Welcome to Part 2 of our latest guest blog post from Antony Wood of Yew Tree Gardens on Trees & Planning.
Let’s look at how trees may have to be considered in your building project. For all the benefits which we touched on in Part 1 there are places where problems start to occur with trees. Wouldn’t you just know it, the problems start appearing when people and structures (buildings) come into close proximity with trees. It is amazing how quickly all the positive benefits of trees are overwhelmed when paving starts to lift, leaves begin to accumulate in gutters and your dearly beloved can’t get to sleep on windy nights for fear of the 25m high tree in your neighbours garden appearing at the end of the bed. So how can all this be avoided, hopefully the answer is contained in a proper consideration of trees in the development process.
In order to reduce conflict with trees a British Standard 5837:2012 Trees in Relation to Design, Demolition and Construction was developed. We’ll now look at how this BS5837 standard is intended to fit into the development process to inform good design and construction in relation to trees.
How does BS5837 work?
Firstly, before going anywhere near the planning process, if there are trees on your site or immediately adjacent to it you will probably need a tree survey. A tree survey is conducted by an Arboriculturalist and will cover all the trees within the development site. If you are starting a planning application you will see a box to tick in answer to the question ‘are there any trees within or adjacent to the site boundaries?’. If the answer to this is ‘yes’ you may be asked by the Local Planning Authority (LPA) to provide a survey to BS5837:2012.
What happens next?
The survey and subsequent report is intended to identify the trees on site, their species, height, spread, condition, stem diameter and to use all these factors to assign a standardised retention category to the surveyed trees. The retention category identifies the likely retention span of the trees based upon a professional assessment of the tree and will identify trees which have everything from forty plus years to less than ten years of remaining contribution.
The information gathered in the survey along with judgements upon the assessed retention value of the trees is gathered together into a Tree Schedule. This schedule will also contain a calculated value for the Root Protection Area (RPA). The schedule is then used to plot the tree locations on a Tree Location Plan, ideally this is based upon an accurate site topographic survey but in any case will show the position of the trees, their canopy extents and a plot of the RPA. Additional information including estimated shadow plots from trees is also useful.
How is this information used?
All the above information should be fed into the design and layout of the development. This may require the design to be altered to accommodate trees but could equally identify that trees will have to be removed to allow development.
Once a definitive design and layout has been achieved it may be used to produce an Arboricultural Impact Assessment (AIA). The AIA will assess what impacts may be placed upon the development by retained trees and vice versa. It will also contain a Tree Constraints Plan (TCP) and suggested mitigation measures, including replanting for any trees which require removal.
The final stage of the process is the production of an Arboricultural Method Statement (AMS) and Tree Protection Plan (TPP). These are intended to identify any areas of specific working methods in relation to trees and a contain a detailed plan of the tree protecting measures on site. On larger development sites it may be a condition of the planning consent that tree protection measures are supervised and inspected by a site Arboriculturalist who will also supervise any works within the RPA of trees.
All the above is an ‘ideal’ outline of the workflow of BS5837. Your Arboriculturalist will be able to identify site specific issues and discuss options for solutions to any issues which might occur. This may involve input upon construction in RPA’s and being the interface with the LPA Tree Officer / Planners, your Architect / Designer and Structural Engineer.
Hopefully if all goes to plan you will achieve a completed development which has responded to tree constraints and results in positive contributions from the trees within your site bringing your project all the benefits of trees and none of the negatives.
Remember, there’s nothing worse than going to all the time and expense of designing your dream project only to realise that no one has considered the big tree in the middle of the site. It does happen!
Director | YewTree and Gardens
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