BACKGROUND
7.
Making of Order
An application (including a copy of the engineer's report) to remove 3
of the trees now protected by TPO / 2002 / 24, and several other smaller
younger trees at the western end of Coburg Court, was received on 6th June
2002, on the grounds of subsidence damage to the building.
However consent was refused to remove the 3 large mature holm oaks,
because the Tree & Landscape Officer did not believe that evidence had been
provided to show that the trees were the main factor in the subsidence - in the
engineer's report, a leaking drain was considered to be the main cause of the
damage. However consent was granted to remove the young holm oaks growing below
the mature holm oaks.
The trees form part of an avenue, probably planted in the 19th century, and which is still almost unbroken outside Acorn Gardens. The holm oaks at Acorn Gardens were protected by a Tree Preservation Order in 1993 (reference TPO / 1993 / 39), but at the time of the application the trees at Coburg Court were only protected by a condition attached to planning permission reference TCP / 17910. Central government guidance is clear that planning conditions should not be used for long-term protection of trees, when Tree Preservation Orders are expressly designed for that purpose.
An Order was therefore made on 23rd September 2002 to protect 10 trees
alongside Victoria Grove: 5 holm oaks at Coburg Court and 4 holm oaks at
Cockerell Rise, which partially continue the avenue to the west; and an oak in
the grounds of Cockerell Rise.
The grounds for making the Order were: 'The trees are of high present
and future amenity value and are visible from Victoria Grove and York Avenue.
They are also important as a wildlife habitat, especially for birds and
potentially for squirrels.'
8.
Further applications to remove trees
Further letters were received:
1 letter from the original applicant, dated 29th August, and including a
letter from a tree consultant, dated 15th July;
2 letters from the loss adjuster, dated 10th October and 29th October;
1 letter from the engineer, dated 24th January 2003.
The letter from the tree consultant did not provide any additional
information or reasoned argument to explain their belief that the trees should
be removed, and consent was again refused on 4th September 2002. Consent to
remove the younger trees was confirmed.
The letters from the loss adjuster similarly did not provide any further
evidence or adequate reasoning for removing the trees. The letter dated 10th
October stated ' ... partial construction is now inevitable. This means that the Buildings Insurers of
Coburg Court will face substantial increases in costs.... if you were to
reconsider this matter and consent to the removal of all of the trees, this may
well impact upon the replacement foundation depth for the reconstructed part of
the structure and thus there is still an opportunity to apply common sense and
reduce repair costs. If the trees remain then any foundation scheme must be
designed to allow for the mature height of the trees, thus increasing costs
even further.'
The reply dated 24th October 2002 pointed out that '... since, whatever
the cause of the damage, the foundations will be underpinned, I remain to be
convinced that it will be necessary to remove the 3 mature holm oaks.' The
letter also referred again to the consent to remove younger trees: 'The holm oaks protected by the TPO are
mature trees and I would not expect their water uptake to increase markedly in
future years; while the other holm oaks, which could be removed under the
consent already granted, are younger trees and I would expect them to increase
their water uptake as they grow. My consent was therefore in line with the
advice given by BRE Digest 298 (April 1999) "Low-rise building
foundations: the influence of trees in clay soils".'.
The reply from the loss adjuster dated 29th October 2002 stated '... If a new building was to be constructed on this site, without any trees to consider, then excavations to the existing foundation depth would be adequate. Therefore, without trees, as the foundation would be no deeper, there can be no justification to underpin. Therefore, the nuisance trees must be removed to avoid unnecessary expenditure.'
The reply dated 7th November 2002 stated '... the trees are there, and
they were there when the building was built. The building regulations at the
time might have been complied with, but if building regulations current now
would require deeper foundations, then I do not see why these should not be
provided now (in the form of underpinning), just as they would be for a new
building.'
The engineer's letter dated 24th January 2003 requests consent to remove
4 trees, T1 - T4, and states ' ... The opening of cracks in late Summer/Autumn
2002 has been followed by an initial closing of cracks which appears to be
accelerating with the increased wet weather. This behaviour is highly
characteristic of damage caused by shrinkage of clay subsoil, and while I do
not discount the contribution of other factors, I am now of the opinion that the
Holm Oak trees on the roadside, Tree Nos. T1 to T4 on the plan accompanying TPO
No.24 2002, opposite this damage have played a significant role in causing this
damage, and that as the trees remain they will contribute to significant
worsening of this damage in the longer term, in terms of its extent and
magnitude....'
Unfortunately the letter was not accompanied by a revised report
including the latest figures such as the monitoring of the cracks over the time
since the last report, so it is not possible to follow the evidence or
reasoning which has led to this belief, though certainly the cracks are much
wider than they were at the time of the initial report and application.
In any case, as repairs to the foundations will be necessary, it is still arguable that they should include deepening (underpinning) which would allow the trees to remain. In addition, no advantage has been taken of the consent to remove the younger trees, which would have provided an opportunity to monitor any difference following their removal.
If consent is refused at this stage, and the Order is confirmed without
modifications, it would still be open to the owners or their agents to apply
for removal of the trees, and if clear evidence and reasoning for removal were
provided, consent could still be granted at that stage.
FURTHER
COMMENTS AFTER 28TH FEBRUARY 2003
9.
Further legal comments have not been
received.
10.
Further written engineering comments have
not been received, as there is no IWC Engineer employed to give advice in such circumstances,
and the tree section has no budget available for engineering consultancy.
11.
However, further desktop studies taking into
account local knowledge have revealed that:
$
The geological map of the Isle of Wight indicates
underlying soils to this site are plateau gravels, which do not reflect
information from boreholes & trial holes;
$
Historical 19th Ordnance Survey maps
indicate the site was within old gravel pit extractions. This would suggest
soils are imported fill materials.
12.
If this is confirmed, it would seem
reasonable to suggest that the trees are not the main cause of the subsidence.
13.
It may well be the case that underlying
ground water levels vary significantly during the year, resulting in volumetric
changes in clay soils.
14.
OPTIONS
EITHER
Grant consent to remove T1 - T4, and confirm TPO / 2002 / 24 with modifications to exclude T1 - T3, but with a replacement holm oak tree for T4 to be planted between T4 & T5.
OR
Refuse consent to remove T1 - T4, and confirm TPO / 2002 / 24 without modifications.
If the order is confirmed without modifications, it will ensure the continued existence of the trees for the immediate future.
If consent is granted to remove 4 trees, and the order is confirmed with modifications, it will set a bad precedent of allowing financial considerations to come before landscape or environmental considerations.
If the order is not confirmed, trees T1 - T4 would be removed, and the other trees might be under threat.
RECOMMENDATION
Refuse consent to remove T1 - T4, and
confirm TPO / 2002 / 24 without modifications
BACKGROUND
DOCUMENTS
1.
Planning permission for Coburg Court reference TCP / 17910.
2.
Tree Preservation Order TPO / 1993 / 39.
3.
BRE Digest 298 (April 1999) "Low-rise building
foundations: the influence of trees in clay soils".
4.
Application for works to trees at Coburg Court received 6th June 2002 [including
copy of engineer's report reference 12443/D/001/R/RTW/WW - see 12 below].
5.
Letter refusing consent to remove 3 mature holm oaks
at Coburg Court dated 30th July 2002.
6.
Application for works to trees at Coburg Court
received 30th August 2002, including letter from tree consultant dated 15th
July 2002.
7.
Letter refusing consent to remove 3 mature holm oaks at Coburg Court
dated 4th September 2002.
8.
Tree Preservation Order TPO / 2002 / 24 made 23rd September 2002.
9.
Letter from loss adjuster, dated 10th October 2002, received 15th
October 2002.
10.
Letter in reply to loss adjuster dated 24th October 2002.
11.
Letter from loss adjuster, dated 29th October 2002,
received 31st October 2002.
12.
Letter in reply to loss adjuster dated 7th November
2002.
13.
Letter from engineer, dated 24th January 2003,
received 28th January 2003, and including copy of original report reference
12443/D/001/R/RTW/WW.
Further
background documents added since 28th February 2002:
14.
Copied extract of 1866 Ordnance Survey map.
15.
Copied extract of 1939 Ordnance Survey map without
buildings on site.
16.
Copied extract of 1939 Ordnance Survey map showing
buildings on site.
17.
Copied extract of 1976 British Geological Survey map.
Contact Point : , Rowan Adams F 823559
M J A
FISHER
Strategic Director of
Environment Services
