What the experts say

In January 2017 Jeremy Barrell (BSc FArborA DipArb CBiol FICFor FRICS) appeared on ‘The One Show’ defending Sheffield’s healthy highway trees.

Jeremy followed this up with an article in February 2017: Tree benefits; the missing part of the street tree cost benefit analysis equation’, published by the Institute of Chartered Foresters. In it he says:

“Sheffield was widely hailed as one of Europe’s greenest cities, but it is rapidly gaining an international reputation as the place where they are felling street trees on an industrial scale. Local democracy seems to be unravelling before an international audience as the wishes of local communities are ignored and healthy trees with decades of life left in them are felled causing significant loss of tree benefits. It is a political problem and it will be for the politicians to find a solution, with issues way beyond the remit for tree experts to resolve. However, in the melee for the high ground, tree management principles are being misapplied as Sheffield City Council clamours to justify its actions, and that certainly is a matter where tree professionals can assert authority.”

The graph at the end of the article was included in Jeremy’s presentation to the 2017 STAG conference. It illustrates the actual lifespan of street trees and is included in our tree life expectancy leaflet. At the conference, Jeremy summed up the entire situation with the phrase: “PFI contracts don’t work for trees.”


Professor Ian Rotherham, of the Department of the Natural and Built Environment at Sheffield Hallam University, has been an advocate for the city’s street trees from early on in the campaign. In a statement given recently to STAG he said:

“I have described the current situation as ‘The Sheffield Trees debacle’ and as ‘an avoidable crisis‘. Indeed, before the present situation unfolded, having had concerns raised by local people, I went to meet with Amey to see if ways could be found to make this a more positive, beneficial and inclusive process for Sheffield communities and the Sheffield environment. I came away from the meeting with platitudes, excuses, and intransigence in terms of any review of position or process. Blithely unaware of any of the city’s commitments or polices on ecology, community or the environment, it was clear that both Amey and SCC were determined to press ahead with a thoroughly damaging, expensive and undemocratic assault on the city’s highway trees. The scale of this misapplication of funds and resources becomes more apparent with the misuse of the original consultant’s SCC-commissioned review – which recommended a maximum of 500 trees to be in need of removal, when after only 3 years or so, over 5,000 had been felled. This represents a catastrophic undermining of local environmental democracy, of local sustainability, and of planning for climate mitigation, for biodiversity and for community health and welfare – and is on an unprecedented scale.”


The University of Sheffield’s Landscape Department have issued a statement regarding the future of the city’s urban woodland on their blog.  It includes the following:

“We believe that a stronger urban tree strategy for Sheffield can be developed organically with the good will of Sheffield residents when it is accompanied by a well-rounded and open assessment of the benefits and disadvantages of urban trees and supported by the latest research in urban forestry and landscape architecture.”

The draft version of SCC’s Trees and Woodlands Strategy 2016-2030 was read by landscape department staff, and suggestions were made, however this consultation document remains unfinished.


‘Sheffield Street Trees’ was compiled by Ian Dalton, Tree Officer for the London Borough of Bromley, after he visited the city in March 2017. Ian is an experienced arborist qualified to Dip ArbLevel 4 who has been employed in the arboriculture industry for 16 years. He concludes that good arboricultural practices are not being followed, standard engineering solutions are not being employed and that many of Sheffield’s trees are being felled unnecessarily.

Ian has since compiled the insightful CAVAT valuation report on Street Trees in Sheffield (note: 8MB download).  The data was gathered from across the city by a keen group of ‘citizen scientists’ who carefully measured each threatened tree. The results speak for themselves: by the end of 2017 SCC will have destroyed £60 million’s worth of healthy street trees.


‘Regarding trees in Nether Edge, Sheffield’ is a report written by Peter Townsend, BSc CEng MICE, a highway engineer with many years experience delivering similar Local Authority contracts to the current ‘Streets Ahead’ programme.

Peter, a Sheffield resident, has had plenty of opportunities to observe the city’s street trees, and he believes many of those that are currently condemned could be retained.


“Well Managed Highway InfrastructureIn October 2016 the UK Roads Liaison Group published the Department for Transport commissioned document ‘Well-managed highway infrastructure: a code’.  It contains guidance that is particularly relevant considering the Council’s rigid attitude towards accommodating tree roots within pavement surfaces. Under Section B.5.46 it states:  

‘…extensive root growth from larger trees can cause significant damage to the surface of footways, particularly in urban areas. A risk assessment should therefore be undertaken with specialist arboricultural advice on the most appropriate course of action, if possible to avoid harm to the tree. In these circumstances, it may be difficult for authorities to reconcile their responsibility for surface regularity, with wider environmental considerations and a reduced level of regularity may be acceptable’.


Steve Frazer, CMLI, is Principal Landscape Architect at Enzygo Ltd, Sheffield.  He has written a piece on Sheffield’s street trees for the Landscape Institute blog, in which he concludes:

“The Streets Ahead project is truthfully a highway project focused upon delivering smooth tarmac, despite the environmental claims otherwise. It was likely formed with the best of intentions to solve a single perceived problem, that of potholes, but the objectives and mechanisms for delivery derive from a narrow perspective, that of highway engineers and councillors. I am certainly not criticising highway engineers, but I am emphatically criticising silo working, as it can offer only a narrow view for what is important, does not embrace collaboration and therefore does not exploit design opportunity.

For Sheffield to have achieved a better outcome, I believe they needed a bolder vision, which appreciated the potential of a street in its broadest sense, recognised and pursued by a multidisciplinary team that understood the existing assets. And of course, these proposals should have been developed alongside the citizens of Sheffield to ensure that the project reflected community interests, promoting real engagement and ownership. These feel like relatively modest aspirations given the scale of the project.

However, the reality is that Sheffield feels like a big opportunity missed, with the Streets Ahead programme an ironic title falling woefully short of its potential. As a consequence, the public will has been frustrated, the council have suffered tremendous damage to their reputation and the city will bear a poorer environment. Perhaps a tough lesson on narrow ambitions meted out to Sheffield, but hopefully learnt by others.”


“Well Managed Highway Infrastructure

In August 2017, the Sheffield Society of Architects was moved to write to Cllr. Julie Dore about the fate of the city’s street trees.  Here is the letter reproduced in full:

“We are becoming increasingly concerned about the negative effects that the Streets Ahead contract is having on Sheffield’s built and natural environment, including the impact on the ability of the city’s trees to reduce pollution, provide habitats for wildlife, provide shade, and amenity value.

As built environment professionals, we often work closely with landscape architects, urban designers and other specialists, and understand how important landscaping is to residential areas, particularly in the urban environment.

As cities become denser and more crowded the effect of trees and other landscaping is critical to the physical and mental wellbeing of the inhabitants.  The overwhelming evidence of the positive social and environmental impact of urban trees, and particularly street trees, is well documented in numerous publications and reports, including those by Trees for Cities, The Forestry Commission and Natural England.

We understand and accept reasons for felling badly damaged or diseased trees, but we do not believe there are acceptable reasons why trees that are healthy and have many decades of life left are being felled now. Problems with ground surfaces around tree roots can easily be dealt with by the correct technical detailing of the surrounding build-up.  Typical technical solutions have been drawn up and sent to the Working Party – although similar solutions are already outlined by the Council in the Streets Ahead 5 Year Tree Management Strategy, which includes engineering and alternative options that should be considered in order to retain trees (section 3.2, page 11). The Strategy also confirms that these proposals would require ‘no additional funding’ from the council. As these solutions are set out in Streets Ahead’s own document, they must fall within the contract between the Council and Amey and therefore can and should be implemented in preference of felling.

Nationally recognised arborists have reviewed the condition of the threatened trees and have confirmed that were the solutions outlined above to be implemented, the majority of the threatened trees could be retained.

Whilst we recognise that felled trees are to be replaced, we are of the opinion that although the chosen species may reduce issues such as sap drip, even when mature the replacement trees will not have the same stature, environmental benefits or aesthetic appeal as the originals, particularly where they are sited well away from the current location. A better compromise is possible and must be found.

ARUP landscape architects report, ‘The benefits of large species trees in urban landscapes: a costing, design and management guide,’ shows that the annual net benefit of planting large species of trees is 92% greater than for small species. It also outlined the financial, social and environmental benefits of large tree species, and how they be successfully retained and planted in urban environments. Rather than remove mature trees and replace with small-species saplings, it of course makes the most financial, social and environmental sense to retain large mature trees wherever possible.

The 2011 report, ‘Torbay’s Urban Forest: Assessing Urban Forest Effects and Values’, concluded that the structural asset of their trees was worth a remarkable £280millon. Sheffield is well known as being a green, leafy city and its trees will also undoubtedly have a significant financial value.

Whilst we understand that street trees make up a small percentage of Sheffield’s overall tree cover, we recognise the special importance of large street trees, and are therefore increasingly worried about the negative impact of the current implementation of the Streets Ahead contract. Notwithstanding the disturbing content of the tree works, the often bizarre phasing of works to trees and neighbouring roads/footpaths, and numerous examples of potential health and safety breaches also lead us to conclude the contract is not being delivered in a manner deserving of this great city.  We therefore urge the council to review the contract and act in the strongest terms in the interest of the city (and beyond) to ensure street works are administered in a safe, neighbourly manner, including the cessation of tree felling and preference for retention.”

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