What is Arboricultural Biosecurity and why is it important?

We are all becoming increasingly aware that our native tree species can come under threat from foreign pests and pathogens. Arboricultural biosecurity is moving up the priority list for all companies and groups that manage large stocks of trees. We have seen dramatic fails in the past, which certain tree species decimated by non-native invasive pests and pathogens.

Undertaking regular tree surveys is an important strategy in protecting UK native trees. Modern technology has made tree surveys quicker, more detailed and more robust. This enables surveyors to quickly identify if a tree has and defects or is suffering from invasive pests and pathogens so that action can be taken quickly to deal with the issue.

Such arboricultural biosecurity was not around in previous epidemics. For example Great Britain was devastated by Dutch Elm Disease back in the 1970s. A fungal disease spread by a bark beetle this disease first made its UK appearance in the 1920s. This was a mild form, however a more virulent strain arrived in the late 60s’ brought to the UK along with a shipment of logs from North America. The consequences were devastating and by 1975 millions of elm trees had died, dramatically changing the face of the British countryside. Tree surveys were scant in those days and were not looking for invasive pests and pathogens so the problem grew without it really being noticed until it was too late.

More recently we have seen the widespread damage caused by the leaf mining insect Cameraria ohridella to horse chestnut trees. This leaf miner was known to occur in the Balkans in the late 19th century, but only started to spread rapidly westward from around 1989. The result is that horse chestnut leaves turn brown and miserable in early summer and the infestation saps vigour and conker production.  This is why regular tree surveys are becoming increasingly important and arboricultural biosecurity is needed to prevent bringing infected trees and plants into the country.

So severe are the implications of invasive pests and pathogens that work has been undertaken to identify, detect, and prevent them from entering the UK. But awareness in the general population is still low, and identification is difficult to the untrained eye. Developing arboricultural biosecurity strategies is therefore key to the protection of UK trees.


The Arboricultural Association has published a detailed report as an industry guide to enable those who work with trees at all levels to become educated and informed on the subject of arboricultural biosecurity, actions to take and responsibilities.

As a company, PBA Consulting is involved in large tree surveys for companies and organisations such as TfL and large Housing Associations, some of whom have in excess of 12,000 trees.  We feel that the Arboricultural Association’s Arboricultural Biosecurity Guide should be promoted within the industry, and to all parties interested in the health of our countryside. The report looks at the economic, environmental and societal costs of damage to the trees under threat. It reviews the challenges that our contract landscaping clients face in securing (buying) trees for new landscaping projects, and the need to implement biosecurity strategies to ward against invasive pests and pathogens.

Various insects and diseases have been identified as possible threats, and while not yet present in the UK it is important undertand and be able to identify these invasive pests and pathogens. We all need to work together to increase the UKs biosecurity in order to prevent another catastrophe.

The Arboricultural Association’s Arboricultural Biosecurity Guide is a must read for all those engaged with managing and protecting the tree stock of the UK and we would urge you to make some time to sit down with a hot cup of coffee, and read this Arboricultural Association’s Arboricultural Biosecurity Guide. 


Fiona Aucott 7/2/2019