Two highways matters

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Sadly another local tree needs removing.

This is what TFL have told me:

TFL will be undertaking works to removal a plane tree outside of 341 on Kennington Road. The works to remove the tree are programmed to be completed within the next 6-8 weeks. We would be grateful if you could inform any others within Lambeth Council you believe should to be aware of this decision. We will be installing a notice on the tree at least 10 days before the removal to inform members of the public of TFL decision and planned works. Any enquiries you receive can be directed to TfL Helpline telephone number:  0343 222 1234 or the TfL contact form:

https://tfl.gov.uk/help-and-contact/contact-us-about-streets-and-other-road-issues

The visual assessment of the physiological condition appears to indicate that the tree is in a fair condition but the notable defect is the cambium wound which progresses vertically from the lower canopy to the base of the tree on the north western side where a cavity has developed at the base.

Following last year’s annual defect survey, it was recommended to undertaken further decay detection in order ascertain the extent and risk the wound posed. The resistograph method was adopted in this instance and undertaken on the 15th of April 2020. For those unfamiliar, this device is used to establish the structural integrity of the internal wood structure i.e. its density and provides an output of resistance i.e. how much force is required for the drill bit to progress through the wood.

The readings were taken at 500mm above the base of the tree. The results of the restograph indicate that the cavity/decay within the tree is at least 53cm in diameter therefore the residual wall has only a thickness of 12cm. Applying Mattheck’s ratio for eccentric decay columns, the tree has a residual wall thickness of 0.18 based upon of t/R ratio of 12/65. A t/R of 0.18 is lower than the published failure threshold (t/R = 0.3). The effective ‘open cavity’ is less than 1/3rd the circumference of the tree and thus, would need exceed 43.3cm in diameter for this to be a sole consideration in the relative safety factor for this tree.

To concluded, there is a greater risk of complete tree failure as a result of this defect. Therefore to ensure the safety of the Highway it is necessary for TFL to undertaken appropriate action.

We appreciate that the current amenity value of this tree is high; however, to mitigate the risk effectively would remove any amenity value the tree holds within the landscape. TFL do not believe there would be any benefit if this tree were to be a monolith. Given that there are numerous other mature trees within Kennington Rd the overall impact to the amenity of the streetscape will be limited were the tree to be removed and replaced. Replacing the tree also ensures there are no net loss in the street tree numbers, and allows any new tree to replace canopy in time, retain continuity within the character of the streetscape and will also improve the age diversity/resilience within the area.

Therefore, TFL believe the appropriate action is to remove the tree and replace during the next planting season.

And big holes in the ground at Kennington Cross…

In case you were wondering what was happening  this was to try and repair the local gas main. We have, apparently, been affected by low pressure in the area and this was an attempt to find out why.

Cadent, the UK’s largest gas distribution network, discovered that the pipes were in need of replacement and had sometimes become mismatched over the years. They also found some disturbingly loose ends from some of the mains electric cables and street lights.

They will be filling in the holes again but will need to come back again.

Cllr Jon Davies.

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