THE MELBOURNE RD VETERAN OAK 1.5yr+ RIP
The Melbourne Road veteran Oak (Streets Ahead Ref: 1105291) grew in Stocksbridge, Sheffield, at the upper end of an alley between houses on Oaks Avenue and Woolley Road (OS Grid Ref: SK 262 984). Professor Ian Rotherham has reported that the tree was 450 years old:
The Council’s PFI contractor – Amey – noticed Laetiporus sulphureus (Ls) brackets (Chicken-of-the-Woods fungus) on the lower trunk of the tree and decided that their presence was sufficient to justify felling on the basis that the tree was diseased. Amey posted a felling notice on the tree stating that the tree “…needs to be removed…” because “The tree has decay or disease”. It also stated: “This tree has been professionally inspected”. The tree was felled on Monday, 1st April, 2014. It was one of the oldest highway trees in Sheffield (possibly the oldest).
On 27th January, 2014, the tree was assessed by Tim Wetherhill (Tech Arbor A) – an arboricultural “consultant” commissioned by Amey. The diameter of the trunk at 1.3m above ground was 125.7cm. Tree height was recorded as 13m. Sonic tomography (PiCUS®) was used to “scan” three cross sections of the trunk: “to establish the extent of decay present in the lower stem”. Scans were at 50cm; 75cm & 1m above ground.
To quote from the “Report Summary” of Mr Wetherhill’s report:
“The results of the Tomography indicate that the extent of decay did not breach t/R ratio of 30/70%, the point at which fully-crowned trees become dangerous (in hollow tree stems, the t/R ratio is the ratio of the thickness (t) of sound wood to the radius (R) of the stem. A criterion helpful in evaluating tree risk).”
It is worth noting that a competent independent arboriculturist advised Streets Ahead, on 25th January, 2014:
“…you should now be considering employment of more advanced investigative techniques to assess the tree, if you wish to demonstrate that you have been reasonable in consideration of local opposition to felling”.
A response was received (Ref: 101001211318) from Streets Ahead on 13th February, 2014
(Please note that when this response was issued, Streets Ahead had secretly received the completed investigation assessment and report and had decided to ignore the findings. The “Report Summary” was made available on 26th April, 2014 – three months after assessment, and after felling – by the Cabinet Member for Environment, Recycling and Streetscene, after many repeated requests):
“Dear Sir or Madam
Thank you for your email dated 25 January 2014. We are sorry for the delay in responding.
Thank you for your observations.
The tree to which you refer was found to be infected with Laetiporus sulphurous [sic] (LS). Given the tree’s location, within the carriageway, and, therefore, contrary to section 96 of the Highways Act 1980 and also the nature of decay associated with LS, a decision to fell the tree was made.
However, due to public reaction, and the prominent nature of the tree and its associated amenity value, further investigation has been arranged i.e. Picus tomography. The results of which will enable our Arboriculture Asset Management team to evaluate more accurately the extent of decay and, possibly, offer an alternative management option.”
FEAR, RISK, LIABILITY & COMPETENCE
When assessing veteran/heritage trees, it is important to keep in mind current national guidance:
“Laetiporus sulphureus (Figure 15) break down only the dead wood. This decays the centre of the tree but leaves the outer, living layers intact. While this may not be desirable from the point of view of a commercial forester, the tree is not harmed and may actually benefit. …A hollow tube may respond differently from a solid trunk in high winds and not necessarily more likely to snap provided its walls are not so thin that buckling occurs”.
(Read, 2000, p. 33)
NOTE 2 Some attempts have been made to introduce desired species of decay fungi (e.g. Laetiporus sulphureus) into veteranization wounds. The decay produced by such fungi provides good habitats and tends not to shorten the life of the tree by extending into functional sapwood.”
(The British Standards Institution, 2010)
“Durable heartwood. The heartwood of some species (e.g. the native oaks of the UK) contains protective substances (extractives), which slow down the decay process and sometimes make the wood available only to specialised heart-rot fungi (e.g. Chicken of the Woods Laetiporus sulphureus in the heartwood of oak). In many cases, the continuing growth of sapwood, which eventually becomes new heartwood, seems to keep pace with the spread of decay for centuries.”
(Lonsdale, 2013, p. 16)
“the decay fungus Laetiporus sulphureus: an important provider of habitats for rare invertebrates, in its fruit bodies and in the brown-rot (red-rot) that it produces.”
(Lonsdale, 2013, p. 129)
“WHAT IS A DEFECT?
The term ‘defect’ can be misleading, as the significance of structural deformities in trees (variations from a perceived norm) can be extremely variable. Indeed, deformities can be a response to internal hollowing or decay, compensating for loss of wood strength and providing mechanical advantage, allowing the tree to adapt to wind and gravitational forces. With inadequate understanding, so-called defects may be erroneously confused with hazards and, furthermore, hazards with risk – so unless the risk of harm arising from a hazard is properly taken account of, management can be seriously misinformed, potentially leading to costly and unnecessary intervention.
NTSG definition: ‘a defect in the context of the growing environment of a tree is a structural, health or environmental condition that could predispose a tree to failure’”.
(The National Tree Safety Group, 2011, p. 44)
“OBVIOUS FEATURES THAT MAY INDICATE STRUCTURAL FAILURE
it is inappropriate to react to tree defects as though they are all immediately hazardous. Growth deformities and other defects do not necessarily indicate structural weakness. When noting features that might indicate a likelihood of weakness or collapse, it is important that concern for risk of failure is restricted to events likely in the near future. Trees exhibit a wide range of such features, and the scope for interpreting their significance is complex, particularly when considering the likelihood of non-immediate failure. For example, anomalies in tree growth may indicate internal decay and hollowing; but anomalies in form may be attributable to the tree having compensated for the decay, by mechanically adapting to natural processes.”
(The National Tree Safety Group, 2011, p. 54)
Lonsdale, D., ed., 2013. Ancient And Other Veteran Trees: Further Guidance on Management. London: The Tree Council.
Read, H., 2000. Veteran Trees: A guide to good management (IN13). Peterborough: English Nature.
The British Standards Institution, 2010. British Standard 3998:2010 Tree Work – Recommendations. London: BSI Standards Ltd.
The National Tree Safety Group, 2011. Common Sense Risk Management of Trees: Guidance on trees and public safety in the UK for owners, managers and advisers. Forestry Commission Stock Code: FCMS024 ed. Edinburgh: Forestry Commission.
From: Scott Jack (CLLR) [mailto:Jack.Scott@sheffield.gov.uk]
Sent: 26 April 2014 23:39
Cc: Wain David
Subject: Melbourne Road Oak
As discussed previously, please find attached the report concerning the Oak on Melbourne Road. I’m sure David Wain will be able to answer any technical questions that might arise.
Councillor Jack Scott
Cabinet Member for Environment, Recycling and Streetscene
Councillor for Arbourthorne Ward
PA: Deborah.Hallam@sheffield.gov.uk / 0114 2735794
From: Scott Jack (LAB-CLLR) [mailto:Jack.Scott@sheffield.gov.uk]
Sent: 18 August 2014 08:35
Cc: Wain David
Subject: Re: Our Ref: 101001211318 – Tree – Melbourne Road_Veteran Tree Policy_Hazard Assessment_Risk Assessment_Risk Management_Still no answers, >three months on. 😦
During our exchange, I think it’s fair to say that we haven’t seen eye to eye. I understand your view about the Melbourne Oak tree and I respect it.
I’ve looked back over our emails and I believe we’ve covered the points you’ve raised, particularly concerning tomograms, TEMPO and Howard Baxter’s comments. I’m sorry if you feel this isn’t the case, which is why I’ve tasked David with concluding any outstanding technical questions.
I don’t think it’s fair to charcterise the emails I’ve sent as being fobbed off, and the fact the tree was forged in to two beautiful pieces of art within the school makes clear how important our heritage and this part of the city are.
David Wain: SCC Environmental Technical Officer
Sheffield City Council,