Dr Terry Mabbett investigates a Forestry Commission pilot scheme testing different ways of slowing the spread of pests and diseases in ash, larch, spruce and sweet chestnut.
DEFRA and the Forestry Commission are gearing up with grants of up to £5,000 to deal with what they apparently see as looming worst-case scenarios for specific pests and diseases in English forestry. On 31 August they set out the pilot for a future full ‘tree health scheme’. The pilot is scheduled to run until 2024 with about 100 individuals or groups invited to submit an expression of interest.
Pest and disease foci of the pilot scheme include larch with the fungus-like pathogen Phytophthora ramorum (sudden larch death), and Chalara ash dieback caused by the true fungus Hymenoscyphus fraxineus. No surprises here, but other focal points, such as Cryphonectria parasitica (blight) or Phytophthora ramorum on sweet chestnut, and spruce infested with Ips typographus (eight-toothed European spruce bark beetle), may raise a few eyebrows and send shivers down the spines of more than a few foresters.
This is not because chestnut blight/ramorum on Castanea and Ips typographus on spruce are not present, but because their severity has generally been down-played by plant health authorities – certainly to a level that did not appear to require the availability of grants for felling affected trees and replanting sites with other trees, which is essentially what this tree health scheme will be offering. It will subsidise the felling of diseased and pest-infested trees and the re-planting of affected sites, as well as providing additional payments for post-planting management.
ABOUT THE PILOT SCHEME
The pilot will appraise various ways of slowing down the spread of specific insect pests and plant pathogens/diseases in specific commercial tree species while extending and expanding support to stakeholders already provided through the Countryside Stewardship Woodland Tree Health Grant.
The scheme will be delivered by the Forestry Commission, which will invite individual stakeholders and groups within targeted areas to participate in the pilot, running from August 2021 to 2024. It expects to award around 100 grant agreements.
The FC says it might invite potential applicants to take part because of a particular tree species, insect pest or plant pathogen/disease present on their land, although others can still put themselves forward if they think their situation meets the criteria. If the applicant is subsequently successful they will receive a grant to help pay for some of the work required to take out and replace the affected trees. The FC claims this pilot scheme will assist in developing a funding policy for future tree-health schemes.
WHO IS ELIGIBLE?
The FC says the pilot is aimed at those who qualify because they manage particular tree species and types of woodland in the following regions of England:
• North West, primarily targeting Arnside and Silverdale Area of Outstanding Natural Beauty (AONB) and the Lake District National Park
• South East and London, primarily targeting Kent and East Sussex
• West Midlands, primarily targeting the Malvern Hills AONB and Shropshire Hills AONB
However, others whose land is outside of these primary target areas but inside an eligible region may still be able to participate, especially if the FC believes the application will significantly contribute to the learning gained from the overall pilot scheme.
Eligibility requires that the trees or woodland managed must be in one of the following insect pest and pathogen/disease related categories:
• Common ash with Chalara ash dieback disease
• Larch with Phytophthora ramorum
• Spruce in the high-risk spruce bark beetle (Ips typographus) area
• Sweet chestnut with Phytophthora ramorum or sweet chestnut blight
The applicant must be either: landowner, occupier, tenant, landlord or licensor.
Applications can also be made by someone who manages trees on behalf of other people, e.g. an applicant from a local council or charity, or a land agent.
Stakeholders will be invited to take part in the pilot if they have been contacted by a Forestry Commission woodland officer (for example, having previously been given a Statutory Plant Health Notice (SPHN) which covers trees affected by one of the specified pests or diseases). However, persons not invited but who believe they are eligible might still be able to take part if they meet the requirements.
If someone is eligible and wishes to take part they will be required to fill in an expression of interest form containing brief information about their trees and land. The FC will subsequently carry out an initial assessment and a site visit. Based on this, an invitation to make a full application may be forthcoming. The FC says applications are scored competitively through a selection process which is based on maximising learning from the pilot.
Potential applicants should be aware that if a notifiable pest or disease is identified on their trees during an FC site visit, they may be issued with an SPHN and be legally required to deal appropriately with the pest or disease irrespective of whether funding is received as part of the pilot.
SITUATION IN RELATION TO OTHER FUNDING
Stakeholders in receipt of funding through other agri-environment or woodland schemes, such as the Countryside Woodland Tree Health Grant, and for the same activities as covered by the pilot scheme, are ineligible to take part. However, funding may be possible through the pilot scheme, even if the applicant is already in another scheme, providing they will not be paid twice for the same activities and work. Money received via the pilot scheme cannot be used to pay for work already carried before pilot scheme grant was accepted.
INDIVIDUAL AND GROUP GRANT APPLICATIONS
Stakeholders may apply as individuals or as a group depending on the situation. For example, applications for grants to cover larch trees with Phytophthora ramorum can be applied for as an individual or a group but grants covering common ash with Chalara ash dieback inside or outside of woodlands can only be secured by a group application.
Group applications must designate a specific person called a ‘facilitator’ who will have overall responsibility for making the application and carrying out the work. The facilitator is responsible for ensuring all concerned carry out the work which has been agreed to, and for providing the evidence of this work to the FC. Group grants will include an hourly fee to pay towards the facilitator’s organisational and coordination inputs within the group.
WHAT WOODLAND AND TREES ARE COVERED?
The pilot scheme covers trees both within and outside of woodlands, depending on which grant is applied for. For trees inside woodland, the group of trees for which a grant is applied must:
• cover at least 0.5 ha of land
• be at least 5 m high, or have the capacity to reach this height
• possess a crown cover which exceeds 20 per cent of the ground area
Trees outside of woodlands are defined as any trees or small woods covering less than 0.5 ha of land. These trees may include those in hedgerows, alongside a road or within parkland.
READ MORE: What is Phytophthora Pluvialis? Everything we know so far
Depending on the type of grant applied for, funding can go towards paying back some of the costs of:
• felling diseased trees, which means cutting down trees for removal, waste or wood chipping
• chemically killing diseased trees
• restocking and capital items to replace trees that have been felled because they have pests or diseases – restocking plans, for example the species and planting density used, must comply with UK Forestry Standard (UKFS) and any felling licence conditions
• infrastructure and access aids, for example to improve access to trees, so you can fell and remove them
• the maintenance of trees you have planted to replace trees you have felled; weeding costs are an example of this
• biosecurity items to stop pests and diseases being transferred, for example a pressure washer to clean vehicles and equipment
• facilitation fees for a person to manage your group’s application
• road closure costs and protected species site surveys, if you are applying for ash with Chalara ash dieback only.
WHAT ARE THE PEST AND DISEASE IMPLICATIONS?
Ramorum on larch and Chalara on ash: There should be no surprise about government support for dealing with Phytophthora ramorum on larch or Chalara ash dieback on common ash. Both diseases are essentially done-and-dusted deals for England in relation to frequency, severity and damaged caused.
Ramorum on larch: Phytophthora ramorum has rampaged through larch since 2009. There are no readily-available figures specific for England although the recorded decrease of larch across the UK tells a story. According to Forest Research figures there were 154,000 ha of larch across the United Kingdom before 2009. By 31 March 2016, the National Forestry Inventory was recording just 113,000 ha.
Chalara on ash: Estimates of ash affected by Chalara ash dieback since late summer/autumn 2012, when the disease was first recorded in the wider environment, are less than exact – understandably so given the ubiquitous and varied nature of ash, including standard trees, saplings, seedlings and coppice stools in woodland, hedgerow ash trees, hedgerow ash shrubbery and trees at all stages of development in the wider environment. The number of individual trees infected and possibly killed by Chalara since 2012 must now be approaching if not exceeding the number of mature elm trees (circa 25 million) dispatched by Dutch elm disease during the 1970s and 1980s.
Pre-Chalara there were an estimated 125 million ash trees in woodlands and between 27 and 60 million ash trees outside of woodlands across the UK, plus up to 2 billion saplings and seedlings in woodlands and non-woodland situations. Current calculations suggest up to 80 per cent of ash trees will eventually succumb to Chalara. By October 2012, 100,000 ash trees had already been destroyed in a vain attempt to stop the spread of Chalara. During the following year, plant nurseries destroyed hundreds of thousands of ash seedling and sapling trees following a ban on the movement of ash, which essentially put a stop to all new planting and re-stocking with ash.
BLIGHT/RAMORUM ON CASTANEA AND IPS TYPOGRAPHUS ON SPRUCE
Cryphonectria parasitica (chestnut blight) and Phytophthora ramorum on sweet chestnut, and Ips typographus on spruce is a completely different kettle of fish.
Blight on Castanea: Ever since blight was first identified in a sweet chestnut orchard in Warwickshire in 2011, plant health authorities appear to have played down the seriousness of the situation, despite Cryphonectria parasitica/blight being regarded as the worst disease of Castanea chestnuts worldwide. The Warwickshire orchard was planted in 2007 with material purchased from a nursery in France and around 50 per cent of the trees were found to be infected with chestnut blight in 2011. A subsequent trawl through the records of the French nursery and the UK distributor(s) by UK plant health authorities identified a further 10 outbreaks. However, UK destinations for a significant number of potentially infected consignments sourced from the same French nursery and sent to customers across the UK by mail order via UK distributor(s) between 2008 and 2011 could not be identified due to insufficient documentation. Continuing outbreaks are thought to originate directly and perhaps indirectly from these untraceable consignments of sweet chestnut planting material.
Forest Research says the disease has been found at a small number of sites since 2011. However, according to their own distribution map published in 2019, the disease had been recorded in 29 different 10 km grid squares in England since 2011. It is currently investigating 65 sites in England that have been identified with sweet chestnut blight disease. The disease is quite widely spread, with outbreaks recorded in Kent, East and West Sussex, London, Buckinghamshire, Berkshire, Devon, Cornwall, Dorset, Somerset, Cheshire, Nottinghamshire, Derbyshire and Norfolk.
UK plant health authorities have never committed to the original source of this disease which now looks set to cause long and lasting damage to sweet chestnut in England. The Forest Research website says: “It has not been possible to confirm how the pathogen entered the UK, including whether the infected plants discovered in 2011 were already infected when they were imported in 2007 [from France].” What do they want, a blight-cankered chestnut coppice pole to snap off, give them a clout and shout “Parlez-vous francais”?
The disease is clearly more widespread and serious than generally assumed. The pilot scheme’s focus on sweet chestnut in south-east England looks ominous. And there is perhaps tacit recognition that around 20,000 ha of sweet chestnut comprising coppice, coppice with standards and standards concentrated there and with most in Kent and East Sussex is at real risk from blight.
Ramorum on Castanea: The regional distribution and epidemiological threat of ramorum to sweet chestnut is entirely different. Virtually all outbreaks confirmed so far are in western England and what you would expect from a fungus-like pathogen heavily reliant on free water and humidity for all aspects of its life cycle.
Despite sweet chestnut’s status as a sporulation host for P. ramorum, early observations showed only trees exposed to heavy inoculum pressures from other more powerful sporulation hosts such as Rhododendron ponticum were becoming infected. But all that changed in 2015 when a cluster of new outbreaks was found in western England, mainly in Cornwall and Devon but as far east as the Somerset/Wiltshire border. This time round, infected trees were isolated from the immediate presence of other sporulation hosts, suggesting long-distance travel of P. ramorum spores and perhaps transmission between neighbouring sweet chestnut trees.
Most recent figures released by Forest Research show 68 sites confirmed with P. ramorum between 2015 and 2020 (1 February 2020). Statutory plant health notices were issued, with 132 ha of sweet chestnut treated. When considered in combination with ongoing levels of blight, current levels of ramorum on sweet chestnut are clearly of concern for the future sustainability of this crucially important tree.
Ips typographus on spruce: Following the very first pair of confirmed outbreaks of Ips typographus on Norway spruce in the Ashford area of Kent in late 2018, the FC imposed restrictions on the movement of specified material of the genus Picea (spruce) within a demarcated area covering virtually the entire land area of Kent and a small adjoining area of East Sussex.
The demarcated area was extended in July 2021 to cover virtually the whole of East Sussex, small areas of East Surrey, West Sussex and north-east London; and significantly roughly half of Essex from the Thames Estuary up the coast as far north as Clacton and Colchester. This had followed three further outbreaks confirmed by the FC in 2021; two in Kent and one in East Sussex.
Norway spruce is not found in quantity within this latest demarcated area, but much more so further west into the Surrey Hills and deeper into West Sussex, so perhaps these areas should be regarded as ‘high risk’ even though they are not currently within the demarcated area – and especially since a potential outbreak was previously flagged up by a forestry contractor working in the Surrey Hills but who was apparently unwilling to reveal the location.
In yet another sign that all is not well in relation to ongoing problems with Ips typographus, the Forestry Commission has simplified felling licence applications as of 22 October 2021. The reason given is to prevent the spread of pests and diseases and to protect public safety.
The Forestry Commission says the change applies to very specific situations such as preventing the spread of quarantine pests and diseases, and it gives Ips typographus as an example of such a pest.
Invasion by such pests and diseases essentially occurs in three stages:
1. The quarantine pest or disease enters the country on planting material, logs, timber or other plant material, having slipped through biosecurity inspection procedures at the port
2. The pest or disease proceeds to establish a foothold in the United Kingdom
3. The pest or disease starts to spread out from the site(s) where it first established
Ips typographus is apparently at stage three, presumably the reason why felling licence procedures have been simplified, so that sites found to be infested with Ips typographus can be dealt with immediately. Contractors and others working on the ground with the very first outbreak of Ips typographus in the Ashford area of Kent in late 2018 say on-site evidence suggested the bark beetle pest had been established there for between two and three years.
This new focus on Ips typographus by the FC rings danger bells for UK forestry as a whole and gives credence to on-the-ground reports that Ips typographus is already more widely spread than indicated by the five outbreaks so far confirmed by the UK plant health authorities. If this pest reaches northern England, Wales and Scotland, and subsequently develops a taste for Sitka spruce, then the UK and devolved Welsh and Scottish governments will need to plant a whole lot more forest and woodland than the planned-for 30,000 ha per annum. It won’t be a case of ‘net zero’ but ‘ground zero’ for UK forestry.
AUTHOR’S NOTE
Details of the grant payment rates for:
• ash with [Chalara] ash dieback disease
• larch with Phytophthora ramorum
• spruce with or at risk from spruce bark beetle
[Ips typographus]
• sweet chestnut with Phytophthora ramorum or
chestnut blight [Cryphonectria parasitica]
are set out at www.gov.uk/guidance/tree-health-pilot-scheme.
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