Which tree survey do I need ?

Sycamore canopy in spring bud

Clients are often asked by planners or others for a tree survey, but are not always sure what type is needed.   We have outlined the different types of tree surveys and the reasons they are needed.

A. Development survey = BS5837:2012 ‘Trees in relation to design, demolition and construction- Recommendations’

A Development Survey also called BS5837 survey is the one normally required by Local Planning Authorities (LPA) for development and planning permission.

A competent “arboriculturalist” [ = tree person ] must inspect the trees on and adjacent to the site. The trees on site are assessed in terms of their retention value which includes their health, longevity and amenity impact.

Trees that are marked for retention, as well as any adjacent trees not on site but affected by development need to be protected from any potential harm that may occur during the demolition and construction phases of the project. This involves both above and below ground precautions. Above ground, the crown spread and dimensions of the tree will need protecting, below ground the roots of the tree are a constraint governed by the Root Protection Area (RPA).

( The RPA is the area the tree’s roots occupy – this requires fencing and ground cover to protect it from above ground operations.) Information on protective measures for the trees on site will be provided as part of the BS5837 report.

B. Tree Hazard Surveys

Where you are concerned about your “duty of care” over a tree, then a Tree Hazard Survey is the one you require.

All tree owners have a legal responsibility as their “duty of care” to ensure others are not at risk from falling trees and branches. You need to assess the level of risk involved on your land. The risk is generally assessed based on :

  1. The level, extent and type of access that people have to the land on which the tree stands or where the branches could fall.
  2. The condition and health of the tree.

The factors underlying the condition and health of the tree will dictate how often the tree should be re-inspected for potential hazards. Advice on mitigating hazards by undertaking tree work can be suggested as part of the inspection, which you need to act upon.

C: Advice on Tree Works

Tree works on trees in Conservation Areas or on those with Tree Protection Orders on them need a “Tree Works” application.

When carrying out any tree work it is always advised that a competent arborist be consulted, whether it is a consultant or a tree surgeon. Work should be carried out in line with the British Standard, BS3998:2010 ‘Tree Work- Recommendations’. Trees should be inspected before the work is carried out too ensure the best management practices are employed.

Trees in Conservation Areas and with TPOs often have high amenity value and are well loved by their owners, so are felt to be worth the extra investment.

D: Surveys for underground utility installations

As stated in NJUG Guidelines for the Planning, Installation and Maintenance of Utility Apparatus in Proximity to Trees, there are generally low incidence of damage to underground apparatus by trees where these installed within hard surfaces ( e.g. pavements ). However trees can have variable growing patterns in term of root structure, especially if there are below ground obstructions to root growth. This can make any changes on site in the trees RPA potentially hazardous. Work on operational land for utilities often requires no LPA application, however it is considered good practice to follow BS3857 to implement tree protection methods where possible.

What is a BS5837 tree survey?

In April 2012 the revised BS 5837: 2012 ‘Trees in relation to design, demolition and construction – Recommendations’ came into practice. The British Standard provides guidance in respect of trees on development sites.

When conducting the tree survey onsite the arboriculturalist will make decisions on which trees are to be retained by looking at the condition of the tree and the potential is has grow and develop healthily. Useful questions to ask as part of a tree inspection are: does the tree have any structural defects? Is it significantly contributing to the amenity of the area? Are there any signs of early disease? What is the estimated remaining lifespan of the tree?

Information will also be collected on the spatial dimensions of the tree such as stem diameter, height and crown spread. The tree survey data can then be used to inform design stages and establish methods for tree protection during the demolition and construction phases of the project based on which trees are marked for retention.

If trees are to be retained, constraints to be considered are both above and below ground. The root protection area (RPA) is the constraint below ground, this is the area in which the tree has established its root network and must be protected throughout development. The constraints above ground are dictated by the height and spread of the tree, future growth potential, shading potential and what you are proposing to construct. This applies to planning applications for most developments.

If the work you are proposing does not involve Local Planning Authority (LPA) consent it is advised that surveys be carried out as described in BS5837 to inform good design practice.

If your trees are subject to Tree Preservation Orders (TPOs), or are within a conservation area the legislation that covers protected trees overrides any permitted development rights. Work carried out without consent from the LPA can lead to prosecution.