Decision details

The Cabinet Member:  

1.    Noted that the advice the Council has received from the ‘third expert’ (Ian Brett-Pitt of Brett-Pitt Associates Ltd) is that the damage that has occurred is “probably caused by root induced subsidence” and that “we do not believe there is any evidence which shows the damage was caused by heave movement”.  

2.    Noted that Ian Brett-Pitt includes a view that “it is not possible to conclude that roots from T2 have caused and will continue to cause subsidence to nearby property in Barnard Way” (Conclusion C) and “any decision to remove/retain T2 should be predicated on recent/current evidence of movement and subsidence” (Conclusion H). In essence, the view of this expert is that categorical proof that T2 has, and will continue to, cause the damage, is not yet possible.  

3.    Noted that the original expert advice PCC received (Mr P Harris advice), as previously published to Cabinet, noted “oak tree roots have been found beneath the foundations” and “T2 is very substantially larger than T1. The extent of its roots would be expected to encompass most, if not all, of the footprint of this house (and the adjacent one, 10 Barnard Way)”, and “so long as roots continue to extract moisture from beneath this house there will be continued seasonal subsidence with associated damage”. Consequently, it should be noted that the difference of opinion between these two experts is that one seeks more definitive proof whilst the other uses the available evidence to determine a cause. 

4.    Noted the typical cost of installing a root barrier in this case would be “around £30,000 per property” (excluding any potential compensation costs, and assuming “the owners are prepared to allow appropriate and necessary access mindful of the inevitable disruption and inconvenience that will arise”) 

5.    Noted the estimated cost by Ian Brett-Pitt of underpinning costs are “in the region of £150,000 for each property” 

6.    Noted that the advice of Ian Brett-Pitt is that five realistic options are available to PCC (see his response to Q2 in his report), each of which he describes as having varying degrees of cost, risk and amenity impact, but the options in short are: 

a)    Removal of T2 

b)    Retaining T2 but with PCC meeting the costs of underpinning to any affected properties 

c)    Retaining T2 but with PCC meeting the costs of a root barrier to be constructed in the rear gardens of any affected properties  

d)    Retaining T2 but with PCC undertaking a 70% Hortlink compliant management and control of T2 i.e. 70%+ crown volume reduction followed by biennial pruning 

e)    Retaining T2 but with PCC undertaking a 40%+ Hortlink compliant management and control of T2 coupled with a suitable root barrier as per C & D above. i.e. 40%+ crown volume reduction followed by biennial pruning and the construction of a root barrier across the rear gardens of all affected properties. 

7.    Note that in considering the options available, officers have had to apply a judgement, balancing a wide range of issues, including professional expertise (arboriculture, structural engineering, insurance, landscape, environment, biodiversity and more) as well as taking consideration of the corporate financial situation.  

8.    Note that the position taken by the Insurance company representing the homeowners affected is that a root barrier is not a feasible option, meaning the deliverability of such a solution is now very low. 

9.    Note that, in the opinion of officers, the view remains that the only effective way to legally discharge our duty to abate the nuisance and to implement an affordable solution is the felling of the tree.  

10.  Agree to the felling of the tree, together with?provision of 100 oak trees (‘feathered’ nursery stock, c2m high) to be planted across the city, as a contribution towards mitigating the loss of the oak tree remains the most appropriate solution having made a balanced judgement on this difficult decision. 

The Cabinet Member needs to decide whether proceeding to fell the tree is the most appropriate course of action, when considering all options and taking account of all harm and costs of such options. 

The options are set out in the various papers attached and presented to cabinet, but in summary: 

1.     to install root barriers – high risk of failure, despite considerable cost, and not under the control of the council to implement.  

2.    to prune the tree (and regularly prune thereafter) - not generally effective, unless extensive and frequent, negating the amenity value of the tree. Even with frequent pruning, risk remains. Relatively low cost, albeit ongoing annual (or so) costs.  

3.    to do nothing – not legally an available option. We are duty bound to abate the nuisance.  

4.    to accept liability and costs associated with underpinning properties affected. Effective, but very expensive, and not covered by insurance.  

5.    to fell the tree – effective at abating the nuisance, and low cost, though obviously the tree is lost in its entirety 

6.    A clone can be made of the tree for replanting like the Newton Tree in the Cambridge Botanical Gardens as a legacy. 

None.

Agenda item - 'Save Bretton Oak Tree' Petition - Action to be Taken | Peterborough City Council