Forestry

The sector represents a major component of Scotland’s rural economy – providing significant employment and raw materials for wood processing industries.  Sustainable forest management seeks to deliver these economic benefits alongside important ecosystem services such as carbon sequestration and flood mitigation, provision of wildlife habitat and opportunities for recreation and a range of leisure activities.  Pests and diseases threaten the continued long-term delivery of these benefits.

The forest area of Scotland expanded during the twentieth century through the efforts of the Forestry Commission and private owners to develop a domestic wood supply and provide rural employment.  A number of introduced species, such as Sitka spruce, were key to afforestation of marginal agricultural sites and now are central to the wood processing industry.  Woodland now occupies approximately 17% of the land area of Scotland and provides 44% of the GB softwood harvest, producing about 1.5 million m3 of sawn softwood.  Plant health threats to the forestry sector include a number of recently introduced pests and diseases (e.g. Phytophthora ramorum, pine tree lappet moth, ash die-back), on-going management of endemic ones (e.g. large pine weevil and Heterobasidium annosum) and risks of those yet to arrive (emerald ash borer, Ips typographus and many other organisms potentially introduced through trade in plants, wood and packaging).

Projects

Project Lead: David Cooke
Species of the genus Phytophthora are of particular concern to the health of Scotland’s plants due to their destructive potential and ability to spread via cryptic infection on traded plants. The genus Phytophthora currently comprises over 200 species and there is a current gap in the evidence in estimating and acting on these threats in a proportional and measured manner to both prevent further imports of Phytophthora and to objectively assess the risk of any new findings.

This project will (i) review and collate the contemporary data and evidence on Phytophthora discovery, species description and traits; (ii) use the collated data to horizon-scan and predict disease threats in Scotland and (iii) model and map the greatest threats to plants in specific key habitats. The findings will be compiled into a report on the updated risks with recommendations for enhancing preparedness through risk-based prioritisation of hosts and habitats for targeted surveillance to promote earlier detection of Phytophthora species. Although the project will consider plants in agriculture, forestry, horticulture and natural ecosystems across Scotland, the principal focus will be on the risks to relatively under-studied plant hosts in the natural environment.

This project was selected for funding from the Project Call: “Enhancing preparedness against pests and diseases: plugging evidence gaps for Scotland”.

Image credit: Glensaugh ©The James Hutton Institute
Project Lead: Matt Elliot
A best practice waste management guidance document was produced during PHC2021/02 (Identifying the plant health risks associated with plant waste disposal and peat-free growing media and developing best practice guidance for waste disposal and composting across sectors) to help organisations and businesses manage their plant waste effectively and reduce both the individual business risks, and the wider risks to Scotland’s plant health. However, Project PHC2021/02 identified that there were significant barriers to the uptake of better waste management practices, so an additional programme of knowledge exchange was funded by the Plant Health Centre with the aim of:

1. Sharing the best practice for waste management with those managing waste in plant nurseries, gardens, parks and other plant handling businesses.
2. Ensuring the best practice guidance is available for those applying to become Plant Healthy certified.
3. Producing a peer-reviewed publication on plant waste management to ensure the broadest reach with plant health experts.
Project Lead: Sarah Green
This project aims to utilise existing Scottish resources to fill in key evidence gaps so that threats to Caledonian Scots pine can be better understood, and potential mitigating measures identified. PHC2022/07 was proposed due to unusual disease symptoms on Caledonian Scots pine (Pinus sylvestris) located in the Aviemore area of Scotland having recently been investigated by the Tree Health Diagnostic and Advisory Service of Forest Research.

This project will carry out a targeted survey of Caledonian pine in Scotland to assess extent and incidence of symptoms and to collect samples; compare and identify to species level isolates of potential causal agents collected from native Scots pine and determine their phylogenetic placement and genetic diversity; develop an effective inoculation method through studies of the infection process on needles and woody tissues of Scots pine, and; determine the pathogenicity of the causal agent(s) on Scottish provenances of Scots pine.

This project was selected for funding from the Project Call: “Enhancing preparedness against pests and diseases: plugging evidence gaps for Scotland”.
Project Lead: Harry Watkins
PHC2022/06 builds on an outcome from a previous PHC project (PHC2019/05) which created GIbase 1.0: A database of green infrastructure plant species in England and Scotland, which was built by searching local authority planning portals for plant specifications associated with Green Infrastructure projects.

This project will extend the database, creating GIbase 2.0., establishing search functions for planning portals across Scotland, automatically generating notifications of projects that meet specific criteria relating to project scale and type. This will allow both higher resolution data to be recorded and also ensure that GIbase 2.0 captures the most current schemes under development or in early-stage planning.

This project will Map the diversity and abundance of plant species used in green infrastructure across Scotland, and record this data in GIbase 2.0. It will use the UK PHRR to create relative risk profiles for each plant species, and, for commonly planted species, create high quality data sheets using published research, providing a valuable asset to policy-makers, local planning authorities, Green Infrastructure designers and developers.

This project was selected for funding from the Project Call: “Enhancing preparedness against pests and diseases: plugging evidence gaps for Scotland”.
Project Lead: Adam Kleczkowski
This project seeks clarity on how Scottish Sitka spruce forests might respond to further increases in pressure from climate change and existing or new pests and their potential synergistic effects.

Building on an existing decision support tool developed as part of a previous PHC funded project (PHC2018/14), the project will produce an updated modelling framework with key processes and parametrisations for D. micans (present in Scotland) and an initial assessment for I. typographus (invasive) risks under changing climate.

Initial economic analysis of the impact of different scenarios will also be produced, as well as pathways for incorporating future research results. The project was jointly developed with Scottish Forestry and Forestry and Land Scotland who will be involved throughout the process, particularly in developing the policy advice and bringing in industry views, including during workshops that will assess the modelling framework, with recommendations being incorporated into the final version.

This project was selected for funding from the Project Call: “Enhancing preparedness against pests and diseases: plugging evidence gaps for Scotland”.
Project Lead: Helen Rees
Previous PHC projects found that biocontrol is one of the elements of Integrated Pest Management (IPM) with a role to play in mitigating pesticide withdrawals. However, it is currently unclear how practical biocontrol is as a suitable alternative to pesticides in Scotland, what the opportunities are for deployment across different sectors and what barriers exist to uptake (include regulatory).

Research on biocontrol agents is required to understand a) what relevant previous work has taken place, b) the potential benefits for agricultural, horticultural and forestry applications in Scotland, and c) is the current risk assessment framework and regulatory system fit for purpose?

This project will improve our understanding of the potential of biocontrol agents in Scottish production systems and gardens; synthesising findings from workshops with stakeholders and literature review.
Project Lead: Sarah Wynn
Insecticides are commonly used in Scottish agricultural, horticultural, forestry production, and for amenity and natural environment management purposes. Over the last 10 years, approximately 50% of UK insecticide active substances have been withdrawn due to increasing concern over human health and environmental impacts. Some of these losses will be mitigated by using alternatives but their practicality and cost under Scottish conditions is unknown. Given the likelihood that regulatory restrictions on pesticide usage will not be reduced, widespread adoption of IPM might offer a way to reduce reliance upon at risk pesticides.

This project will deliver an expert review of available literature to identify the insecticides of concern to Scotland and their association with current practices. This targeted review will identify available alternatives and their efficacy, and any interdependencies and evidence gaps will be identified. A key outcome of this call will be case studies of the alternative methods adopted by stakeholders to mitigate the impact of insecticide withdrawal, combined with desk-based and expert opinion and analysis on their efficacy, practicality and cost.
Project Lead: Matt Elliot
The Plant Health Centre was commissioned by the Scottish Government to review evidence relating to the potential of new gene editing technologies to address plant health issues in Scotland, with potential benefits, barriers to deployment and dis-benefits noted
Project Lead: Mariella Marzano
Three projects (PHC2019/04/05/06) were conducted in 2020/21 that investigated large-scale biosecurity risks to Scotland from several supply-chains and planting approaches. This project was commissioned, within the original scope of the aforementioned projects, to conduct further research with a strong likelihood of strengthening and expanding their findings. This project seeks to engage with hard-to-reach actors and the wider sector through their membership organisations.

PHC2021/08 will implement an Action Research approach, delivered through workshops co-designed with network organisations, to better understand current plant biosecurity risks in several sectors, to identify their plant health knowledge needs, and to begin to embed biosecurity training within existing organisations, programmes and processes.

The outcomes of the project will be:
• An enhanced understanding of the knowledge and training needs of different sectors and the identification of biosecurity actions that will fill some of the gaps identified by PHC2019/04/05/06
• The identification of further training needs and potential approaches to address the problems identified
• A legacy of close working relationships between the PHC and several network organisations, key to future plant biosecurity research or training delivery activities
Project Lead: Steven Hendry
Originally raised as a plant health issue of potential concern, the health of Alder trees in Scotland was initially investigated in project PHC2019/09: Health status of Alder in Scotland. This preliminary study found that there could be a legitimate concern over Alder that may have complex causes (several biotic and abiotic stresses were noted), and the timeline of these health issues (gradual or rapid) was unclear. Further scoping and examination of the problem by established experts was recommended, leading to this project. The project will conduct:
• Expert visitation of sites to seek evidence of problems with alder health, gain some understanding as to possible causes, and identify key dimensions of a thorough study should this prove warranted. Lab work to confirm field diagnoses.
• Preliminary citizen science request inviting site-specific records of concern over alder health (potentially via the trained Observatree volunteer network to gather data), with analysis to identify any geographic clustering.
• Produce recommendations for further work including; refined survey methodologies for widespread application by interested organisations; identification of potential candidate sites for detailed study over time, and; a discussion document on risks to existing alder of expansion of riparian woodland.

Publications

Forestry, Environment | Final Report and Policy Document

Assessing spread of Phytophthoras in Scottish forests by recreational and harvesting activities using comparative qPCR and metabarcoding techniques

February 2024

Pathogens from the genus Phytophthora pose some of the greatest threats to tree health and are likely to become increasingly prevalent in the UK as the climate becomes warmer and wetter. This project added new data based on a DNA metabarcoding approach to determine the Phytophthora species diversity in soil samples and sampled material from timber harvesting operations alongside those of recreational activities.

Forestry, Horticulture, Environment | Final Report and Policy Document

Action Research to gain a deeper understanding of large-scale biosecurity risks to Scotland

December 2023

This project has developed a systems approach, in the context of plant health biosecurity risks in the retail, infrastructure landscaping and planting in the natural environment, to facilitate further understanding of key organisations and identify general and specific leverage points at which interventions could have a significant effect on the system.

Forestry, Environment | Final Report and Policy Document

Preliminary investigation into the threat of Bronze Birch Borer (BBB - Agrilus anxius) to Scotland

August 2023

The Bronze Birch Borer (BBB, Agrilus anxius) is a major threat to birch trees. This project had co-funding from Scottish Forestry and NatureScot and undertook evidence gathering to assess the threat BBB poses to Scotland, inform risk assessment, surveillance and contingency planning, and identify key risks and knowledge gaps.

Forestry, Horticulture, Agriculture, Environment | Final Report and Policy Document

A targeted analysis of the impact of insecticide withdrawals in Scotland, in the context of alternative control options

July 2023

Insecticides are commonly used in Scottish agricultural, horticultural, forestry production, and for amenity and natural environment management purposes.  Over the last 10 years, approximately 50% of UK insecticide active substances have been withdrawn due to increasing concern over human health and environmental impacts.  Some of these losses will be mitigated by using alternatives but their practicality and cost under Scottish conditions is unknown.  This project analysed current crop production patterns and insecticide use in combination with how likely different insecticides are to be withdrawn and provided stakeholder views on the impacts of any such losses on their industry, including other control methods that may be adopted.

PHC Annual Report 2022-2023

July 2023

The Plant Health Centre works with Scottish Government, public bodies and stakeholders to provide scientific evidence to help them make important decisions about pests and pathogens that threaten Scotland the most.  Over the past 12 months we have delivered a consistent programme of stakeholder engagement and project commissioning, which are detailed in our annual report. 

Forestry, Horticulture, Agriculture, Environment | Final Report and Policy Document

Biosecurity practices to support plant health: a review of knowledge and practice

March 2023

This research investigated plant biosecurity risks from site visitors, tools & equipment, and large machinery. In addition to reviewing published guidance, UK businesses and organisations were engaged via questionnaires and interviews to explore how these aspects of biosecurity are understood and what procedures may be in place to address them.

Forestry, Horticulture, Environment | Final Report and Policy Document

Identifying the plant health risks associated with plant waste disposal and peat-free growing media and developing best practice guidance for waste disposal and composting across sectors

March 2023

This research focussed on two areas of biosecurity that provide significant risk to plant businesses and the wider environment in Scotland, i) plant waste management, and ii) the constituents of reduced-peat and peat-free growing media.

Enhancing the Plant Health Centre’s communication with stakeholders

February 2023

This project was commissioned to implement a selection of the recommendations made in the PHC stakeholder engagement strategy and communication plan. The team developed strategies to manage time and resources of the Plant Health Centre more efficiently regarding communication of outputs, general information on activities, aims and current issues related to plant health.

Forestry, Horticulture, Agriculture, Environment | Final Report and Policy Document

Improving knowledge of Xylella fastidiosa vector ecology: modelling vector occurrence and abundance in the wider landscape in Scotland

May 2022

If introduced to the UK, the insect-vectored, bacterial plant pathogen Xylella fastidiosa could be a serious threat to trees and other plants. There is a lack of knowledge about the ecology and distributions of Xylella vectors in Scotland and the potential effects of this on any outbreak of the disease, which this project aimed to address.

Assessment of large-scale biosecurity risks to Scotland

December 2021

PHC commissioned an assessment of large-scale biosecurity risks with a focus on three areas of concern:

  1. non-specialist and online horticulture sales;
  2. landscaping and infrastructure;
  3. planting for environmental benefits.

An additional area was the potential for modelling to support decision making across these areas of concern.  This policy report summaries each report and highlights the key findings and suggested actions.  

Assessment of large-scale plant biosecurity risks to Scotland from non-specialist and online horticultural sales

October 2021

This project focused on an initial exploration of tree and plant biosecurity risks to Scotland arising from large-scale movement of plants via non-specialist (those for which plants are not their primary product type, e.g., supermarkets, DIY and lifestyle stores) and online plant retailers. By better understanding the characteristics of these retailer types, the plant health behaviours they undertake, and the challenges they face, potential avenues were offered for greater engagement and collaboration on biosecurity with this important, but understudied and hard to reach sector.

Assessment of plant biosecurity risks to Scotland from large scale plantings for landscaping and infra-structure projects

October 2021

Planting for large-scale landscaping and infrastructure can typically involve tens of thousands of individual plants, potentially threatening plant health in Scotland due to the biosecurity risks of imports and widespread planting of infested or diseased plants. This project aimed to understand the extent and means to mitigate against such plant biosecurity risks with a focus on mapping the pathways from plant specification through to planting and establishment and highlight different biosecurity awareness for actors, in decision-making and procurement processes.

Assessment of plant biosecurity risks to Scotland from large scale tree plantings for environmental benefits

October 2021

This report features five case studies from across Scotland and examines risks associated with large scale tree planting schemes, levels of awareness around pests and diseases, and how the decisions and actions of those involved can serve to reduce or exacerbate pest and disease related threats and long-term tree health. Each case study was unique in respect to their combination of location, site conditions, ownership, management objectives, species choice, supply chains and management activities. By highlighting best practice and lessons learned, it was hoped to ensure that future planting schemes can be successful and, importantly, reduce the likelihood of pests and diseases being introduced and spread into the wider environment.

The potential of ecological and epidemiological models to inform assessment and mitigation of biosecurity risks arising from large scale planting

October 2021

Large scale planting projects linked to infra-structure such as transport networks and major housing projects or to planting for environmental benefits (e.g., urban greening, woodland restoration) pose high biosecurity risks due to the high number and types of plants involved. This report focusses on whether and how ecological and epidemiological model frameworks can inform assessment and mitigation of biosecurity risks from large scale planting using a combination of literature review and stakeholder engagement.  The project aimed to identify priority steps to develop more useful models and tools for assessing biosecurity risks from planting in the future.

Forestry, Environment | Policy Document

Assessment of suitability for EAB invasion for Scotland and the UK

June 2021

Emerald Ash Borer (EAB) has become a significant threat to ash trees in several countries (including USA and Russia) but is not yet present in the UK. We quantified climate and ecological factors affecting EAB suitability using native range data and conclude that southern England is a highly suitable habitat for EAB. Although currently less favourable, we project that Scotland will become increasingly suitable for EAB under climate change. Thus, EAB could threaten Scotland via trade with areas where it is present or, through spread from populations if established in England or Western Europe. Rapid spread of EAB has been observed in its US invasion. We therefore recommend further study and vigilance against EAB introductions into the UK.

Forestry, Horticulture, Environment | Final Report and Policy Document

Metabarcoding analysis of Phytophthora diversity in spore traps and implications for disease forecasting in the P. ramorum management zone

May 2021

Surveillance and monitoring of airborne pathogens is a key tool in the management of healthy forests and controlling disease outbreaks. A Scottish Forestry-funded project was carried out in autumn 2019 to validate different spore-trapping techniques for monitoring airborne P. ramorum inoculum using a species-specific qPCR assay. This project aimed to add further value to the Scottish Forestry project by investigating the suitability of DNA metabarcoding for screening spore trap samples for P. ramorum and other Phytophthora species, seeking early data for aerially dispersed Phytophthora species that may become problematic in UK forests. The study highlighted the value of both monitoring P. ramorum dispersal and detecting other Phytophthora species, to predict and understand changes in disease severity in UK tree host species. Recommendations included that the use of both rain and wind-borne inoculum capture methods might be advantageous due to the variety of weather conditions under which inoculum can disperse.  Lineage testing in Southwest Scotland should be carried out to look at the prevalence of lineage EU1 in the EU2 area and to monitor for presence of North American lineages. Development of a new DNA barcode more specific to Phytophthora would be beneficial.

Forestry, Horticulture, Agriculture, Environment | Final Report and Policy Document

PHC2020/09: Economic Impact of Pesticide Withdrawals to Scotland, with Case Studies

March 2021

Chemical forms of plant protection are widely used in Scottish agricultural, horticultural and forestry production plus for amenity and natural environment management purposes.  The availability and use of active substances in pesticides are closely regulated and increasing concern over human health and environmental impacts has led to a greater likelihood that some existing approvals will be withdrawn and/or that approvals for new products will not be granted.  Potential impacts from withdrawal of these pesticides are of policy interest and this summary report builds on the data and results from project PHC2018/15 (Potential impacts arising from pesticide withdrawals to Scotland’s plant health) and uses case studies to understand the likely magnitude and distribution of potential impacts and how they may be mitigated. 

PHC2018/15: Potential Impacts Arising from Pesticide Withdrawals to Scotland’s Plant Health

November 2020

The use of pesticides to manage plant pests and diseases is a key management intervention across plant health sectors, particularly in agriculture, horticulture and commercial forestry production. Pesticide withdrawals through legislation, coupled with resistance development and their impact on plant health, have emerged as key concerns for Scottish plant health stakeholders.  This project quantifies the impacts on Scottish plant health that will arise from pesticide withdrawal scenarios and sets this in the context and time frame of alternative management tools. 

Impact of climate change on the spread of pests and diseases in Scotland

June 2020

This project constructed a modelling framework which combined epidemiological and economic modelling.  The modelling framework was used to study predictions of spread and economic impact of pests which are not currently in the UK, including Xylella fastidiosa, Candidatus Liberibacter solanacearum (Zebra chip) and Ips typographus (Eight toothed Spruce Bark Beetle). 

Impact:  A web/desktop application is available to the PHC and Scottish Government to analyse the effects of climate change on the spread and economic impact of new threats. 

Forestry | Final Report

Modelling Framework for invasive pests: Emerald ash borer as a case study

June 2020

This project investigated whether modelling could aid preparation for a potential bark beetle and wood borer invasion of Scotland. This was achieved by: (i) reviewing suitability of modelling results and frameworks in literature; (ii) recommendations on how these could be rapidly adapted for Scottish and UK plant health context and (iii) case study on Emerald ash borer to exemplify approach.

Expansion of PHC Online Plant Health Resources

May 2020

This project has expanded the PHC online Resource Bank for plant health threats to the Natural Environment sector in Scotland to include information sources for the remaining three sectors (Forestry, Agriculture and Horticulture). Information sources for Forestry, Agriculture and Horticulture were compiled and evaluated, and a Knowledge Bank relevant to each sector is now online at the PHC website, creating a comprehensive and unique signposting resource for plant health information with relevance to Scotland.

 

Forestry, Environment | PHC Pest Review

Threat: Bud worm

Authors: Chris Quine
October 2019

Status, Scottish specific issues, Plant Health Centre perspective and Key priorities and recommendations concerning the threat from the Eastern spruce budworm (Choristoneura fumiferana), Western spruce budworm (C. freeman) and  Black headed budworm (Acleris gloverana and A. variana) to Scotland

Forestry, Environment | Final Report and Policy Document

Development of an online, user friendly plant health resource bank for the Scottish Natural Environment

August 2019

The aim of the project PHC2018/11 was to compile a resource to be embedded within the Scottish Plant Health Centre (PHC) website, with the following three main purposes: 1) To direct users to existing, comprehensive and reliable plant health information resources; 2) To provide information on selected plant health threats to the natural environment, particularly invasive non-native species; and 3) To direct users to appropriate government agencies and resources and advise users on steps to take should a suspected statutory pest or disease be encountered.

Webpages have been developed which provide the following:

1) a listing of the first most pressing plant health threats to the natural environment in Scotland;

2) a user-friendly web template, populated with links to information about these major threats and other topics relevant to plant health in the Scottish natural environment; and

3) summary pages providing guidance on biosecurity and control of diseases in this sector, for which other resources were not easily available.

Forestry, Horticulture, Agriculture, Environment | Final Report and Policy Document

The use of mobile technology to enhance plant health monitoring and awareness in Scotland

August 2019

The aim of the project was to review existing websites and smartphone apps currently available and applied in the plant health sector and to assemble a detailed overview covering the following points:

  • What options are available in terms of mobile software applications for plant health?
  • What is their primary purpose?
  • Who is the target audience (growers, plant health professionals, citizen science, …)?
  • Which plant health sectors do they cover?
  • Are they reliable and accurate?
  • Is information submitted to a central database? If so, how is this information used?
  • Could they be used globally, or are they limited to certain geographic regions?

Difficult choices to protect gardens and the environment

Authors: Katy Hayden
September 2018

Heritage gardens play an important role in plant conservation. They house collections gathered over decades or even hundreds of years, including varieties of plants that may be overlooked elsewhere, fostering heirloom varieties and preserving biological diversity that is the raw material of adaptation. As well as being beautiful and tranquil sites of cultural heritage, these ex-situ resources are treasure troves of biological diversity. Arduaine Gardens shows us that tough choices can be necessary and important to preserve these collections and the surrounding environment.