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Re: RPA of Yew 19m high

Re: RPA of Yew 19m high
Posted by: chris (IP Logged)
Date: August 30, 2007 07:41

1) The RPA (root protection area) is an area of roots around a tree that needs protecting during development in order to ensure that the tree has sufficient rooting area to remain healthy. The important point here is that it is an area, measured in m2. It is not a linear distance.

Working out its size is based on the diameter of the tree at 1.5m, not at the base (except for multi-stemmed trees). For a yew of the size you have it is likely to be in the region of 250m2. This is equivalent to a circle of radius of around 9m, but a proper RPA is rarely circular.

2) No. An arboriculturist would assess where the RPA lay, taking in to account the area that the RPA needs to cover and the likely position of existing roots, based on what features exist on the site. For example, if the tree is next to a road it is unlikely that significant roots will exist under the road. So the RPA will not include the road, but will extend further in the other direction to compensate.

The arboriculturist should also assess the significance of the tree. They may conclude that the tree is a significant constraint on the development of the site, but others design the layout.

3) Planning decisions are not based on one factor. All the details have to be weighed up. Foundations within the RPA will generally harm the tree. If the tree is a grotty sickly looking thing and the application is for a much needed new hospital, then permission would probably be granted. If the tree is a fantastic, highly visible healthy specimen and the application is to extend a kitchen, then it probably wouldn't.

Of course, it also depends on how on the ball the particular council's planners are. Believe it or not, some pretty appalling decisions get made :)

All that can be said is that foundations within an RPA are certainly a consideration when reaching a decision, and would count against the development.

4) Cut it cleanly.

You've focused in your questions on the effect of the building on the tree. Don't forget the relationship works both ways. Yews cast dense shade all year round. Would you want a 19m one less than 5m from your home?

Subject Posted By Posted
|  RPA of Yew 19m high Flo 29/08/2007 19:19
||  Re: RPA of Yew 19m high chris 30/08/2007 07:41
|||  Re: RPA of Yew 19m high flo 06/09/2007 19:06
||||  Re: RPA of Yew 19m high chris 07/09/2007 12:30
|||||  Re: RPA of Yew 19m high roots 07/09/2007 12:43
||||||  Re: RPA of Yew 19m high mdvaden 21/09/2007 04:01

Advice offered in this forum is of a general nature only. It is by its nature not based on any site investigation and should not be relied upon. Neither the forum administrator nor any contributor will be held liable for damages occurring as a result of relying on advice given here. You should contact a competent arboriculturist for a more detailed answer.