Root Barriers

[MRH64]

I have a TPO to fell and replace a dying Cypress, not such an issue except the adjacent land is being considered for build of a garage and the potential root spread for a fully grown Cypress would likely inhibit this. However a potential solution is for a root barrier to be placed between the proposed garage and 3 meters from the replacement "Sapling". This distance is within that for a mature Cypress, but for a growing one I do not anticipate it would cause any issues?

I would appreciate any  thoughts and advice on this, especially if there has been any similar work linked to TPOs.

Kind regards

MRH64

[Steve Bullman]

bump

[daltontrees]

too many unkowns to attempt an answer. Cypress, what species? Location and soils, esp shrinkable clays? Why 3 metres? And I'm not sure I understand the question.

[JonnyRFT]

NHBC guidelines should consider the ultimate height of the tree and its zone of influence. The foundations of the garage to be constructed should be to the required specification based on the above-mentioned factors. If the root barrier is solid and linear to protect the garage, you may run the risk of roots girdling somewhere between 2-3m within one quadrant of the root plate. For a mature tree, it would be like having a wine glass with just under half of its base missing. Personally, Id allow the roots to deflect around the garage foundations. If the foundations are deep enough, then there should be no significant movement of the building, even in shrinkable soils. 

 

 

Edited Friday at 21:21 by JonnyRFT
Spelling

[MRH64]

Hello Jonny, thanks very much for your comments, most welcome. Having reflected on this perhaps it's obvious that the side of the proposed garage that faces the new sapling, if placed within the potential root spread of the Cypress when it becomes mature (in say 30 years), would in effect act the same as a commercially available root barrier. How limiting this would be in reality to the welfare of the tree depends of course on the proximity of one to the other and the depth of the garage foundations. My belief, please tell me if I'm incorrect, is that over the time that a sapling grows into a mature tree, it would be much more tolerant and accommodating of a barrier that is located say 1 metre off the perimeter of the known root spread for a Cypress (I think this is circa 5 meters), than for the case where a barrier is similarly located but fir a pre-existing mature tree.

To try to put this more succinctly, placing foundations 4 metres out from a newly planted sapling Cypress will probably have no affect on its welfare, even if the guidelines state 5 metres for root spread, as these are written to prevent damage to roots of mature trees.

I suspect is all a matter of degree, hence the simplest thing is to apply the guideline irrespective of the age of the tree, but I wondered if anyone had any experience of this rule being applied less stringently when a sapling is being planted, particularly in this case to replace a TPO tree.

[monkeybusiness]

Root protection areas can (and should!) be drawn to include physical barriers to roots. What you are proposing sounds sensible to me - a root barrier on one side 3m from a newly planted tree should have minimal/zero effect on its long term growth and stability (assuming the rest of the rooting area is unimpeded and of suitable material). The tree will ultimately grow to its environment. 
If in the future you wish to build on the other side of the root barrier the RPA should be drawn to include the root barrier, and the arboricultural method statement would include this detail as mitigation for what might otherwise be considered incursion into the RPA. 

Edited Saturday at 08:57 by monkeybusiness