View - Staffordshire County Council

Rob Keyzor
Tree Surgeons &
Arboricultural Consultants
Telephone & Fax: 0 1 7 8 5 2 8 4 0 8 8 w w w . r o b k e y z o r . c o . u k
PRE DEVELOPMENT TREE INSPECTION
AND REPORT
at
STANDON BOWERS OUTDOOR EDUCATION
CENTRE .
for
STAFFORDSHIRE COUNT Y COUNCIL
BY
Nik Pearson RFS Cert Arb & Rob Keyzor. Fd.BSc.Arb
November 2012
CONTENTS
SUMMARY .........................................................................................................................................3
1.
INTRODUCTION ..........................................................................................................................4
2.
TERMS OF REFERENCE..............................................................................................................4
REFERENCE
3.
THE SITE.....................................................................................................................................5
SITE
4.
OBJECTIVES ...............................................................................................................................5
6.
KEY TO THE CONDITION SURVEY ................................................................................................8
7.
FINDINGS ................................................................................................................................. 10
8.
MANAGEMENT RECOMMENDATIONS ...................................................................................... 12
Key to management recommendations table ....................................................................................12
9.
TREE PROTECTION PROVISION ................................................................................................. 14
10.
IMPACT OF TREES ON THE DEVELOPMENT ........................................................................... 16
11.
IMPACT OF DEVELOPMENT ON THE TREES ........................................................................... 16
12.
CONCLUSION ........................................................................................................................ 17
APPENDIX I ...................................................................................................................................... 18
TREE CONSTRAINTS PLAN (extract of an AutoCAD file sent separately as there is too much
information for 1 A4 page.) ................................................................................................................18
APPENDIX II ..................................................................................................................................... 20
Photo 1
looking south west. (T1 Oak in the centre of the picture and site to the left). ..................20
STANDON BOWERS, SCC -NOVEMBER 2012 Page 2 of 20
SUMMARY
This survey and report is required to support a planning
application to install a single storey classroom in place of and on
the same footprint as a storage shed.
All data collected and subsequent calculations are in accordance
with BS 5837: 2012.
There appears to be no major arboricultural constraints to prevent
this .development although minor works are recommended.
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1.
INTRODUCTION
1.1 This document is the written opinion of its authors in the context of the
recommendations of BS5837: 2012 Trees in Relation to Construction.
1.2 It is intended for use as a guide for the site designers/ planners and
managers.
2.
TERMS OF REFERENCE
2.1 We have received instructions from Mr Richard Lawrie, Senior Property
Surveyor at Staffordshire County Council to prepare a tree report in
accordance with BS 5837: 2012 Trees in Relation to Construction –
Recommendations for trees in proximity to the storage shed close to the
northern boundary of the Standon Bowers grounds.
2.2 We are in receipt of the following documents:
2.2.1 Grounds Tree Survey drawing No.01– Site Layout as a Pdf
2.2.2 Standon Bowers AutoCAD file.
2.3 The survey is to collect data to prepare a tree retention and removal plan,
tree protection plan and remedial works schedule in accordance with
BS5837: 2012.
2.4 A survey of trees was carried out on the 20th November 2012 by Rob Keyzor
of Rob Keyzor Tree Surgeons.
2.5 We understand that it is proposed to remove the existing storage shed and
install a single storey classroom on the same footprint as the existing shed.
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3.
THE SITE
3.1 The site is part of the Standon Bowers outdoor education centre. It is
currently used as a storage shed marked ‘A’ on the attached PDF titled
‘Grounds Tree Survey’. It is accessed on foot from the main visitor entrance
and tarmac open space to the north of the existing classroom marked ‘B’ on
the attached PDF.
3.2 To the south the shed is bounded by grass open space, to the east by a large
tarmac play area and coach park, to the north and west by stone surfaced
storage area.
3.3 As the proposal is to install the new classroom on the footprint of the
existing storage shed the development proposal will also involve demolition
of the Tin sheet clad storage shed.
3.4 To the north west of the site is the neighbouring farm house and gardens to
which we did not have access.
3.5 The existing shed apparently has an overground electrical supply from the
adjacent classroom.
3.6 Demolition and construction access will be via the coach entrance and
parking area to the east of the building.
4.
OBJECTIVES
4.1 We are to survey the tree(s) likely to influence or be influenced by the
proposals and collect data to comply with BS 5837: 2012. (There are other
trees in proximity to the proposed site in the adjacent farm that are not
likely to influence the development and therefore do not form part of this
report.)
4.2 Produce a constraints plan (showing trees to be removed) and a provisional
tree protection plan, and highlight any impact the trees might have on the
development or that the development might have on them.
4.3 To present information in documents suitable to accompany planning
applications to the local authority.
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5.
LIMITATIONS
5.1 The information within this report is intended to be in accordance with BS
5837: 2012 Trees in Relation to Construction and is not to be used to
discharge tree owner’s liabilities for trees in poor or hazardous condition.
5.2 The tree constraints plan is based on some measurements taken at the time
of the survey; where any issues arise exact tree positions may need to be
plotted and additional plans submitted.
5.3 This document should be regarded as a management and design tool, to
enable each tree to be given due consideration as part of the design and
planning process, and should only be used in this manner.
5.4 This inspection was from ground level only.
5.5 The findings and recommendations of this report are limited to site
conditions on the date of the inspection.
5.6 All recommendations for management should be completed within a one
year period unless specified otherwise (subject to Local Authority approval).
5.7 Trees are dynamic natural structures and where retained require frequent
monitoring if the potential for failures are to be identified.
5.8 Local and national weather conditions have been subject to ‘unseasonal’
fluctuations in recent years that can and have affected trees’ natural
seasonal and annual progression, from spring leaves to autumn leaf fall.
Trees are self-optimising organisms and on the whole will adapt to these
changes to their benefit. This may lead to unforeseen circumstances such as
unprecedented rooting depths or loss of limbs (summer branch drop). These
events and their consequences cannot be reliably predicted or planned for
and are therefore excluded from this report.
5.9 Information pertaining to tree structure, tree defects, fungal strategies and
tree/ pathogen interactions is increasingly up dated and researched further,
however, the complexities of tree classifications, localised environmental
variations, and the succession of wood decaying pathogens make precise
quantification of tree failure-potential unachievable.
5.10
Trees with no external evidence or only seasonal indicators of defects
may still fail. Unexpected ‘freak’ weather conditions, or wind forces from
abnormal directions can cause catastrophic failure of a tree or its parts.
These conditions cannot be predicted and are therefore excluded from this
report; however it is strongly recommended that you contact us following
such conditions.
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5.11
Prepared 20th November 2012
5.12
Signed…………………Rob Keyzor.…………………R.Keyzor.
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6.
KEY TO THE CONDITION SURVEY
The findings are presented as they were recorded under a number of different
headings. This means the trees are recorded systematically and consistently.
What follows is a description of each heading: • Ref – this relates to the number given on the plan and is for identification
purposes only; it has no quantitative or qualitative significance.
• Species – this is presented using common English names and binomial botanic
names, where possible. Trees are not identified to the cultivar level.
• Measurements – data pertinent to BS5837: 2012
• Tree Height - a sight estimate only. Given in metres,
• Stem Diameter – the measured at 1.50m for all stems (noted by multiple
entries).
• Crown Spread – distance from stem to crown extremities at four Cardinal
points. Given in metres.
• Crown Clearance – estimated and given in metres. This is an estimate of
the distance between ground level and the lowest point of the tree
canopy (usually foliage but can estimated to woody material if more
appropriate). 0.0m denotes a tree that is feathered to ground level,
i.e. where the branches start at the base and may touch the ground
level.
• For the crown height the lowest branch and its orientation are noted,
particularly where it may cause a constraint to layout proposals.
• Age Class – trees are put into the following classes indicating various ‘stages’ in
their lives, reflecting the progression from seedling to senescence and death or
collapse: • Young – newly planted, seeded or recently established.
• Early mature – current annual increment stabilises, although it has not
reached full potential stature.
• Mature – full potential stature reached. Young mature and mature stages
may account for about half of a species’ life span.
• Over mature – Crown begins to collapse. The annual increment is slower
than the pace of many major decay organisms.
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• Condition – Overall condition of the tree within the broad categories below; • Good – no (significant) problems or immediate need for remedial works.
• Fair – notable hazards (may need reviewing at prescribed intervals)
• Poor – significant defects pertaining to tree or target area health and
safety
• Very Poor/Dead – moribund or entirely dead trees.
• Observations – Notes about the tree or its environment that are pertinent to
tree management.
• Rem.Contrib. = Remaining Contribution – an estimation of a trees likely
remaining safe life expectancy in decade increments. It is intended as
indication of amenity value as a deciding factor for a tree’s worthiness as a
constraint to proposed development.
• Retention Category – The categories recommended in BS 5837: 2012 can be
summarised as follows: Category U – Trees that have no or extremely short- term value, dead, dying
or diseased trees or trees that have less than 10 years remaining
contribution.
Category A - (1 – 3) Trees with high quality and value and an estimated
remaining life expectancy of 40 years that could be retained for arboricultural
(1) and/or landscape (2) and/or cultural reasons (3).
Category B - (1 – 3) Trees with moderate quality and value and an estimated
life expectancy of 20 years that could be retained for arboricultural (1) and/or
landscape (2) and/or cultural reasons (3).
Category C – (1-3) Trees with low quality and value and a remaining
estimated life expectancy of only 10years or less and could be retained for
arboricultural (1) and/or landscape (2) and/or cultural reasons (3).
The categories are recorded on the plan as a colour: DARK RED - Category U
LIGHT GREEN – Category A (1-3)
MID BLUE - Category B (1-3)
GREY - Category C (1-3)
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7.
FINDINGS
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Reference
Species
Botanical
Height
(m)
Stem
Diam
(mm)
Spread
North
(m)
Spread
South
(m)
Spread
East (m)
Spread
West (m)
Crown
Clearance
(m)
Lowest
Branch
Height (m)
Lowest
Branch
Direction
Age Class
Condition
Observations
001
Oak
Quercus sp.
10
810
7.00
est.
7.20
2.80
6.10
2.00
4.00
S
mature
Good
002
Mixed
Beech,
Laurel and
Hawthorn
remnant
hedge
Prolific epicormic on the lower
trunk, branches interfering with
adjacent building.
Remnant hedging with large
gaps, poorly maintained. Offer
only reduced screening to
neighbouring property.
1.80
2.00
1.00
poor
Rem.
Contrib.
(yrs)
Retention
Category
20
B 2/3
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C1
8.
MANAGEMENT RECOMMENDATIONS
Key to management recommendations table
•
Ref – this relates to the number given on the plan and is for identification purposes only;
it has no quantitative or qualitative significance.
•
Species – this is presented using common English names . Trees are not identified to the
cultivar level.
•
Management recommendations – these reflect the on site observations of the
inspector and are considered in context of the proposed development where
appropriate. All recommendations are intended to prolong the long term health
and safety of the tree, abate a nuisance or reduce a risk. All are good
arboricultural practice and are in accordance with BS 3998: 2010. They are divided
into pre, during and post construction as a means of ensuring adequate protection
and management throughout the development.
•
Root protection area distances – Distance measured from the nearest point on the
trunk. This is used to demonstrate likely tree constraints and provide accurate
information of available build space.
STANDON BOWERS, SCC -NOVEMBER 2012 Page 12 of 20
‘Pre’ Construction
management recommendations
‘During’ Construction management
recommendations
‘Post’ Construction
management recommendations
Root protection Area
Measurements.
Oak
Crown lift to give 2 metres
clearance from shed.
Protect trees with
protective barriers - as
shown on plans in
Appendix I.
No action required.
1.50m from trunk
Hedge of Beech,
Laurel,
Hawthorn
No action required
Protect trees with
protective barriers - as
shown on plans in
Appendix I..
Plant up gaps and
maintain hedge
1.50m from stem:
Reference
Species
001
002
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9.
TREE PROTECTION PROVISION
9.1
As a means of protection for tree roots BS 5837:2012 ‘Trees in relation to
Construction’, recommends that a Root Protection Area (RPA) be calculated for
category A or B trees (and C category if they are retained in the final layout). This is a
minimum area in m2, based on the radius of the stem, which is to be left undisturbed.
9.2
The arboricultural significance of the RPA is that stripping of soil levels, demolition of
existing buildings, hard surfaces and foundations or new building in very close
proximity to trees or hedges can cause irreversible damage, render them dangerous
or even kill them. In the main this is a result of damage to roots of all diameters.
9.3
Building would not only include the final elevations of any built structure but the
space around it used to install services, access for ground-works and scaffold and
other site related logistics.
9.4
The RPA is a total exclusion zone which means there should be no vehicular or
pedestrian traffic, demolition, site stripping or storage of materials etc within the
prescribed area.
9.5
The RPA is established on site through the use of robust barriers that should be
capable of withstanding accidental impacts from plant movements. BS5837: 2012 has
specific requirements of such a barrier, see Figure 2, over the page. To this barrier all
weather notices should be attached with the words;
“CONSTRUCTION EXCLUSION ZONE –NO ACCESS”
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9.6
Demolition of existing built structures and hard landscaping should be limited to that
which is above ground only and on the footprint off the original structure.
9.6.1
9.7
There should be no motor mechanical excavations within the RPA without local
authority approval and arboricultural supervision.
Additional tree protection could be afforded by careful planning and execution of
construction works and good housekeeping and site management.
STANDON BOWERS, SCC -NOVEMBER 2012 Page 15 of 20
10. IMPACT OF TREES ON THE
DEVELOPMENT
10.1 Due to the aspect and orientation of the site direct shading of sunlight is not an issue
although there will be some denudation in indirect light to the northern wall of the
proposed classroom due to the canopy of the Oak tree.
10.2 With the large Oak in such proximity to the site an accumulation of leaf litter and
fruit mast will be unavoidable. This situation already exists and has been managed in
the past by onsite maintenance staff. Covers over guttering etc would also mitigate
against this problem without having to do any works to the tree.
10.3 The remnant hedging of Laurel, Hawthorn and Beech is in poor unmanaged condition
with substantial gaps. If windows are to be sighted facing this direct (we have no
information on this at present) then this hedge will acquire a greater significance as
screening for the adjacent farmhouse. If this is the case the hedge should be
improved with planting in the gaps and annual maintenance .
11. IMPACT
IMPACT OF DEVELOPMENT ON THE
TREES
11.1 To carry out the demolition and installation as proposed some minor pruning should
be carried out to the overhanging crown on the Oak tree T1 to give 2.00m clearance
from the building to prevent impact damage in the crown causing more serious
damage. All works should be carried out to BS3998 by trained and experienced
operators.
11.2 The Root Protection Area has been positioned in view of the compacted stone
surface to the north of the building and its current usage as a storage area and
vehicle access into the adjacent building (see Appendix II photo 1 & 2). However
should excavations be required within the stoned area and residual roots are found
to be present then the contractor should use NJUG 10 Guidelines for the Planning,
Installation and Maintenance of Utility Services in Proximity to Trees as best practice
in how to proceed.
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12. CONCLUSION
CONCLUSION
12.1 With the layout as proposed there should not be a significant conflict between
demolition and construction of the new classroom on the existing footprint.
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APPENDIX I
TREE CONSTRAINTS PLAN (extract of an AutoCAD file sent separately as there is too much
information for 1 A4 page.)
This is a design tool only to enable designers and architects to be aware of
‘potential’ conflict with existing trees.
KEY:
SHAPES INDICATIVE OF STEM LOCATIONS
SHAPES INDICATIVE OF CROWN SPREADS (Measured at four
cardinal points).
001
002
003
CATEGORY ‘C’ TREES
CATEGORY ‘U’ TREES
CATEGORY ‘B’ TREES
ROOT PROTECTION AREAS AS PRESCRIBED BY BS5837;
Suggested location for protective barrier.
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STANDON BOWERS, SCC -NOVEMBER 2012 Page 19 of 20
APPENDIX II
Photo 1
looking south west. (T1 Oak in the centre of the picture and site to the left).
Photo 2 Looking north west to base of T1 Oak and loose stone storage area in front.
STANDON BOWERS, SCC -NOVEMBER 2012 Page 20 of 20