Trees and woodland are essential for the UK populations of bats. Woodland provides shelter and foraging habitats for bats, but perhaps the most significant use of trees by bats is as roosts. Most species in the UK will roost in trees, and some species rely exclusively on trees for roost sites. The legal protection afforded to bats and their roosts is strict and local authorities or the competent authority often require the likelihood of roosts being present to be considered before undertaking tree works. Tree works on development sites can have permanent or long-term impacts and national good practise survey guidelines (published by the Bat Conservation Trust) states, “where this type of work could impact on bats, it is essential that trees on and around the site are assessed comprehensively”.

Assessing trees for bat roosts can require considerable effort because the features that bats use can often be small, high in the canopy of the tree and obscured by foliage. That’s great for predator avoidance, but presents ecologists with difficulties when surveying. There are several methods to survey trees and the level of survey is somewhat dependent on the value of the habitat for bats and the extent of the impacts.

Hugh Dixon, consultant ecologist at Capita Symons said: “A climb and inspect survey by Baker Consultants in March enabled us to identify a tree roost at an early stage of our development. We subsequently applied for an EPS licence and were able to fell the tree without causing delay to the programme of works. This saved money on the project and proved to be an effective method of surveying."

At Baker Consultants we have bat ecologists that are Lantra qualified tree climbers. Tree climbing using roped access is an advanced survey technique that allows us to climb-and-inspect trees to check for cavities and inspect them with an endoscope or mirrors. This has great advantages as it allows a detailed inspection of trees to be carried out cost effectively. Close inspection of tree cavities enables the surveyor to identify the presence of bats and evidence that may indicate previous occupancy by bats. It also allows the surveyor to assess the potential of a roost with greater confidence.

Due to the legal protection afforded to bat roosts it is important to minimise the risk of damaging or destroying a roost. If a tree roost is damaged, it is important that consultants and their clients are able to demonstrate that good practise was followed. At Baker Consultants we have a team of experienced bat ecologists that will be able to advise you on the appropriate level of assessment of the trees at your site. We can put together a survey programme based on your requirements.

Removal of trees as part of a planned development often requires mitigation and is likely to require trees to be recorded individually. Tree climbing is a cost-effective and efficient way to accurately record actual and likely bat roosts. We often work alongside arboriculturalists during tree works, climbing and inspecting the trees immediately prior to the trees being felled.

If you have trees on your development site that may need an assessment, contact Anton at a.kattan@bakerconsultants.co.uk.

Get our tree-climbers up there before they get leaves on (the trees that is)!