Root protection cordons.

[samwise]

Hi, just wondering if anyone can give me a chapter and verse on when and what diameter a root exclusion zone should be, and what, if any, ground work is permitted in said zone?

Cheers.

[Amelanchier]

A root protection area (RPA) as described by BS5837:2005 is 12 times the diameter of the stem at a height of 1.5m. (or 10 times the diameter just above the basal flare of a multistemmed tree).

 

Similar guidance is offered by NJUG Vol 4 guidelines. Which breaks the root area into zones.

 

I've attached the NJUG guidelines below - they're freely available to download from the NJUG website. The British Standard on the other hand, is a different matter.

 

Has the RPA/zoning been specified for planning reasons or utility work???

NJUG VOL 4.pdf

[arnoldbuchsassinger]

More 11 times than 10 if we get our BS5837 head on, and nothing can go inside that zone, a great big barrier should be put up, no building materials can be deposited on roots inside, no waste materials can be emtied inside, it is an exclusion zone for a reason. Depending on the location of the tree you can slew the RPA by 20%, however you need to look at how the tree has grown, ie in an open area where its roots will probably just fanout in all directions, or in a wooded area where there are lighting issues and dominance issues.

[Amelanchier]

More 11 times than 10 if we get our BS5837 head on, and nothing can go inside that zone, a great big barrier should be put up, no building materials can be deposited on roots inside, no waste materials can be emtied inside, it is an exclusion zone for a reason. Depending on the location of the tree you can slew the RPA by 20%, however you need to look at how the tree has grown, ie in an open area where its roots will probably just fanout in all directions, or in a wooded area where there are lighting issues and dominance issues.

 

11? Where'd you get that from???

 

You right that you may offset the RPA of an open grown tree by up to 20% in accordance with BS5837:2005 but there is no provision for offsetting a NJUG zone. That's because one is a planning tool and the other a mitigation guideline.

 

I interpret 'open' as meaning there was nothing to impede the growth of the tree above or below ground. That includes other trees!

[Johny Walker]

drip line springs to mind or has it changed AGAIN ?

[samwise]

i used the dripline as a rough guide, but have now amended, the link on Tony's first post is crystal clear. cheers guys.

[Paul Barton]

Maybe I haven't been around long enough - was the drip line ever the recommended root protection area?

 

Bear in mind BS5837 was written in 2005 so what Tony points out above has been the accepted norm for 4 years or so now.