Council sets the record straight on street trees myths
01 February 2017
Streets Ahead is today setting the record straight on a number of myths around its street tree replacement work.
Councillor Bryan Lodge, Cabinet Member for the Environment at Sheffield City Council, said: “There has been a lot of attention on the street trees replacement work in the Streets Ahead contract. We welcome the passion of the people who care as much as we do about street trees, and have committed to working in a more open and transparent way with affected residents across the city, but we also know that there are a number of myths around the city about the work. We want to take the opportunity to set the record straight on some of these issues.
“We have also committed to getting out into the community to talk to people who have questions about this work. Please get in touch if you run a community group, and would like the opportunity to find out more about the Streets Ahead work.”
Myth 1: Streets Ahead is replacing 20,000 street trees across the city
Truth: The Streets Ahead programme plans to replace approximately 6000 street trees in the first five years (Core Investment Period) of the contract.
All street trees are inspected by qualified professionals every three to five years to identify any works deemed necessary including replacement. Throughout the remainder of the contract, due to natural loss and extreme weather conditions, we believe we will need to replace around 200 trees per year to ensure the health of the city’s tree stock.
The total estimated number of street trees to be replaced, on a one for one basis, over the full 25 year contract period, amounts to less than 0.3% of the city’s overall tree stock.
In addition, Streets Ahead will plant an extra 600 street trees in Sheffield over the contract period meaning ultimately there will be more trees in the city than before the contract started in 2012.
The street tree replacements are supplemented across the City where in recent times an additional 58,000 trees have been planted and 20 new woodlands are being created.
Context: Before the 25 year highway maintenance contract was signed in 2012, many of our roadside trees had been neglected, leading to some of them being removed, usually without replacement, leaving some streets in the city with unmanaged and reduced tree stocks. A further survey in 2012 identified that some trees were dangerous, dead, dying or diseased and also recognised that over time; trees deteriorate and require continuous maintenance. Whilst the surveys identified that the health of street trees in Sheffield was diminishing, they did not take into account those trees which were damaging or blocking the highway. The Streets Ahead contract allows us to prevent a severe decline in the health of Sheffield’s street trees and to maintain and cultivate the city’s iconic tree landscape for generations to come.
Myth 2: It’s cheaper to remove a tree than it is to retain it
Truth: The costs associated with removing an existing tree followed by sourcing, planting and maintaining a replacement are greater than those associated with maintenance of a mature tree. This takes into account a number of factors including inspections and noticing; adherence to the required traffic management recommendations; the removal and disposal of arising’s; pit construction for new tree; purchase of tree and sundries, planting and maintenance for early years such as watering and replacement of any failures/vandalised trees.
Context: The cost of tree replacements under the Streets Ahead contract not only take into account replacing the existing tree but also include maintenance of the tree for the duration of the 25 year contract.
Over time, trees grow and can be affected by changes to their surrounding environment which subsequently can lead to required adaptations to their maintenance programme. These often unforeseen changes, including severe weather and changes to the highway network can now be managed under the Streets Ahead contract to ensure we not only replenish, but maintain our growing street tree stock. The Streets Ahead contract means Sheffield can make an investment in trees now so they can be enjoyed by generations to come. Ultimately, the decision to replace a street tree falls to the Council.
Myth 3: The Streets Ahead contract is preventing engineering solutions being applied
Truth: Streets Ahead has a comprehensive list of engineering solutions that are considered to retain street trees, and many of these have already been used. For example, the digging up of footways for physical root examination prior to an ultimate decision being made was used to retain 3 trees on Rustlings Road in 2016.
Context: Some of the engineering solutions outlined in the contract are highway maintenance related and are as such included in the contract without extra cost to the Council. These solutions will always be applied if feasible, and many of these have already been used to retain street trees in Sheffield. All of the options have limitations on the circumstances they can be used, for example, a footpath cannot be ramped that would cause water to drain into a household, we cannot leave a gap in a kerb that would cause a hazard to cyclists or encourages water to pool against a tree subsequently rotting its roots and some would only have a temporary effect.
If a tree is identified to be damaging the roads, pavements or third party property, then a number of engineering options are considered.
In addition to its legal duties under the Highways Act, the Council also has duties under the Equalities Act and is obligated to keep the pavements and roads safe and accessible for public use.
Myth 4: The Streets Ahead programme is just about replacing street trees
Truth: The Streets Ahead contract is a city wide highways maintenance contract between the Council and Amey to upgrade Sheffield’s roads, pavements, street lights, bridges and other items on and around our streets over a 25 year period.
Achievements to date include:
• Resurfaced over 1081 miles of pavement
• Replaced 2,770 drainage gullies
• Installed over 45,500 new LED streetlights
• Responded to 25,000 reports of flytipping
• Resurfaced over 500 miles of road
• Repaired over 52,200 potholes
Myth 5: Streets Ahead refuses to use flexible paving which would save most trees
Truth: Flexible paving can only be used where a tree is ‘Damaging’ roads and pavements and the damage is caused by a raised root track- meaning that the number of trees it can be used on is limited.
Context: Flexible paving is a porous pavement made from recycled rubber which increases the flexibility of the pavement material slightly. Flexible paving is one of the engineering options considered under the Streets Ahead contract. This option is limited by the height of the root track above the existing sub base in many instances and normal limits for this option are that the roots must not be above the desired finished footway surface.
This type of product is generally designed for use in tree pits and to improve usable footway widths allowing trees to be planted in narrow footways. Whilst flexible paving products are improving continuously, this option is short term as a tree will continue to grow and so the problem will always get worse over time.
Myth 6: The prices Amey quote to save trees, with engineering solutions, are too high
Truth: The rates used by Amey were part of their contract and were assessed prior to the contract being awarded. The rates have been compared to previous rates used by the Council before Streets Ahead, and other tenderers, and were found to be value for money for a contract of this size and scope.
Myth 7: All of the trees that form part of the Western Road war memorial site are the original trees that were planted in memory of those who gave their lives for this country
Truth: In reality, a number of these trees have already been replaced since the memorial was dedicated and we recognise it is the lasting memorial that is of primary importance in this case.
Commissioned age assessments of the trees in question on Western Road using both the “Mitchell’s Rule”
and Forestry Commission methodologies, confirmed that some of the trees actually post-dated the war quite significantly. An examination of the current tree arrangement indicates that there have been 26 trees removed in the past without replacement. A project group has been set up, working closely with the War Memorials Trust to review the proposals for Western Road as well as Frecheville, Crookesmoor, Meersbrook and Springvale Road where we believe there are other war memorial trees.
Myth 8: Street trees contribute significantly to the prevention of flooding
Truth: Street trees are generally situated in a pavement surrounded by water-resistant material meaning heavy rainfall is directed away from the tree into highway drainage.
Context: It is suggested that leaves capture quantities of rainwater delaying sudden water surface flows but that is at best likely to be very small quantities. A tree that is planted in a grass verge would soak up very little water in a flood but it is likely that the verge soil would make a much larger contribution than the tree. It is often the case that highway trees contribute to flooding through leaves blocking gullies and their roots blocking and collapsing drains and pipes.