A Stocksbridge Tree Jan 23rd 2014
If anybody has any complaints regarding tree work done by Amey on behalf of the council, and wants answers from the people directly responsible, you need to contact Amey via the council’s website: https://www.sheffield.gov.uk/roads/works/schemes/streetsaheadproject.html .
You will be prompted to e-mail email@example.com or telephone customer services on: (0114) 2734567.
This is the best way to get answers. Councillors are unfamiliar with the details and at best will just fob you off with general schpeel. They are not knowledgeable or familiar with arboricultural matters. To the best of my knowledge, Sheffield council has not actually formally adopted a specific Tree Strategy. One has been in development for a few years now!
If you are not happy with the answers you get, then contact your councillor. 😉
If anybody would like to get a better idea about Amey’s tree work, I recommend you visit the Stocksbridge Community Forum and type in a key word in to the search box (such as “tree” or “Amey”).
You may find the following document of interest:
The National Tree Safety Group (2011a) Common Sense Risk Management of Trees: Guidance on trees and public safety in the UK for owners, managers and advisers, Edinburgh: Forestry Commission (Forestry Commission stock code: FCM 024).
“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)
The following enquiry response has been issued by Amey:
“The tree to which you refer was found to be infected with Laetiporus sulphurous (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.”
Make of that what you will.
You may find the following document to be of interest:
Read, H., 2000. Veteran Trees: A guide to good management (IN13). Peterborough: English Nature.
“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. Decay and hollowing are part of a nutrient recycling process.The tree can make use of the products of wood decay within the trunk by producing aerial roots from its above ground parts, which grow into the rotting stem. 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)
Excerpts from “BS 3998:2010 Tree work. Recommendations”…
“Notes and commentaries are provided throughout the text of this
standard. Notes give references and additional information that
are important but do not form part of the recommendations.”
From Annex C of the standard:
“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.”
From section 3 of the standard: “Terms and definitions”
“controlled infliction of damage on a tree to achieve a specific habitat
NOTE This is undertaken to promote or emulate the development of
some of the features of a veteran tree, especially the wildlife habitats and
shelters that are provided by decaying wood and cavities (see Veteran
trees: a guide to good management [1*]). When undertaken, it is usually
on young or early-mature trees.”
*This publication referenced here is Read, 2000, as quoted in my previous posting (above).
Just to make it clear to readers, the standard does not condone widespread veteranization practice at every opportunity. A commentary at C.4.2 of the standard states that the purpose of veteranization is “…to encourage the development of decay
and other features characteristic of veteran trees when a major age gap
in the tree population would otherwise lead to a break in the continuity
of the wildlife habitats and shelter provided by such trees, especially in
decaying wood and cavities.
As I understand it, the management plan for Wadsley and Loxley Common prescribes the practice of veteranisation.
I should, perhaps, mention that when an oak gets as old as the Melbourne Road veteran in Stocksbridge the cross-sectional area of its trunk largely consists of “heartwood” (i.e. it largely consists of dead wood). There may only be a few millimetres or a couple of centimetres of sound, living wood (“sapwood”), surrounding the heartwood. Hence the necessity of a detailed inspection by a competent arboriculturist. This should examine the extent of decay and effect of decay on structural integrity, thus permitting both appropriate evaluation of potential hazard and informed risk assessment.
The local paper reported that the tree was felled this Monday (1st April). The stump has been ground out and nothing more remains. Does anyone have a link to the Picus tomograms that Amey commissioned, or any photographs of the logs or stump? It would be interesting to know the extent of the cavity that was present within the tree.
Here’s a link to the newspaper article:
With regard to the report from the detailed inspection (performed on 27th January 2014) of the Melbourne Road veteran oak.
Here are some excerpts from the 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…”
“…the following management options were considered:
A. Removal and replacement if highway safety obligations prevent safe retention in the carriageway.
B. “Heavy” reduction of the existing crown volume (approx.. 30%) and instigation of a long term heritage tree management strategy with annual inspections. The installation of line markings and/or bollards to highlight tree encroachment and guide traffic.
Following much determination, option A was considered most appropriate”.
The recommendation for annual inspection is perhaps a little excessive, given that the tree was apparently healthy; oak is well known to be particularly successful in hindering the spread of microbial infection within its parts; oak is also well known to be successful in compensating for loss of cross-sectional area, through the production of reaction wood (termed “adaptive growth” in the British Standards), which effectively maintains structural integrity (of stem/branch or root), enabling plant parts to have a safety factor greater than that of most mammal bones (Mattheck et al., 1993).
It would appear that the detailed inspection was only commissioned to create the impression that those responsible (both Amey and the Council) were attempting to do things the right way, after initially taking a decision to remove the tree without a necessary and appropriate hazard assessment and subsequent informed risk assessment. To my mind, what has happened has been an appalling and unacceptable waste of taxpayer’s money. It is a shame that those concerned cannot be issued with some form of proportionate financial penalty.
Hopefully, lessons will have been learnt from the appalling way in which the whole process was handled. It is unfortunate that the local community will have to suffer the consequences of a decision making process in which they had no part. Such old veteran trees, particularly oak, are extremely rare along our city streets.
The final decision on the future of the Melbourne Road veteran oak should have been taken by an arboriculturist (as defined within British Standard 3998).
A copy of the tree report has been sent to Cllr A.Brelsford.
Mattheck, C., Bethge, K. & Schafer, J (1993) Safety Factors In Trees. Journal of Theoretical Biology, 165, p.185-89.
We don’t live in a perfect world, and tree managers will always worry about trees with cavities, such as the Melbourne Rd veteran oak. Unfortunately, cavities are likely to be regarded as serious hazards regardless of whether or not they have been risk assessed. For anyone interested in methods used to assess trees with cavities, see the following document (a hand-out from the Kansas Arborists Association Conference):
Luley, C., 2006. Measuring Strength Loss from Decay.
In addition, those interested may wish to see the following document too:
Bond, J., 2006. Foundations of Tree Risk Analysis: Use of the t/R ratio to Evaluate Trunk Failure Potential.
For a little background on the assessment of trees, see the following:
Van Wassenaer, P. & Richardson, M., 2009. A review of tree risk assessment using minimally invasive technologies and two case studies. Arboricultural Journal, Volume 32, pp. 275-292.
Freely available online:
You may be interested to know that the latest guidance on veteran tree management (RRP £30) is now available in PDF format as a free download at the “VETree” (an acronym for ‘Vocational Education and Training on Veteran Trees’) website (once there, you’ll find it listed under “Training products”):
Title: Ancient and other veteran trees: further guidance on management
Editor: David Lonsdale
The publication has been available for download since December, I believe; it updates the guidance and recommendations of the aforementioned publication by Read (2000) and it is referenced a number of times within British Standard 3998 (2010) – Tree work – Recommendations: the standard to which every tree worker should adhere.
VETree was a European project set up by 5 partner organisations that ran from November 2012 to October 2014, with the aim of setting up a European wide quality training programme in veteran tree management.
“…there has also been considerable loss of veteran tree habitat due to ill-informed safety management. The conservation and continuity of old trees in the landscape depends on better informed management, which takes into account their intrinsic values as well as the legal implications of ownership.”
(Read, 2000, p. 2)
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