LI Plant Health and Biosecurity Newsletter – Summer 2018

In this edition

Big issues

Defra’s Tree Health Resilience Strategy launched 25 May 2018, coinciding with Chelsea Flower Show and the Action Oak multi-agency initiative. The 63-page Tree Health Strategy, forming part of the government’s 25 Year Environment Plan, sweeps up many pre-existing government and agency policies, approaches and initiatives, and adds proposals for coherence. The LI, through the Biosecurity Group, is a stakeholder member of Defra’s Tree Health Group.

The resilience circle, from Defra’s Tree Health Resilience Strategy, p34

The Tree Council and Fera will shortly publish a toolkit to help local authorities develop Local Action Plans to strategically manage pest and disease threats. We will feature this in our next newsletter.

Defra’s consultation on the future for food, farming and the environment is now closed. Read the LI’s response to this consultation.

Forestry Commission’s company Forest Holidays (of which FC retains 14% share) recently sold 42% share to Phoenix Private Equity Company – with permission to develop chalets on up to 30 sites at any one time.

Simon Jenkins at the Guardian writes: ‘It should know better.’

A £220 million Clean Air Fund to tackle roadside emissions is part of a £260 million plus package to improve air quality.

In related news, First Steps in Urban Air Quality – new guidance from Trees and Design Action Group (TDAG) UK by Ferranti, E.J.S., MacKenzie, A.R., Ashworth K., and Hewitt C.N., 2017 – is now available as a free download.


The first of the Northern Forest’s 50 million trees were planted in May 2018 at the Woodland Trust’s Smithills Estate near Bolton. The project, which will cost some £500 million, was conceived by the Woodland Trust with five community forest projects across the area. The government has provided £5.7 million to kick-start work to green 120 miles from Liverpool to Hull over the next 25 years.

Interestingly , there is a bit of a discussion going on about sourcing seed from native vs. imported species, the latter with a provenance to ensure those trees will be better adapted to climate change.

(See also Paul Nolan’s article in the Spring 2018 edition of Landscape (p58).)

Pollinator in action

Other items

  • EU’s subsidy system, benefiting big farming rather than sustainability, needs to change to prevent ongoing collapse in birds and insect numbers, warn green groups. From
  • Radical changes in thinking about rural communities and the natural environment are needed, says NERC. From
  • Biodiversity continues its dangerous decline in every region of the world, Scientists warn – significantly reducing nature’s capacity to contribute to people’s well-being. From
  • Eric Holthaus offers sobering thoughts on forests and last-ditch efforts to save them from climate change worldwide. From
  • Extreme weather events are now happening four times more than in 1980, according to a European science paper. From

Plant health

  • Plant Assurance Scheme – an introduction from Raoul Curtis-Machin, outgoing Director of Horticulture at HTA. (Speech at Highgrove plant health conference, 1 February 2018.)
  • The government’s plant passports guidance, Issuing plant passports to trade plants in the EU, was updated in March. We often refer to this outline guide for landscape professionals.
  • Expert advisory panel report and discussion on phyto-threats and research progress, October 2017 – Phytophthora distribution, diversity and management in UK nursery systems. In a trial sample of nurseries, Phytophthora was more prolific than expected. This piece highlights pointers to look out for in nursery visits, feasibility analyses, and development of ‘best practice’ criteria. A survey of public plant-buying habits showed the most popular places to purchase plants were retailers and large garden centres, but these places were also viewed as being less concerned (than nurseries) with biosecurity.

Pests and diseases update

Oak processionary moth

OPM Management Zones have been adjusted as of May 2018, with an expanded core area, and control or buffer zones covering an extensive area encircling London, with the rest of the country designated as a Protection Zone (PZ).

All oak moving into and within the PZ requires a plant passport regardless of the size of the consignment, and this document must be retained for at least a year. Outside the PZ, plants passports are still required if imported trees are intended for further propagation or growing on. We advise that you inspect this paperwork thoroughly and carry out careful sourcing, to encourage best practice within the supply chain and improve traceability.

Almost 600 statutory plant health notices have been sent out to control OPM this year. Following a recent sighting of OPM on imported oaks we are all required to be vigilant at every stage, and to perform visual checks of your material and to report any suspicious signs of pests or diseases to a Plant Health Inspector as soon as possible.

Notes from OPM Evidence and Policy Workshop – St Matthew’s House, London, 2 May 2018 (PDF, 406 KB)

More information at

Sweet chestnut blight (Cryphonectria parasitica)

Since 2016-17 the following outbreaks have occurred in the UK:

  • 8 sites in Devon
  • 1 site in Dorset
  • 1 site in Berkshire
  • 8 sites in East London
  • 1 site in Leicester

The UK is a Protected Zone for C. parasitica, and movement of plants intended for planting (including seed), and round timber and isolated bark into countries with PZ status is not permitted unless the plants, timber or bark have been passported and are accompanied by an official statement to show that they either originate in a pest-free area, or (in the case of timber and bark) have been kiln dried, or that the bark has been fumigated.

More information at

Phytopthora ramorum

Two cases of P. ramorum were identified in Sitka spruce in Scotland last autumn. CONFOR has issued an update.

Round headed apple tree borer (Saperda candida)

The Forestry Commission has prepared new national legislation to protect the EU from the threat of the round-headed apple tree borer. The legislation will regulate a number of wood products and a wide range of trees that are hosts (food trees) for the beetle. (Host plants include amelanchier.)

Ash dieback

A recently published study suggests that Ash dieback has been in the UK for longer than previously thought.

Pollinator in action

Other items

Polluter paysWhat landscape professionals should know regarding liability, contracts and best practice.

The RFS has posted a good introduction to tree pests and diseases on its blog, to be regularly updated.

When a new pathogen rears its head, and resources are limited, is it best to try to stamp it out quickly – or wait and see? The Control Smart Algorithm (CSA) resolves the trade-off between the competing advantages of controlling as soon as possible and controlling later when more information has become available.

Natives and aliens

  • While some organisations in the UK advocate planting only trees of local provenance, others in forestry believe that, with climate change a reality, we should be doing more ‘assisted migration‘ – bringing in material from latitudes further south to preempt a warmer climate here. The jury is out, and it may take a lifetime to learn the verdict.
  • Invasive species week, on 22-29 March, encouraged river users to think about non-native species and aquatic plants such as floating pennywort.
  • Invitation to LI members: If any members would be interested to report back to the LI Biosecurity Group specifically on invasive species please contact with details of your interest.

LI biosecurity survey – results coming soon

The Landscape Institute- and University of Sheffield-run survey, Landscape architects and biosecurity: a survey to identify the role of designers in plant health, is closed. The findings will be reported in an article in Landscape and in our next newsletter. In the meantime, a big thank you to everyone who took part!


New e-learning module launched. Forestry Commission has expanded its suite of online e-learning modules on plant health and biosecurity topics. The latest concerns the import and export requirements for wood packaging materials (WPM). It can be accessed via the free Forestry Commission Digital Learning portal. (Signup required for new users.)

FC and FCR newsletters (Scotland and England)

Exciting uses for timber

  • An amazing range of new wood-based products is included in this article from the Finnish Forestry Association.
  • Continued awareness among designers, architects and engineers of the potential for mass timber will see more projects opt for wood, says Think Wood.

If you have any comments or news to contribute to our next plant health and biosecurity newsletter, please do get in touch with us via

LI Plant Health and Biosecurity newsletter produced by: Tim Arkell, Ben Brace, Annabel Downs, Roger Kent, Colin Moore, Alan Simson, Harry Watkins (Biosecurity Working Group chair) and Gemma Worswick