Mike Ellison’s response to Newcastle City Council 20.1.2012
I received a letter from Mike Ellison today. It’s a response to a memo from Newcastle City Council which critiqued his Laman Street report. It remains bizarre to me that we think we can just dismiss the assessment of someone as eminent as Mr Ellison.You can read his letter by clicking here Mike Ellison response to Cordingley 6502-L1-12 or you can keep going where it’s reproduced below.
You can read the Council memo here:
Dr Caitlin Raschke
Save Our Figs Inc.
PO Box 155, Islington, NSW 2296
Our Ref:CW/6502-L1 18 January 2012
NEWCASTLE CITY COUNCIL.
INTERNAL MEMO OF FRANK CORDINGLEY –
SUBJECT: MIKE ELLISON REPORT
I have read the above memo, which was issued on 16 January and would like to respond to the somewhat hollow criticisms that are referred to as comments about my report CW/6502-R-12. Mr Cordingley’s comments are below in underlined italics followed by my responses.
Comments relating to my report.
“The report does not appear to take into account the unique situation in Laman Street. The Laman Street figs are not typical – they have a crown height of 24 metres, a crown width of 25 metres but with severely restricted root plates.”
My report takes full account of the situation, and in particular the growing conditions of the trees being in an elevated location close to the coast and more importantly the geological conditions and how they are likely to influence rooting and stability of the trees. Geology is barely accounted for in the tree-specific investigations commissioned by the Council. More importantly, the Council’s assertion that the root-plates of the trees are asymmetrical is founded on a very limited investigation, which excavated to depths of just below one metre on one side of the trees only. How this investigation can be used to justify the Council’s statement that the trees have ‘severely restricted root plates’ or asymmetrical root-plates eludes me.
“Each tree appears to have been assessed as if it was in isolation. Council believes the trees should be considered as a collective due to their interlocking canopy.” and “The report expresses the opinion there are no high risks resulting from crown asymmetry but fails to substantiate this.
” My report considers fully the protection that trees are afforded by their neighbours and the ’closed canopy’, as I refer to it. My consideration of the increased risk, where the support of neighbouring trees has been removed by the Council, is actually quantified in my survey schedule and described in the report thus: “My assessment has revealed no concerns in this regard, and even with the removal of trees A, D and E, there are no high risks resulting from crown asymmetry.” That the risks are low is substantiated by my risk assessment.
“The report acknowledges that the trees have been repeatedly damaged by utility work but doesn’t appear to detail that damage or factor it into the assessment contained in the report.”
I not only make reference to the damage, but state “and I have taken account of this in my risk assessment”.
In consideration of damage, I take account of the observations and opinions of two other arborists, one of whom was employed by the Council and upon whose opinions the Council relies to support its own position (e.g. 6.5.2 of my report). Additionally, I make it clear that “In consideration of my own findings and the factual observations of others, I believe that my assessment of the risks from the trees has been sufficient to inform their reasonable risk management”.
“The report expresses the opinion that the fig trees are highly likely to have deep roots based on the ground conditions that the report states are conducive to root growing. This opinion does not appear to be substantiated with evidence .” The evidence is cited in my report, and was in part provided by the Council’s own consultants but more importantly through reference to published research (see 6.6.3, 6.6.4 and fig. 1 of my report).
“The report expresses the opinion that there is nothing wrong with the branch systems of the trees. This opinion does not appear to be substantiated with evidence.” The report does nothing of the sort. I quote: “I identified no significant defects or signs of significant structural weakness in the tree stems other than the primary branch attachments with compression forks discussed above at 6.2.2.” and “Although there is evidence of localised adaptive growth, I have not identified any significant signs of failure in these compression forks or otherwise in the attachments of branches. I have taken full account of these features in my risk assessments.” Additionally, at 5.4.3, in relation to Visual Tree Assessment, I make appropriate reference to the structural self-optimisation of trees and their adaptive growth, which obviates the need for the reporting of every potential growth anomaly.
Other comments in the memo
It is suggested that “Council’s extensive body of evidence shows the figs pose a significant risk to life and property and, as a responsible organisation, Council cannot simply ignore this information.” If this is a reference to the Council’s ‘Case Studies’ document, this is nothing more than a record of tree failures, the causes of which are not known, but of which some possible contributing factors (such as restricted rooting) have been identified. There is no record of the magnitude or frequency of wind-loading that resulted in the recorded failures and as such the records have no value in informing consideration of the Laman Street trees. This document is a catalogue of assumptions.
I cannot leave the quoted statistics of historical tree failure without a mention for no reason other than the Council might infer that I accept them. I do not.
I find it disturbing that those affected by the proposed removal of the Laman Street fig trees might be bamboozled by Mr Cordingley’s interpretation of my report and trust that you will publish this letter on your organisation’s website by way of clarification.