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Tree Surveys FAQs

Tree Surveys FAQs

The following are a range of Frequently Asked Questions relating to tree surveys:

What is BS 5837? Produced by the British Standards Institute, this Standard defines what input an Arboricultural Consultant should have in a planning application where trees are involved. It dictates what information should be gathered in the tree survey and makes recommendations about the impact that various construction activities may have on trees.

What are Retention Categories? These are defined within BS 5837 and relate to the size, quality, life expectancy and amenity value of each tree. There are 4 categories as itemised below:

CATEGORY A - These are generally large, high quality trees which the local authority will want to see retained if at all possible.

CATEGORY B - These may be somewhat smaller or not particularly high quality trees. However, they still make a significant impact on the local environment and have a significant life expectancy. The local authority would prefer to see these trees retained, though the removal of occasional specimens may be acceptable.

CATEGORY C - These are smaller trees or ones considered to be of low quality. They may have a limited life expectancy or contribute very little to the amenity of the locality. Such trees should not be considered as a constraint against development and their removal will generally be acceptable.

CATEGORY R - These trees are recommended for removal due to their poor condition rather than to facilitate development.

What is a Root Protection Area? This is the area around each tree which should contain enough roots to sustain the canopy. During a tree survey, the surveyor will measure the diameter of each tree stem. For straight-forward, single-stemmed trees in a uniform environment, the Root Protection Area (RPA) is equivalent to a circle with a radius equal to 12 x stem-diameter. This means that for a tree with a diameter of 50cm, you should try to avoid disturbing the ground within 6m of the tree stem.

Unfortunately, trees rarely grow in a uniform environment. An arboricultural consultant should amend the shape of the RPA to better suit the site conditions. For example, a tree growing adjacent to a road will have few roots under the road and will require the RPA extending further in the opposite direction.

Do I have to completely avoid all works in RPAs? Avoiding disturbance to the RPA will the preferred option of the local authority tree officer, since this guarantees no significant impact on tree health. However, sometimes it is necessary to develop within RPAs and special construction methods need to be employed to minimise impacting on tree roots. Crown Arboricultural Consultants are experts in advising which works are likely to be acceptable to the local authority and which ones are likely to lead to a planning refusal.

How should I choose an Arboricultural Consultant? An arboricultural consultant may play a pivotal role in determining whether an application is successful, so you should choose carefully. Here are some things to look for:

EXPERIENCE. You should choose a tree surveys/arboricultural consultant with several years of experience working with BS 5837, both as a private consultant and as a local authority tree officer. Ideally, your tree surveys consultant should have a good understanding of construction principals and experience in the construction industry.

QUALIFICATION. Your tree surveys consultant should have at least a Level 5 qualification in arboriculture and should be a member of related professional organisations.

INSURANCE. Adequate Professional Indemnity Cover should be carried.

REPUTATION. You should choose a consultant who has a good reputation amongst local authorities as well as with discerning clients.

HIGH STANDARDS. Sub-standard tree surveys or reports will fail to meet validation criteria.

VALUE FOR MONEY. The cheapest tree surveys service does not always provide the best value for money. A failed application can be very costly and a good arboricultural consultant will help you to achieve the maximum potential from your site.

A good arboricultural consultant will be happy to provide proof of the above.