This may be a stupid question...

[Amelanchier]

In answer to the original question. Not a fact!

 

I can see the reasoning of the TO, with regard to Shigo's concept of root to shoot ratio. i.e., the tree strives to maintain a (near) equilibrium between roots and shoots.

 

However this refers to fibrous / feeding roots which are unlikley to be the ones responsible for the displacement of the wall. The displacement, if I understand the situation correctly, is due to the annual incremental growth of the structural roots of the tree. And if the tree is close to the wall - the annual growth of the root collar / flare.

 

Imagine the implications for tree stability if a 25% reduction resulted in a similar percentage loss of structural roots!!!

[Zenfordinner]

A study was undertaken by university of Cambridge (east malling research) called "controlling water use of trees to alleviate subsidence risk" (horticulture LINK project 212).

The final report, May 2004) is interesting and may be of some use to you.

[Amelanchier]

Indeed, interseting stuff and is referenced in the doc posted in another thread -

 

http://www.oca-arb.co.uk/pub/journal_of_building_appraisal.pdf

 

However, not really anything to do with the direct action of displacement of a wall by incremental growth.

[silvafox]

Thanks TS. I need to get some more literature. When quizzed by the client about the TO's statement I was shy to agree as it did'nt seem quite so black and white to me. Seemed a bit 'arboriculture by numbers' to me.

I did however rcommend the tree should be removed as its an overgrown weed in a bloody stupid place and causing hazard and damage to boot!