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tree consultant arboricultural consultant
tree expert witness
Trees in relation to development.
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Introduction:
There are many reasons why you may wish to carry out work close to trees, some common examples are to:
add an extension;
add a conservatory;
lay new, or replace service trenches;
build one or more houses;
construct new roads or driveways.
If you would like to discuss your project, give me a call.
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General Comments: If you want to carry out any construction work close to trees growing on your property, or on a neighbouring property, you will almost certainly have to prove to the Local Authority prior to obtaining planning permission, that your actions will not harm any significant trees that are worthy of retention. Local Authorities typically ask for an Impact Assessment Report to be included as part of your planning application. These reports should be produced by a suitably experienced tree consultant, arboricultural consultant.
Some allied professionals are not aware of the importance of trees on development sites, and it is not uncommon for site design layouts to be produced which do not take trees into consideration. Be aware that if a design is produced in such a way, it may have to be modified, or even scrapped, if the Local Authority decides that some important trees must be retained.
It is critical to note that if you do not provide adequate information to the Local Authority, they may decide to refuse your application or they may conclude that the trees are at potential risk, and protect them with a Preservation Order.
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British Standard 5837 (September 2005)
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British Standard 5837 is the industry standard, and nationally accepted document, for providing recommendations in relation to the juxtaposition of trees and buildings. The British Standard now forms the basis for all arboricultural impact assessments relating to development sites. It was revised and updated in September 2005. The British Standard recommends that all implication assessments should be carried out by a tree consultant, arboricultural consultant.
In an attempt to identify which trees are worthy of retention, the British Standard suggests a category rating for all trees growing on proposed development sites. Four broad categories have been identified within the British Standard, and guidance notes have been included to assist in the assessment of trees. The correct assessment of trees is vital, as it may be that some trees are not worthy of retention, whereas others may have such high visual amenity to the locality, that their retention will be essential. The first picture below shows a British Standard 5837 category "A" Sycamore tree. The second picture shows a British Standard 5837 category "B" Silver Birch tree.
 One of the most fundamental changes in the new category rating system, as opposed to the 1991 edition, has been the recognition that trees with a safe life expectancy in the region of ten years or less, would be category "R" rated, and that trees with life expectancies of between 10 and 20 years (i.e. between category "R" and category "B"), should be classified as category "C". British Standard 5837 recognises that category "R" trees should be removed, whilst category "C" trees should not normally be retained where they would pose a significant constraint on the development of a site.
The retention, or removal, of category "C" trees can sometimes be contentious, as Local Authorities invariably wish to retain as many trees on a site as possible. Although the retention of category "C" trees is laudable, there are many circumstances where their removal is both sensible, and reasonable, due to other site related factors. Even though your trees may have a category "C" rating, it does not necessarily mean that the Local Authority will let you have them removed. A qualified tree consultant, arboricultural consultant, will be capable of identifying trees worthy of retention on a site.
The current edition of British Standard 5837 contains a new system of assessing the safe distance between trees and buildings. The assessment is based on tree trunk diameter, and is the basis of calculating a "Root Protection Area". In the majority of cases no excavations will be allowed within Root Protection Areas, although this can occur in certain instances. If you need to carry out some construction within the Root Protection Area of trees, please give me a call, and discuss your options.
Once the Root Protection Areas for the trees have been calculated, you will need to have a plan produced, known as a "Tree Constraints Plan". This should be used as the basis for the production of your design layout. Remember, that if at all possible you should not attempt to do any excavations within the Root Protection Areas of any trees that are to be retained. Your architect will use the tree constraints plan to enable him to identify the optimum position for any construction excavations.
 The British Standard acknowledges that it is possible to carry out construction within the Root Protection Areas of trees, i.e. if the foundations are constructed on engineered designed piles. The following three pictures show that piles can be inserted using small percussion devices, without the necessity for large mechanical equipment. The first picture shows the piling on a site where no trees are close-by. If trees were a constraint on the site, the ground beam would be at ground level, not in the ground as the second picture depicts.
 In addition to the concept of a "Root Protection Area", the British Standard provides increased detailed guidance and recommendations relating to the physical protection of trees, prior to, and during, the development of a site. You will need to submit a "Tree Protection Plan" with you planning application, showing how you intend to protect any retained trees. The positioning of the tree protection will be based on the root protection areas of the trees.
As mentioned earlier, one of the common reasons for working near trees is the siting of new roads or paths. If the construction is within the Root Protection Areas, then the Local Authority will almost certainly request that a "No-Dig" method of construction be used. The most appropriate way of constructing a no-dig road or path is usually to use a Cellular Confinement System, such as produced by "Terram". I can provide guidance and recommendations for the construction of unadopted roadways and paths, and provide names of companies that supply appropriate materials.
In some instances the design of developments can be complex, and the local authority may ask for a "Method Statement" to be produced, which will provide instructions on carrying out specific tree-related operations. I often produce method statements for clients.
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