Tree health is regulated under plant health legislation. This is required and implemented to promote safe trade and protect the environment.

The Plant Health (Official Controls and Miscellaneous Provisions) (Scotland) Regulations 2019

Scottish Forestry, on behalf of the Scottish Ministers, undertake various tree health regulatory actions such as inspections and issue of Statutory Plant Health Notices under powers contained within the Plant Health (Official Controls and Miscellaneous Provisions) (Scotland) Regulations 2019. 

The Plant Health (Official Controls and Miscellaneous Provisions) (Scotland) Regulations 2019 (legislation.gov.uk)

These Scottish Regulations supplement other plant health legislation which applies in Scotland, as described below.

The ‘PHR’ sets out rules for a risk-based approach to identifying and managing plant health threats. 

This includes:

• controls and restrictions on the introduction into, and movement within, GB of plants and plant products
• the management of outbreaks of harmful plant pests and diseases

It lists systems and requirements authorities must put in place including:

• maintaining and updating lists of controlled plant pests
• conducting regular, systematic surveys to detect these pests following standardised methods
• developing emergency plans for serious outbreaks
• facilitating a plant passport system so plants can be traced back to their original source 

It also states the obligations of professional operators and other persons.

Plant Health Regulation 2016/2031 (legislation.gov.uk)

The plant health sections of the ‘OCR’ provide the enforcement mechanism for the PHR. 

The OCR sets out how authorities must inspect, monitor compliance and enforce the PHR rules. 

Checks are conducted across the supply chain including premises where regulated plants or plant products are grown, stored, transported, processed or sold.

Official Controls Regulation 2017/625 (legislation.gov.uk)

Importing plants, plant products or seeds? 

You can find the latest rules using the ‘Plant health information and import rules service’.

Check plant health information and import rules (UK Government website)

The ‘PCR’ establishes uniform measures to implement the PHR, laying out lists of regulated pests, commodities and associated plant health import and internal movement requirements.

Measures taken to prevent introductions and control the spread of plant pests and diseases differ according to the risk category the pest or disease is assigned to.

The Phytosanitary Conditions Regulation 2019/2072 (legislation.gov.uk)

Key differences between categories of plant pests and diseases listed in PCR Annexes relate to:

• their presence in GB
• the purpose of classification
• where authorities focus action to address the threat posed 

Pest categories

A subset of the GB quarantine pests in the PCR are categorised as GB priority pests.

Priority pests are listed under this legislation. These are pests for which their potential economic, environmental or social impact is the most severe in respect of Great Britain.

The Commission Delegated Regulation (EU) 2019/1702 (legislation.gov.uk)

See our table below with the subset of priority pests that affect trees. Use the direct links to the UK Plant Health Risk Register for detailed pest risk assessment information.
 

This Act is the primary legislation governing plant health in Great Britain. It defines competent authorities for the purposes of the Act and grants them powers to make secondary legislation to:

• prevent the introduction and spread of tree pests and diseases
• create plant health offences
• charge fees for some operations

Plant Health Act 1967 (legislation.gov.uk)

A Statutory Plant Health Notice (SPHN) is a legal Notice requiring you to take certain steps to treat, destroy or dispose of a controlled plant pest or prohibited material, or take other actions to prevent the establishment or spread of a controlled plant pest.

SPHNs are issued in Scotland:

• by plant health authorities including Scottish Forestry under the Plant Health (Official Controls and Miscellaneous Provisions) (Scotland) Regulations 2019

  The Plant Health (Official Controls and Miscellaneous Provisions) (Scotland) Regulations 2019 (legislation.gov.uk)

• to landowners or managers when controlled plant pests or prohibited material are found

Your SPHN will state what you must to do, where, and within what time frame.

Measures required in tree health SPHNs may include:

• removing tree species within a certain distance of infected or symptomatic trees
• chipping or debarking felled trees on site
• carrying out extra biosecurity measures
• notifying your local Conservancy when measures are complete 

Pine-tree lappet moth (PtLM) is subject to statutory controls to prevent the introduction of new populations. Our tree health team conduct monitoring and review restrictions in partnership with industry, research, and environmental bodies.

Is pine-tree lappet moth found in Scotland?

Pine-tree lappet moth (Dendrolimus pini) is only known to occur in Scotland in the Beauly catchment area near Inverness. 

A male moth was first detected here in 2004 and a breeding population was later found in 2008. Numbers in and around the core breeding area have remained low.

No breeding populations have been detected elsewhere in the UK. 

The preferred host for pine-tree lappet moth (PtLM) is Scots pine (Pinus sylvestris). But it will feed on other species of pine and conifers more generally. 

Moth outbreaks occur periodically across much of Europe and Russia. This causes substantial damage to pine forests. 

Pest Risk Analysis for PtLM available from the Forest Research website.

Pest Risk Analysis for Pine-tree lappet moth (Forest Research website)

How does pine-tree lappet moth affect trees?

The caterpillars can strip needles from entire canopies, leaving them bare. 

In severe cases, this kills the tree. This defoliation can weaken the tree, making it more vulnerable to attack by other pests or diseases.

Female moths are less mobile than male moths that can fly significant distances (kilometres). Longer distance spread also occurs through the movement of cocoons and larvae on wood and foliage.  

PtLM is subject to statutory action against interceptions to prevent further introductions. 

A containment strategy is in place for populations in the Core Breeding Area in Scotland.

Restrictions apply in this Area between 18th May and 31st August, to:

• the movement of pine timber
• all coniferous timber grown in a pine mixture (intimate or group)

These restrictions came into force on 1st April 2021. They replace wider restrictions introduced in 2010 on movements of timber and branch wood from the breeding area. 

No restrictions apply to pine timber:

• harvesting or extraction to roadside in the PtLM Core Breeding Area
• outside the Core Breeding Area

Pine-tree lappet moth Core Breeding Area in Scotland (as of 31st December 2019)

Our annual programme of PtLM population monitoring is carried out on behalf of the Pine-tree Lappet Moth Management Group. 

• PtLM population densities have remained low since monitoring began in 2008
• population size is monitored annually to assess risk

Group membership includes:

• Forest Research
• Butterfly Conservation
• NatureScot
• the Confederation of Forest Industries (Confor)
• forest managers

Phytophthora pluvialis is a fungus-like pathogen that causes dieback of coniferous trees including western hemlock and Douglas fir.

Is Phytophthora pluvialis found in Scotland?

The pathogen Phytophthora pluvialis is a fungal-like water mould found in Scotland, infecting western hemlock (Tsuga heterophylla) and Douglas fir (Pseudotsuga menziesii).

How does Phytophthora pluvialis affect trees?

Symptoms of P. pluvialis infection include:

• needle cast
• shoot dieback
• lesions on the stem, branches and roots

More information about symptoms can be found in the Forest Research guide.

Phytophthora pluvialis: Symptoms on western hemlock and Douglas-fir (Forest Research website)

When was Phytophthora pluvialis discovered?

The pathogen was first described in 2013 from Oregon, USA, infecting tanoak (Notholithocarpus densiflorus). 

One year later it was discovered to be the causal agent of ‘red needle cast' in radiata pine (Pinus radiata) in New Zealand. 

Phytophthora pluvialis was discovered in Scotland in 2021 after extensive surveillance following the first UK detection in Cornwall.

First report of Phytophthora pluvialis in Europe causing resinous cankers on western hemlock (British Society for Plant Pathology website)

Report suspected sightings of Phytophthora pluvialis

Report suspicious symptoms on any tree in Scotland to TreeAlert using the general enquiry webform.

Use TreeAlert (Forest Research website)

The web form asks for:

• your contact details
• the location of the sighting
• clear photographs of the affected tree(s) in context and the symptoms

For more information on what to include in your report, visit the ‘TreeAlert - what to do page’.

What do you need to make your report (Forest Research website)

Once you submit your report, diagnosticians at Forest Research will review it. They may contact you to request additional details.

Any suspected findings of regulated pests or pathogens will be sent to our Tree Health Officers for follow-up.

As of 4th March 2024, all demarcated areas for Phytophthora pluvialis in Scotland are removed.

The Plant Health (Phytophthora pluvialis) (Scotland Demarcated Areas Revocation) Notice revokes previous demarcated area notices.

Tree pests and pathogens are a major threat to our forests. Tree professionals, landowners and managers have an important role to play in preventing pest and disease introductions and spread.

A combination of preventative measures can:

• reduce risks from both current and future outbreaks
• enhance resilience and biosecurity

These measures are more effective economically, environmentally and socially than controlling outbreaks. 

Tree pests and diseases follow a predictable pattern called the pest and disease cycle. 

The further through the cycle the pest or disease progresses, the worse the outbreak, and the harder it is to eradicate, contain, or mitigate the impact. 

Where do you interact with the cycle? 

Transport

The cycle starts with the transport of a pest or disease over long distances to a new location. 

This can occur naturally, for example on wind currents, but is often aided by people trading and moving plants and soil. 

Pests and diseases often have special survival strategies that keep them alive during these phases with hostile conditions.

Transport leads to introduction, and can restart the cycle during the establishment and spread steps. 

Introduction and establishment

At the end of the journey, the pest or disease is introduced to a new area. 

Introductions to unsuitable areas may fail to establish. Repeated or larger introductions make establishment more likely. 

And if the host, habitat, and climate conditions are suitable, the pest or disease can build up larger populations.

Spread

Once established, pests or diseases start to spread, locally at first. 

Spread is helped by wind, rain, livestock, wildlife, people, trade, vehicles and/or equipment. 

The speed and intensity of spread depends in part on:

• the characteristics of the pest or disease
• how many hosts it can infect
• how widespread and how susceptible they are

The biggest economic, environmental, and societal impacts will be observed at this stage.

Preventative measures carried out to disrupt the dispersal of harmful organisms including tree pests and diseases are called ‘biosecurity measures’. 

Wherever you interact with it, take action to break the pest and disease cycle. 

Prevent transport

• follow guidelines and regulations on importing and moving plant products
• ensure vehicles and machinery arrive clean and leave clean
• find out if plants for planting or timber movement or transport restrictions apply in your area

Prevent introduction and establishment

• plant tree species suited to your site conditions and explore options to improve forest resilience

  Examples of forest resilience 

• manage invasive understorey plants

  • besides outcompeting native ground flora and preventing natural regeneration of trees, invasive plants - for example Rhododendron ponticum - could also be hosts for serious diseases that could be spread to nearby trees. 

    Invasive rhododendron

• source seed and planting stock responsibly;
  • follow guidelines and regulations on importing and moving plant products
  • use suppliers with high biosecurity standards
• make sure that footwear and all equipment including tools, ropes, and clothing are free from soil and organic material before entering and leaving a site
• nominate a responsible person for biosecurity to:
  • design biosecurity protocols and training
  • install new infrastructure
  • monitor and improve delivery of biosecurity best practice to prevent spread to, within, and from your site

Prevent spread

• raise public awareness of 'Keep it Clean' responsibilities

  Visiting woods and forests

• when transporting timber, risks should be considered
• adhere to Statutory Plant Health Notice (SPHN) requirements within required timelines
• ensure SPHN biosecurity requirements are followed by everyone accessing the site
• comply with movement restrictions, inspection requirements, and the transport of material to Authorised Processors

Report symptoms

• monitor your trees regularly for signs of pests or diseases; symptom guides are available from Forest Research

  Pest and disease resources (Forest Research website)

  Pests and diseases by tree species (Observatree website)

• report suspected pest and disease symptoms to TreeAlert

  How to submit a report TreeAlert (Forest Research website)

  TreeAlert Demystified: What happens when you submit a report? (Observatree website)

Making a biosecurity action plan will help you identify where and how you can break the disease cycle. 

Familiarise yourself with pests and diseases that may affect your trees, now and in the future using:

• our tree health pages

  How tree health is protected in Scotland

• information on the UK plant health portal

  UK plant health information portal

• the UK Plant Health Risk Register

  UK Plant Health Risk Register

• find and use management guidance

  • check our tree health pages e.g. toolkits for managing ash dieback

    Ash dieback 

  • guidelines and research published by Scotland’s Plant Health Centre

    Publications - Plant Health Centre (Plant Health Centre website) 

  • management strategies published on the UK Plant Health Information Portal

    Management strategies - UK Plant Health Information portal (Department for Environment, Food and Rural Affairs website)

There are lots of resources to help you make a plan:

• your biosecurity action plan

  Biosecurity (Forest Research website)

• top 10 best practice tips for anyone who moved plants in the UK

  Biosecurity best practice: Top 10 tips - UK Plant Health Information portal (Department for Environment, Food and Rural Affairs website)

• biosecurity best practice for conservation and nursery production of plants

  Biosecurity best practice for conservation (Plant Health Centre website document) 

• how biosecurity can prevent the introduction and spread of tree pests and diseases

  How biosecurity can prevent the introduction and spread of tree pests and diseases (UK Government website)

• biosecurity practices to support plant health

  Biosecurity practices to support plant health: a review of knowledge and practice (Plant Health Centre website document)  

• guide to implementation of phytosanitary standards in forestry

  Guide to implementation of phytosanitary standards in forestry (Food and Agriculture Organisation of the United Nations website document)

Regulations are in place to prevent spread of Phytophthora ramorum in Scotland to protect larch. Our tree health team conduct national scale aerial surveillance to monitor larch trees for new symptoms every year. 

Is ramorum disease found in Scotland?

Ramorum disease is caused by a pathogenic fungal-like water mould called Phytophthora ramorum. 

It was first found in Scottish plant nurseries in 2002 and in gardens and parks in 2007. The first infection on Scottish larch trees was confirmed in 2010. 

• UK Plant Health Risk Register entry for Phytophthora ramorum with links to the Pest Risk Analysis conducted in 2009.

  Phytophthora ramorum and kernoviae (DEFRA plant health portal website)

• Our map shows where control measures are in place to remove larch with ramorum disease. 

  Phytophthora ramorum Outbreak Map - updated October 2024

• You can also view this information on our map viewer.

  Phytophthora ramorum Outbreak Map - Scottish Forestry Map Viewer

• And you can also download the Statutory Plant Health Notice dataset from our open data portal.

  Statutory Plant Health Notice dataset - Scottish Forestry Open Data portal 

  We update the dataset monthly, and you can filter it for the pest or disease of interest using the ‘Pest or Disease’ column.

The signs and symptoms of ramorum disease vary with host species. 

The Observatree field guide to identifying Phytophthora ramorum describes symptoms on several different hosts. 

Field Identification Guide - Phytophthora ramorum (Observatree website)

If you own or manage a woodland with larch or rhododendron, you should check these plants for symptoms of ramorum disease.

Report suspicious symptoms on any tree in Scotland to TreeAlert using the general enquiry webform.

Use TreeAlert (Forest Research website)

The web form asks for:

• your contact details
• the location of the sighting
• clear photographs of the affected tree(s) in context and the symptoms

For more information on what to include in your report, visit the ‘TreeAlert - what to do page’.

What do you need to make your report (Forest Research website)

Once you submit your report, diagnosticians at Forest Research will review it. They may contact you to request additional details.

Any suspected findings of regulated pests or pathogens, such as Phytophthora ramorum, will be sent to our Tree Health Officers for follow-up.

Phytophthora manual with sections about symptoms and biosecurity (Forest Research website)

We conduct aerial surveillance every year to identify new symptoms of ramorum disease across Scotland. 

Any newly suspected locations are followed up with ground surveys to collect samples for molecular diagnosis performed by Forest Research. 

A large proportion of larch in Scotland remains uninfected. Control actions remain necessary to slow down the rate, extent, and severity of disease spread to protect these trees.

Our action plan

In the winter of 2020/21, stakeholders from the forestry sector were invited to take part in a formal review of the 'Phytophthora ramorum on larch Action Plan'. 

We published the revised action plan in June 2021. Management for ramorum disease is conducted in three different Zones. 

Scottish Forestry Phytophthora ramorum Action Plan

Further information about the rationale and implementation of measures outlined in the Action Plan are detailed in our Question and Answer document. 

Frequently asked questions: Phytophthora ramorum management policy

The PAZ is the area where actions will have the greatest impact on controlling spread of ramorum disease. To date, outbreaks in the PAZ have been limited. 

Control efforts here have:

• successfully eradicated infections on larch
• safeguarded surrounding areas
• slowed disease spread

We are committed to prioritising surveys and the issue of Statutory Plant Health Notices (SPHNs) in the PAZ. 

The RRZ is the area where the spread and scale of infection are beyond what can be controlled locally. The main aim is to reduce the risk of ramorum disease to the sector.

To achieve this, SPHNs continue to be issued in the RRZ but with longer deadlines for compliance compared to the PAZ. 

This ensures consistency of control efforts between land owners to reduce build up of the disease in the environment.

Management Zone (MZ)

An area in south-west Scotland was at the heart of a major surge of ramorum disease on larch in 2013. 

The Plant Health (Forestry) (Phytophthora ramorum Management Zone) Order 2014 designated this area as a Management Zone.

Plant Health (Forestry) (Phytophthora ramorum Management Zone) Order 2014 (legislation.gov.uk website)

Within this Zone, the disease was too advanced to stop its spread within the area. Larch is being removed according to timelines given in existing Management Plans.

SPHNs for P. ramorum are generally not issued inside the Management Zone. This allows the phased removal of larch, as timber is harvested and processed.

Restrictions apply in Scotland to manage ramorum disease.

To prevent introduction and slow the spread of Phytophthora ramorum, SPHNs require felling of infected larch and all larch within a buffer zone (usually 250 m).  

The disease can also infect rhododendron species which then act as a source for further infection. 

Where ramorum disease is confirmed in rhododendrons, SPHNs will be issued requiring removal of all infected rhododendron and all rhododendron plants within a 2 metre buffer zone.

Specific biosecurity measures are required by SPHNs to prevent the transport, introduction and spread of ramorum disease from infected sites. 

Biosecurity requirements remain active for three years following the date of host removal under SPHN. 

This includes:

• cleaning machinery, tools and footwear
• limiting vehicular access
• providing signage

SPHN biosecurity requirements

Details of SPHN biosecurity requirements are provided in this guide: 

Biosecurity on sites served with a Statutory Plant Health Notice for Phytophthora ramorum on larch

You can also read research funded by the Plant Health Centre (Scotland’s Centre of Expertise).

Assessing spread of Phytophthoras in Scottish forests by recreational and harvesting activities using comparative qPCR and metabarcoding techniques (Plant Health Centre website)

Posters showing actions forestry workers and the public can take to help stop the spread of ramorum disease are available for download in two different sizes:

Forest workers

Phytophthora ramorum disease biosecurity poster for forestry workers - A3 size

Phytophthora ramorum disease biosecurity poster for forestry workers - A4 size
 

Public

Phytophthora ramorum disease biosecurity poster for the public - A3 size

Phytophthora ramorum disease biosecurity poster for the public - A4 size

Recommendations for restocking sites affected by ramorum disease with both conifer and broadleaf species are provided in this guidance document.

Advice on replanting sites affected by Phytophthora ramorum

Movement and processing licences in Scotland are issued by the Forestry Commission on behalf of Scottish Forestry.

Application forms are available on the Forest Research website.

Licences to move and process wood from trees with ramorum disease (Forest Research site)

Please contact the Forestry Commission plant health team with any enquiries or support needs relating to movement or processing licences.

Contact Forestry Commission plant health team (email)

You must apply for a movement licence to:

• remove wood from a site issued with an SPHN
• to move larch material from within the Management Zone to any site outside it

Wood can only go to a facility that holds a processing licence to handle it, both for:

• wood from SPHN sites
• wood moving from within the Management Zone to a site outside it

Ash dieback is widespread across Europe and the UK. Free guidance and toolkits are available to help landowners, managers and operators consider, prepare for, and manage the consequences of ash dieback.

Is ash dieback found in Scotland?

Ash dieback is:

• widely distributed throughout Scotland
• caused by a fungus (Hymenoscyphus fraxineus)

Import restrictions apply to ash originating in some parts of Europe as well as outside of Europe.

Scotland's ash woods (NatureScot website)

Maps of ash dieback distribution

You can access interactive and print maps showing the distribution of ash dieback across Scotland. These are available on the Forest Research website. 

Ash dieback (Forest Research website)

Ash dieback causes progressive leaf loss resulting, over time, in only sparse areas of foliage remaining in the tree crown. 

Ash dieback has killed ash trees across Europe. It is usually fatal in younger trees. 

Older trees more often die from the combined impact of ash dieback and other root pathogens such as the honey fungus (Armillaria mellea).

Scottish Forestry chair the Ash Dieback Risk Group Scotland. The group combines expertise from forestry and other sectors to:

• share knowledge
• consider experience with the disease
• discuss best practice in managing ash dieback

Management efforts focus on:

• mitigating safety risks from diseased trees
• letting disease-tolerant trees reproduce and spread naturally
• finding trees tolerant to ash dieback

The Living Ash Project aims to identify a large and diverse number of ash trees with good tolerance to ash dieback.

Living Ash Project website

Free guidance and toolkits are available to help landowners, managers and operators consider, prepare for, and manage the consequences of ash dieback.

These toolkits were developed in partnership with:

• the Ash Dieback Risk Group Scotland
• Scottish Forestry
• The Tree Council 

Ash dieback: a guide for tree owners in Scotland

An easy-to-read guide on ash dieback available for anyone responsible for ash trees in Scotland. 

The guidance is aimed at readers with little knowledge of ash dieback or tree management.

This provides a good starting point with advice on:

• identifying ash trees
• assessing their health
• deciding what management steps you might need

Ash Dieback: A Guide for Tree Owners in Scotland (Tree Council website)

An ash dieback action plan toolkit for landowners

We encourage all landowners to write an 'ash dieback action plan' to consider and prepare for ash dieback impacts. Plans can be prepared using The Tree Council toolkit. 

The toolkit includes:

• case studies from local authorities
• advice from other organisations based in Scotland

Ash Dieback: An Action Plan Toolkit for Scotland (Tree Council website)

Our ash dieback guidance is available in three complementary documents.

Managing individual ash trees 

This guidance applies to the management of individual or small groups of ash trees. It applies to any situation where infected ash trees pose a risk to public safety or property.

The guidance includes:

• example survey sheets for monitoring ash trees
• information about felling permissions
• information about tree protection legislation
• restocking advice

Guidance on the management of individual ash trees affected by ash dieback in Scotland

Managing woodlands affected by ash dieback

This guidance applies to woodlands with larger numbers of ash trees. The guidance helps landowners and managers:

• plan for and manage ash dieback at woodland scale
• consider ash dieback in the context of woodland management goals

A decision tool is included to help you make management decisions where timber production is a primary goal. 

The guidance also includes advice developed in partnership with NatureScot about managing native ash woods and ash trees on Sites of Special Scientific Interest.

The management of woodlands affected by ash dieback (Hymenoscyphus fraxineus) in Scotland

Supplementary guidance note for ash works in Scotland

Are you working on trees infected with ash dieback? This guidance provides information to complement your existing risk assessments, and health and safety practices. 

This guidance shares:

• information about how ash dieback can affect wood structure
• observations and practical considerations from experienced contractors and professional organisations working on infected ash trees
• examples of how tree work methods were adapted to reduce risks to people working on infected trees

Supplementary guidance note for ash works in Scotland (Tree Council website)