The Arboricultural Association is committed to promoting the implementation and understanding of good biosecurity practices to assist in safeguarding the future of our trees from the introduction and spread of harmful organisms. This statement outlines some basic biosecurity principles that should be adopted to reduce the unwanted introduction and spread of tree pests, diseases and invasive tree species:
1. Operatives and organisations undertaking work on or around trees should consider the reasonably foreseeable consequences of their activities. Adopting biosecurity risk assessment processes and policy commitments are prudent first steps.

2. Those undertaking work on or around trees have a responsibility to implement routine biosecurity control measures for all sites and specific measures for higher risk sites highlighted by the biosecurity risk assessment process. This should include the cleaning and disinfection of clothing, PPE, tools, equipment and vehicles.

3. Arboricultural operations such as pruning, felling and planting should be planned, managed and supervised to minimise the movement of arisings and soil. All arisings must be appropriately disposed of.

4. Organisations working on sites with trees should ensure that their operatives understand biosecurity issues and comply to adopted biosecurity measures. Training, guidance and supervision should be provided when necessary.

5. Anyone planning, designing, or implementing planting projects should aspire to source home grown and nursed specimens avoiding, where possible, directly imported stock to reduce the risk of introduction of pests and diseases.

6. Anyone responsible for tree supply should ensure that trees and associated soil are supplied to customers free of pest and disease at all points in the supply chain. Consideration must be given to the latency period* and life cycles of all pests and diseases in order to achieve this. Special attention must be given to imported stock.

7. Good urban forestry practice involves managing tree populations to increase species and genetic diversity by focusing on the establishment and maintenance of trees with qualities suited to the site and the prevailing climatic conditions. Additionally, good species composition, age structure, stock quality and condition will help reduce the future loss of trees due to the introduction, hybridisation or spread of tree pests and diseases.

8. Anyone involved with trees must encourage and promote adherence to these guiding principles and above all act as role models in this regard.

* A period of time where a plant may be infected or infested by a particular pest or disease but where there are no physical symptoms that indicate ill health.

If you are unsure about any of these guiding principles do not ignore them. More information and guidance can be found from the following sources: Arboricultural Association www.trees.org.uk