
qualities.
Category U trees are those in such a condition that they
cannot be retained as living trees in the current context for
General observations, i.e. defects, preliminary
management recommendation, presence of
pests/disease, perceived significance.
BS5837:2012 Tree Schedule Ifield Community College, Crawley
N E S W radial
1 English Oak 1100 21 14 (NE) 11.5 10 11.5 4.5 Mature Average Good
Stout stemVery large buttress root to South Maintains single leader for majority of height Even primary branch distribution Previously crown lifted and thinned Structure typical for speciesConsidered to be of high arboricultural quality and value
A12 13.2
2 English Oak 900# 15 8.5 5 Mature Dead Poor Standing deadwood U N/A
3 Common Lime 250 6 3 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPA C12 3.0
4 Common Lime 260 6 3 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPA C12 3.0
5 Common Lime 270 6 3 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPA C12 3.3
6 Common Lime 270 6.5 3 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPA C12 3.3
7 Common Lime 270 6.5 3 0.5 Early Mature Average Indifferent
Structure typical for species Hard surface within RPACohesive canopies Fork bark inclusion
C12 3.3
8 Common Lime 260 6.5 3 0.5 Early Mature Average Indifferent
Structure typical for species Hard surface within RPACohesive canopiesFork bark inclusion
C12 3.0
9 Common Lime 260 6.5 3 0.5 Early Mature Average Indifferent
Structure typical for species Hard surface within RPACohesive canopies Spoil to East Fork bark inclusion
C12 3.0
10 Common Lime 350 8 4.5 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPALarge structural surface roots visable
C12 4.2
11 Common Lime 290 9.5 3.5 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPACohesive canopies
C12 3.6
12 Common Lime 310 9.5 3.5 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPACohesive canopies
C12 3.6
13 Common Lime 240 9.5 3.5 0.5 Early Mature Average Indifferent Structure typical for species Hard surface within RPACohesive canopies
C12 3.0
14 Silver Birch 170 6.5 2 1.75 Early Mature Average Indifferent C12 2.115 Bird Cherry 410 6 4.5 2 Mature Below Average Poor C12 4.8
16 Apple 17090 3 3 1.75 Early Mature Average Poor C12 2.1
17 Apple 130170 3 3
1.75
Early Mature Average Poor
Stout stem forking at approx 500mmPrimary limbs crossing Union decayedConsidered to be of reduced future potential
U N/A
18 Apple 200160 4 3.8 1.5 Early Mature Average Poor
Oringinally 3 codominant stems only 2 remainForking at approx 500mmDecay in unionConsidered to be of reduced future potential
U N/A
19 Common Ash 420440 13 7.25 7 6.5 7 2.5 Mature Average Indifferent
Folking at approx 1m Co-dominant stemMinor impact wound to North at 1.25m Upper canopy structure is typical for species Considered moderate arboricultural quality and value
B12 7.2
RPA Radius
(m)
Crown
Clearance (m)Life Stage
Physiological
Condition
Structural
ConditionComments
Tree
Number
Common Species
NameHeight (m)
Trunk
Diameter
(mm)
Crown Spread (m)BS5837
Category
Tree Survey Schedule: 7 July 2014
BS5837:2012 Tree Schedule Ifield Community College, Crawley
N E S W radial
RPA Radius
(m)
Crown
Clearance (m)Life Stage
Physiological
Condition
Structural
ConditionComments
Tree
Number
Common Species
NameHeight (m)
Trunk
Diameter
(mm)
Crown Spread (m)BS5837
Category
20 English Oak 980 13 5.5 9 8 7 3.25 Mature Below Average Poor
Possible hollow buttress roots Significant basal decayCrown tip die-back Considered to be of reduced future potential
U N/A
21 English Oak 830 18 6.5 5.5 7.2 7.5 4 Mature Below Average Poor
Maintains single leaderCollybia fusipes (Spindle shank) fungal brackets located at mulitple positions at base of stem and structural root flares - root decaying Crown tips dieback likely caused by root decay fungal infectionAbove average epicormic growth throughout stem and crown Terminal decline Considered to be of reduced future potential
U N/A
22 English Oak 930 15 7.75 8.5 13 7 2 Mature Average Indifferent C12 11.1
23 English Oak 1000# 15.5 9.25 9.11 9# 9.5 3.25 Mature Average Moderate
Off-site Single stemMaintains single leaderStructure typical for species Hazard beam failure to North at 4.5m
B12 12.0
24 English Oak 650# 14# 8 8 4.5# 4.5# 3 Mature Average Indifferent C12 7.8
25 English Oak 1110 19 12.8 6.25 9 9 4.5 Mature Average Good
Complete structural limb tear out wound at 10mTypical branch distributionDeadwood to East Considered to be of high arboricultural quality and value
A12 13.2
26 English Oak 1000# 21 9 11 6.5 6.5 3.5 Mature Average Good
Off-site Single stem Obscurred by Ivy Forking at 4mUnable to inspect - restricted access Possible heavy weight loading on lower limbs to South and West
A12 12.0
27 Silver Birch 320 11.5 4 2.5 Early Mature Average Indifferent C12 3.928 Purple Plum 470 6.5 4 2 Mature Average Indifferent C12 5.729 Weeping Willow 620 7.5 7.75 5 6 6.8 3.5 Mature Average Indifferent C12 7.5
30 English Oak 1230 21 8 9.5 12 9.5 4 Mature Average Good
Signifcant buttress rootsPreviously thinnedSlightly above average deadwood Considered to be of high arboricultural quality and value
A12 14.7
31 Common Lime480360410
12 6.75 7.75 7 5.5 3 Mature Average Poor
Above average epicormic growth Structure typical for species Considered moderate aboricultural quality and value Filters views external to site
B2 8.7
32 Silver Birch 330 12 3.75 3 Early Mature Average Indifferent C12 3.9
33 English Oak 600# 13 5.5 4 Mature Average Indifferent
Off-site Obscurred by Ivy Structure typical for species Dimesions estimated - restricted access Considered to be of moderate arboricultural quality and value
B2 7.2
34 English Oak 800# 15 6 4 Mature Average Indifferent
Off-site Obscurred by Ivy Previously reduced Structure typical for species Dimesions estimated - restricted access Considered to be of moderate arboricultural quality and value
B2 9.6
Tree Survey Schedule: 7 July 2014
BS5837:2012 Tree Schedule Ifield Community College, Crawley
N E S W radial
RPA Radius
(m)
Crown
Clearance (m)Life Stage
Physiological
Condition
Structural
ConditionComments
Tree
Number
Common Species
NameHeight (m)
Trunk
Diameter
(mm)
Crown Spread (m)BS5837
Category
G1 Common AshCherry 110 max 5 2.5 1.75 Young Average Poor Upper crown structure typical for species
Multi-stemmed from base C12 1.2
G2
Silver Birch Sycamore PlumEnglish OakElder
300 max 11 max 6 max 2.5 Young - Early Mature Average Indifferent
Off-site beltStructure typical for species Provides screening
C12 3.6
G3 Lawson cypress 100# 4 1 0.5 Young - Early Mature Average Indifferent
Off-siteUnmaintained garden hedge Intermittent
C12 1.2
G4 Ash hedge Horse chesnut 500 7--9 3.5-6 0.75-1.75 Young - Early
Mature Average Indifferent Off-site Hedge formaly maintained now neglected Structure typical for species
C12 6
H1 Common HawthornHazel 100 max 2.5 1 0.5 Young Average Indifferent Structure typical for species
Maintained hedgerow C12 1.2
Tree Survey Schedule: 7 July 2014
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDIX C
TREE PRESERVATION ORDER (Plan No. P1501/96)
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDIX D
TREE CONSTRAINTS PLAN (8842 TCP 01)
1(TPO:T14)
[2] (TPO:T13)
3
4
5
6
7
8 9
10
11
12
13
14
15
16
[17][18]
19 (TPO:T18)[20] (TPO:T19)
[21] (TPO:T20)
23 (TPO:T22)
2728
29
30 (TPO:T12)
31
32
22 (TPO:T21)
24 (TPO:T23)
G1
G2
G3
H1
H1
25 (TPO:T11)
26 (TPO:T10)
33
34
G4
G3
Horse Chestnut
T30: Approximately. 11% of RPA underrecent development including excavatedarea south of building footprint. Proposalsto provide an area equivalent to theincursion contiguous to the remaining RPA.
T27-T29 (TPO:G5 remnants)
Tree Constraints Plan
MAY 2015
8842 TCP 01 Rev B
DATE
DRAWING NUMBER REVISION
CLIENT
TITLE
Based on topographical dwg no. Topographical Survey 20140707.dwg
REVISIONS
SCALE
1:1000 @ A3 GWDRAWN
KEY:
Tree Numbers
Category 'A' RPA
Ifield College Crawley
Barratt Homes
Tree Canopies
Chk'dDrawnNOTEDATEREV
15
[8]
Category 'B' RPA
Category 'C' RPA
Category 'U' Trees
0m 40m10m 20m1:1000 @ A3
Shading Arc
Cited from Google Earth
Note: T32,T33,T34,G1,G2,G3 and H1 are not onthe topographical survey and their locations areapproximated using scale aerial photographs andby taking measurements onsite.
Regenerative scrub present on entire site. Speciesinclude Goat Willow, Silver Birch, Buddlieja, Elm,Elder, English Oak, Sycamore and Ash. Below thethreshold for the British Standard. Height 6mmaximum. Average DBH = 50mm.
RCGWTPO reference added03.11.14A
B
RCGWUpdate to hatching27.05.15B
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDIX E
TREE PROTECTION PLAN (8842 TPP 01)
[17][18]
[20] (TPO:T19)
[21] (TPO:T20)
[2] (TPO:T13)
1(TPO:T14)
19 (TPO:T18)
23 (TPO:T22)
30 (TPO:T12)
22 (TPO:T21)
24 (TPO:T23)
25 (TPO:T11)
26 (TPO:T10)
T27-T29 (TPO:G5 remnants)
3
4
5
6
7
8 9
10
11
12
13
14
15
16
2728
29
31
32
G1
G2
G3
H1
H1
33
34
G4
G3
Horse Chestnut
G2 target pruned back 4m toallow sufficient clearance forproposed parking spaces andconstruction room.
T1: Areas of proposed hard surface within RPA tobe manually excavated under direct arboriculturalsupervision. Tree protection barriers to be relocatedto secondary position post construction.
G4
T22: Areas of proposed hard surfacewithin RPA to be constructed above soil.Tree protection barriers to be relocatedto secondary position post construction.
T30: Proposed area of road within RPA to bemanually excavated under direct arboriculturalsupervision. Tree protection barriers to berelocated to secondary position post construction.
Proposed parking spaces to utiliseexisting hard surface footprint.
H1: Clearance required to provideconstruction room. Restockedfollowing construction. Extent ofremoval to be determined onsite byproject arboriculturalist.
T25: Areas of proposed hard surfaceand building footprint within RPA tobe manually excavated under directarboricultural supervision.
T23: Ground boarding to be positionedbetween proposed building footprint andtree protection barriers.
T31: Ground boarding to bepositioned between proposed buildingfootprint and tree protection barriers.
H1: Removal of c.5m to accommodateproposed pedestrian access.
T33 & T34: Area of proposed building footprint withinRPA to be manually excavated under directarboricultural supervision. Tree protection barriers tobe relocated to secondary position during construction.
T33 & T34: Ground boarding to bepositioned between proposed buildingfootprint and secondary barrier position.
T22: Areas of proposed road and parkingwithin RPA to be manually excavatedunder direct arboricultural supervision.
T25: Ground boarding to bepositioned between proposed buildingfootprint and tree protection barriers.
H1 target pruned back toallow sufficient clearance forproposed parking spaces andconstruction room.
H1 target pruned back toallow sufficient clearance forconstruction room.
Tree Protection Plan
MAY 2015
8842 TPP 01
DATE
DRAWING NUMBER REVISION
CLIENT
TITLE
Based on layout ref: 081006-BAR-SC-01-PRELIM-14.05.15.dwg
REVISIONS
SCALE
1:1000 @ A3 GWDRAWN
KEY:
Tree Numbers
Category 'A' RPA
Ifield College Crawley
Barratt Homes
Tree Canopies
Chk'dDrawnNOTEDATEREV
Tree Protection Barrier
15
[8]
Category 'B' RPA
Category 'C' RPA
Category 'U' Trees
0m 40m10m 20m1:1000 @ A3
Key1 Standard scaffold poles2 Heavy gauge 2m tall galvanized tube and welded mesh infill panels3 Panels secured to uprights and cross-members with wire ties4 Ground level5 Uprights driven into the ground until secure (minimum depth 0.6m)6 Standard scaffold clamps
Default Barrier Specification, cited BS 5837:2012
Tree Protection Barrier(2nd Position)
Cited from Google Earth
Note: T32,T33,T34,G1,G2,G3 and H1 are not onthe topographical survey and their locations areapproximated using scale aerial photographs andby taking measurements onsite.
Trees to be Removed
Manual Excavation
Above Soil Surfacing
7
Ground Boarding
Ifield Community College, Crawley June 2015
Arboricultural Impact Assessment 8842_AIA.001
APPENDIX F
TREE SURVEY METHODOLOGY
Ifield Community College, Crawley May 2015
Tree Survey Methodology 8842_TSM.001
May 2015
Tree Survey Methodology
The tree survey is a form of Visual Tree Assessment undertaken by a competent and qualified
arboriculturist on 9th December 2014 during cold and clear conditions. Tree locations are
identified via a topographical survey; locations of any trees excluded from the topographical
survey were plotted on site. The purpose of the survey is to record information about trees on
or adjacent to the site to inform design options. In keeping with clause 4.4 of BS5837: 2012
‘Trees in Relation to Design, Construction and Demolition’, the survey provides a record of the
following parameters:
Tree Numbers: all individual trees are sequentially numbered. Groups of trees, woodlands and
hedgerow are also sequentially numbered with a corresponding prefix relevant to their type
e.g. G, W or H respectively; the identification of trees as woodland, groups of trees or within
hedgerows is undertaken where appropriate. The identification of trees as individuals within
collections has been made where it is considered sensible to make such a differentiation.
Species: listed by common name
Stem Diameter: given in millimetres and obtained by measuring single/multiple stems at
1.5m using a diameter tape in accordance with Annex C within BS5837:2012. Diameters of
inaccessible trunks are estimated and provided with the suffix ‘#’.
Tree Heights: determined using a clinometer and measured to the nearest 500mm. Heights
are estimated where specific triangulation is not achievable and by reference to measured
trees nearby (provided with the suffix ‘#’).
Crown Spreads: measured at cardinal points using a Leica DistoTM laser distance measurer.
Measurements were recorded to the nearest 250mm. Inaccessible crown spreads are
estimated based on measured canopies nearby and provided with the suffix ‘#’
Crown Clearance: The height of the first significant living branch and/or canopy (as
appropriate) is recorded using a Leica DistoTM laser distance measurer to inform vertical
ground clearance. Crown clearance may be higher or lower than the first significant branch.
Estimated clearances are provided with the suffix ‘#’. Height of first significant branch will be
provided where considered advantageous to make the distinction.
Ifield Community College, Crawley May 2015
Tree Survey Methodology 8842_TSM.001
May 2015
Life Stage – The age of trees, groups of trees, hedges and woodlands are defined as follows:
Young (within the first 1/4th of life expectancy)
Semi-mature (within the second 1/4th of life expectancy)
Early Mature (within the third 1/4th of life expectancy)
Mature (within the fourth 1/4th of life expectancy)
Over Mature and Veteran (exceeding normal life expectancy)
Veteran (significantly exceeding normal life expectancy)
Physiological and structural condition: physiological condition defined as follows; good, above
average, average, below average, poor or dead. Structural condition is defined as: good,
moderate, indifferent, poor or hazardous
Comments: further observations were recorded where necessary i.e. details regarding defects,
preliminary management recommendations, presence of pest/disease and perceived
significance.
BS5837 Category: pursuant to BS5837:2012 section 4.5 and cascade chart for tree quality
assessment (refer to reproduced Table 1 overleaf). Trees qualifying under a given category (A-
C and U) and any appropriate subheading (1-3) are considered to fall within the scope of that
category’s definition.
Estimated Remaining Contribution. Described` as a guideline only and in terms of years: <10,
10+, 20+ and 40+ relevant to category U, C, B and A respectively. This information is not
provided on the tree schedule to avoid conclusions based upon ‘life expectancy’.
Ifield Community College, Crawley May 2015
Arboricultural Impact Assessment 8842_ AIA.001
May 2015