Impact of Tree Diseases

Date of Meeting:

24th November 2020

Report of:

Executive Director Economy Environment and Culture

Contact Officer:


Robert Walker


01273 294349



Ward(s) affected:








1.1         The council has committed to becoming carbon neutral by 2030. A significant contributor to this needs to be increasing the number of trees in the city and the council has an ambition to double the city’s tree cover by 2045 in accordance with the Friends of the Earth campaign for this goal to be achieved nationally.  Trees provide well established benefits beyond their importance in reaching net zero greenhouse gas emissions with eco-services such as reducing airborne pollutants, decreasing urban temperatures, improving mental health and reducing flood risk amongst many others.


1.2         The council’s Open Spaces Strategy 2017 and draft Tree Strategy have also set out the importance of trees and the need to invest in them and specifically identified the need to continue to invest in protecting the city’s elms. The draft Tree Strategy also identifies the need to future proof our tree stock to make it more resilient to the challenges we face both in terms of climate change and current and future diseases.


1.3       Unfortunately the city’s trees are being impacted by two very serious diseases. Ash dieback cannot be contained and the report updates the committee and sets out a recommended approach to dealing with this and the costs that will need to be budgeted for by the council going forward.


1.4      Elm disease can potentially be brought back under control and the report updates the committee on options for the city’s elms and the associated costs of dealing with this.


1.5      This report sets out the costs and outlines the recommended approach for the council including Housing owned land but excluding ash dieback on land managed by schools. The City Parks arboricultural team will coordinate the work to tackle these diseases.





2.         RECOMMENDATIONS:    


That the Environment, Transport & Sustainability Committee:


2.1         Note the initial projected cost of £3.4 million to deal with ash dieback (of which £0.352 million relates to ash trees on housing land) over the next 5 – 10 years.


2.2         Recommend to Policy & Resources Committee the allocation of an initial tranche of £0.400 million funding during the 21/22 budget setting to start tackling Ash die-back.


2.3         Notes the cost pressure of £0.300 million in 20/21 for dealing with elm disease which is being managed within budget by making in- year savings.


2.4         Recommends that Policy & Resources allocate £0.200 million in the budget setting for 21/22 to deal with elm disease next year.


2.5         Approves the approaches being taken to tackle these two diseases.




Elm Disease


3.1         In nearly all other parts of the country elm disease [ formally known as Dutch elm disease] killed the majority of elm trees in the late 1960s and 1970s. In Brighton and Hove the disease has been held at bay by sanitation felling [ the prompt removal and destruction of infected trees] which has been successful because of the geography of the City and the assistance of neighbouring authorities.


3.2         Elm disease is a fungal disease carried by beetles which lay their eggs in the bark of elm trees; it can also be transmitted by root- joining between elm trees. The beetles are not strong flyers and generally do not travel more than 3 to 4km under their own steam but can travel greater distances with the assistance of the wind. To contain the disease infected trees need to be quickly identified and destroyed. Elm beetles are transported in some wood products, notably fire- wood. Any elm logs [with bark still attached] are potential habitat for the disease carrying beetles


3.3         This year we are losing far greater numbers of elms than normal. If we do not bring the disease back under control elm loss will rise rapidly and lead to the loss of most of the city’s elms. Elm losses of recent years are shown in Appendix 1:  each case will be at least one tree but will often be a group of trees.


3.4         The city’s current elm stock is of national importance and we are privileged to hold the National Elm Collection. There are very few areas in the world that still have the variety and number of elms that we have in Brighton and Hove.


3.5         The reason for the current outbreak is thought to be a combination of factors and similar problems are occurring in Eastbourne which had also managed to preserve a good elm population. The reasons are thought to be as below:

·         Failure to gain access to land with infected trees not owned by the council in previous years

·         Ideal breeding and flying conditions for the beetles [a lot of warm windy days]

·         Elm logs being brought into the city

·         Neighbouring authorities no longer able to support us by controlling the disease beyond the city’s borders

·         Failure to contain an outbreak in Woodvale last year


3.6         In previous years we have been able to pinpoint the source of infections with a good degree of accuracy. The picture emerging at the moment is that following on from a significant amount of elm loss along the A23 corridor last year, thought to originate from infected trees on land that we cannot access, this source has continued to generate disease carrying beetles this year coupled with the fact that we failed to fully deal with all the new infection sites  last year. In addition to this the ideal flying conditions for the beetles has meant infections within the city have spread more rapidly and infections coming in from neighbouring authorities’ areas have increased.  


3.7         The council’s approach to dealing with Elm diseased trees is to remove and destroy infected elm trees on public and private land. To help do this we:

·         Use additional council staff outside our arboricultural section to spot indicators of the diseases

·         Continually take opportunities to publicise the Council’s work to protect the elms and encourage the public to help

·         Aim to ensure that all landowners in the city are aware of the problem and remain vigilant

·         Remove all elm trees showing signs of disease as rapidly as possible

·         Dispose of diseased elm trees by burning or shredding. If tightly controlled elm timber can be used, however, it needs prompt and thorough bark removal or to be taken a significant distance from Brighton and Hove.

·         Try to prevent the selling of elm logs in the city through road signage, raised public awareness of the Elm Disease Control Zone, the area where we are still trying to prevent spread of the disease,  and appeals to log merchants



3.8         It is critical to act swiftly in removing diseased trees in order to halt the spread of the disease but also to minimise the financial risk that is generated by every additional elm tree that becomes infected which can support tens of thousands of beetles over the summer period.


3.9         The additional cost of next year’s control work has been based on this year’s cost. We are expecting an improvement next year as a result of this year’s major campaign of felling and removal. However, although we have carried out a lot of work on the A23 corridor across the city we do not think the source of infection has been entirely removed and, therefore, we are anticipating another bad year next year, although this is difficult to predict accurately.


Ash Dieback Disease


3.10      The situation is very different with ash dieback as this disease cannot be contained. The disease is transmitted as fungal spores from infected leaves a carried by the wind. As such there is no viable way to stop the disease given the scale of the disease across the UK and the rest of Europe. In common with the rest of Europe the majority of our ash trees will die [ probably around 70%]. Although not one of the commonly planted trees in the city’s parks or streets it makes up a large percentage of our woodland and is estimated to be around 25%. This woodland is principally on the outskirts of the city but does cover some central areas such as Woodvale.


3.11      The council will be faced with large numbers of dead trees to deal with. In some privately owned woodlands where there is no permitted public access ash trees are being left to collapse naturally and then removed. Although there may be some areas that the trees can be left to collapse naturally in the city the options for doing this are very limited given that council owned land and woodlands are mostly accessible to the public for recreation. Most council owned diseased ash trees will need to be made safe in order to avoid the risk of injury or damage to property.


3.12      Officers have looked at the approach being taken by neighbouring local authorities, in particular the approach being taken by Adur and Worthing Councils and Eastbourne BC. These authorities have begun works on their woodland areas on the fringes of their built-up areas. Similar to Brighton and Hove, ash trees in advanced states of decline are concentrated within woodland areas on the edges of the authorities’ areas. The impacts of Ash Dieback are slow to materialise in more urban areas including street trees and parks, thought to be due to the more sanitised conditions with less leaf litter [a source of the fungal spores that spread the disease]


3.13      These Local Authorities have employed dedicated Ash Dieback officers who have focused initially on woodland areas by conducting detailed surveys in order to programme felling works on a priority basis, opened dialogue with relevant stakeholders including the Forestry Commission, SDNP and The Tree Council, accessed grants and felling licences required and also sought funding for replanting proposals. Some tree clearance works have been completed on priority woodland areas with further works programmed following the production of detailed woodland management plans. The local authorities have less woodland than BHCC to contend with but began ash dieback planning (based on the Tree Council’s Ash Die Back Toolkit) approximately two years ago.


3.14      A key aspect to the authorities planning in relation to Ash dieback has been the communication of the situation and proposed works to the public and stakeholders in preparation of high levels of tree loss and the impacts of this.


3.15      Diseased ash trees adjacent to the highway and/or in high footfall areas with be prioritised for felling in order to minimise the risk to public safety. The Forestry Commission and Tree Council accept that where public access (e.g. roadside trees or those by paths) is a factor an appropriate risk-based approach is required considering tree condition and the threat to safety with tree clearance potentially required. However the Forestry Commission is following a policy of retaining any ash trees which display resistance to the disease via consultations on felling licence permits.


3.16      As our arboricultural staff have been occupied with elm disease our ranger team are carrying out further survey work to help increase the accuracy of cost estimates for dealing with ash dieback and identify areas of imminent danger. This will have some impact on their usual work. Data has been gathered by the Ranger team on areas of woodland or dense tree cover around the fringes of the city to identify where ash trees are located and record the condition of these with respect to the symptoms of ash dieback (i.e. loss of leaves, large amounts of deadwood) as a starting point for managing the disease in these areas.


3.17      Survey work already done has highlighted two areas, Coldean Lane and Mill Road, where tree felling will be required this winter. This will be high profile and before budget is approved. This work is currently being costed and it is anticipated will be dealt with by in- year savings elsewhere within the Environment directorate.


3.18      As next steps, a specialist consultant will be engaged to assist with planning and prioritising work ensuring that trees in higher risk areas are removed first. This will be funded from existing budgets. An Ash Dieback co-ordinator post is being created in order to ensure that the work is planned and prioritised according to risk and that the appropriate statutory assessments are completed prior to felling.


3.19      Failure to adequately manage the risks of diseased trees falling could leave the council liable to prosecution, investigation by the Health and Safety Executive and substantial financial claims being brought against the council, should a tree fall and injure someone or someone’s property or should there be a near miss.


3.20      The current estimate of removing diseased Ash dieback is £3.4m over 5-10 years but the substantive part of this cost is likely to fall within the first 5 years. Some of this cost has been calculated using number and location of ash trees where this is known but most has been by estimating where numbers of trees are not known. For some areas we are able to be more accurate, for example on Highways Land where the numbers of Ash trees are known and logged. In other areas, such as woodland areas, the cost estimation is based on an estimation of the number of ash trees and therefore the estimated costs have a higher risk of inaccuracy. An external consultant has been engaged to review our proposed approach with particular reference to checking the costings.


3.21      All wood felled will be sold and the income used to offset the cost and this has been factored in to the £3.4m estimated cost.


3.22      The cost of felling and replacing trees on Housing owned land would be funded by the Housing Revenue Account.


The Future of Tree Planting in the City


3.23      With the combination of further possible tree disease and climate change on the horizon it is important to build a more resilient tree stock going forwards and traditional dependence on a limited range of trees has put us in the vulnerable position we are now in. With tree planting we are typically planting trees with a useful life of over 100 years over which time new diseases may come along and full effects of climate change upon our trees is difficult to predict. This is why it is so important to have a variety of trees capable of adapting to or tolerating the expected rise in temperature and extreme weather events.


3.24      Although there is little prospect of external-financial help removing our dead and dying trees we are likely to get help with new and replacement tree planting both in terms of government grants for woodland replanting and benefactors helping with tree planting in general. The budget estimates are based on removal costs only.


3.25      The restocking and recovery of our woodland presents an opportunity for greater public involvement in woodland management and the opportunity to do something to help in the fight against climate change. We have already seen small scale woodland management by specific groups and volunteers working with our rangers and it is planned to expand this further. There is also a lot of interest from individuals and groups around the city who want to plant trees and hopefully this can be harnessed to get our woodlands replanted and give the public a satisfying and educational experience.


3.26      The Council has legal responsibility for all of the trees on the land it controls, although some leases will pass responsibility onto tenants. Unlike elm disease we are not proposing to deal with ash dieback on private land. We are however responsible for enforcing action on landowners with trees that endanger the highway. The biggest risk from ash dieback and elm disease [ if we lose control] will be from branches from or the whole infected tree falling and causing damage to people or property. With the exception of elm disease [ whilst we still have it under control] and our highway enforcement responsibilities this report does not cover trees on private land.




4.1         The costs for failure to control elm disease is very high and are difficult to be precise on but to illustrate costs we do have accurate figures for numbers of elm street trees. To fell and replant all of the elm trees [ in practice some would survive] will be in the region of £10 million. On top of the cost to the council will be the cost to residents and other landowners and the drastic loss of trees throughout the city, especially on streets.


4.2         Going forward assuming we bring the elm disease infection back under control the options will either be to continue as we have been from the outset of elm disease planting elm widely across the city or we start to erode elm numbers and reduce our vulnerability should we lose control at some time in the future. The best way of reducing our dependency on elm whilst still maintaining a good elm population was previously thought to be to introduce a barrier area in the outer wards of the city particularly to the south-west where we would no longer plant elm. This was because typically our infections have come in from outside the area and the prevailing wind brings the beetles in from the south- west. The current outbreak is not following this pattern as the source of infection is thought to be established in the centre of the city. A general policy of not planting elm could be introduced now but if we are going to introduce a more measured reduction in our elm dependency this is better left until this year’s infection is brought under control.


4.3         Ash dieback cannot be contained and will lead to large numbers of dead trees. These trees will be a hazard in any public place but also would be useful habitat for biodiversity if left standing where the risk from the falling tree is very low. The only options that the council will have is how much risk to take when leaving dead wood or other impacted trees standing. The safety issue is complicated by the fact that if we start felling infected ash in an area this will open the area up and make the remaining trees unstable so if we are working in high risk wooded areas, for example along roads such as Mill Road and Coldean Lane areas of woodland ,we will have to remove a substantial amount of trees near the roads. Neighbouring landowners are clea -felling along roads bordered by woodland with significant ash in it, for example the National Trust at Ditchling Beacon.


4.4         As the response to Ash Dieback is unfolding as this report is being written the information available from other authorities is about plans rather than completed programmes. Other authorities have identified high risk areas as their priority and started on these whilst carrying out more comprehensive surveys of their whole tree stock. There are some variations in the approaches being proposed, for example the New Forest are proposing more selective felling but with repeated visits a more costly but arguably better approach environmentally. Other authorities are also identifying the potential opportunity to replant with a more resilient species mix going forward. This report does not cover replanting but if we are able to secure funding we should also look to do this.




5.1         We have been providing information to the public in relation to elm disease and engaging the public in trying to contain it where some dedicated volunteers have been identifying suspected elm disease and feeding this through to the council and the general public have been encouraged to report sightings.


5.2         There has been little public engagement on Ash dieback but information will need to go out to areas where felling will have a high impact as the response to Ash dieback progresses. As per paragraph 3.25 the focus on the inevitable changes to our woodlands does create an opportunity for greater public education and engagement in the future of our woodlands.


5.3         In the Councils Open Spaces Strategy 2017 consultation the public clearly identified trees as the most important thing to them in the city’s parks and open spaces: the survey had 3542 responses. There has been a lot of public enthusiasm to increase the number of trees in the city so there can be little doubt that the public will want us to do what we can to protect the city’s trees.


5.4         Both of these diseases are covered in the draft tree strategy. Consultation on this was put on hold initially due to the impact of COVID 19. However as the scale of disease impact on our City becomes both clearer to officers and obvious to the public the draft strategy will require updating to reflect the approach being taken to both of these diseases before going to public consultation.


6.            CONCLUSION


6.1         The Council should continue to fight to preserve the city’s elm trees both for financial reasons and to conserve a unique collection of trees and the wildlife that depends upon them. When the outcome of the recent serious elm disease outbreak is clear the council should reconsider the approach to managing elms  with particular emphasis on what can be done to reduce our vulnerability to elm disease going forwards.


6.2         It is recommended that funding is allocated to deal with the dead trees which are already appearing across the city as a result of ash dieback by felling these and in some instances nearby trees to reduce the risk of injury and damage to property as these trees fail. There will be small numbers of trees that pose very little risk and can be left to collapse naturally




Financial Implications:


7.1         Given that the council does not have the option to ‘do nothing’, the proposed measures outlined in the report reflect the appropriate level of action that the council needs to take in order to prevent health and safety issues and minimise the costs incurred to manage the current stock of Ash and Elm trees.


7.2         Should the committee accept that these costs are unavoidable and support the recommendation to allocate £0.600 million to support the management of Ash die-back (£0.400 million) and Elm disease (£0.200 million), then the commitment will need to be referred to Policy & Resources Committee for inclusion in the 2021/22 budget setting process.


7.3         The initial projected cost of £3.4 million, and any associated borrowing costs, to deal with Ash die-back (of which £0.352 million relates to ash trees on housing land) over the next 5 – 10 years will need to be noted as an on-going budgetary pressure in any medium-term financial plan.


            Finance Officer Consulted: Jill Fisher                                           Date: 29/10/20


Legal Implications:


7.4      In addition to its common law and statutory duties of care as landowner, the Council has powers to act in respect of dangerous trees. Under the Local Government (Miscellaneous Provisions) Act 1976 the Council has power to remove dangerous trees on private land either in response to a request or where such trees are a danger to land occupied by the Council. The power allows the Council to recover its reasonable expenses in taking action. Moreover, under the Highways Act 1980 the Council, as highway authority, has a power to require the cutting back or felling of trees that overhang or are a danger to roads and footpaths.


Legal Officer Consulted: Hilary Woodward                                  Date 28/10/20          



Equalities Implications:


7.5      None


            Sustainability Implications:


7.6         There are both direct and indirect sustainability implications to these disease in that we will lose trees and the animals and plants that depend on them. This will set back our plans to use trees to offset carbon use and the other benefits trees provide such as air quality. It is anticipated that there will be ash that survives ash die back in Brighton and Hove as well as the rest of the country. Should we lose certain elm species other dependant wildlife such as the white hair streak butterfly will also suffer. The council has committed to becoming carbon neutral by 2030. A significant contributor to this needs to be increasing the number of trees in the city and the council has an ambition to double the city’s tree cover by 2045 in accordance with the Friends of the Earth campaign for this goal to be achieved nationally.


Brexit Implications:


7.7         None


            Risk and Opportunity Management Implications:


7.8       A combination of global warming and the spread of pest and diseases across the city has made it clear that an overdependence on a limited number of tree species is a high risk approach as identified in our draft tree strategy. The loss of so many ash trees and the potential loss of elms will provide planting opportunities which can be used to build a more resilient tree stock going forwards







1.        Record of elm disease infections dealt with by the council.    


Background Documents


1.         None