UKTC Archive

Re: RPA offset for ploughing

Subject: Re: RPA offset for ploughing
From: Jerry Ross
Date: Aug 12 2019 10:14:44
Certainly it can be justified under the right circumstances: it may well be reasonable to offset an RPA if the adjacent land has been deeply cultivated, as there may not be (m)any roots left there. But you'd need to have some insight into how it had been ploughed: how deeply, how regularly and also how recently. Cultivation opens up and aerates the soil, so regular, fairly light ploughing (say to no more than 20-30cm) carried out over many years may just mean that tree roots have migrated further down, to below ploughing depth where they carry on more or less regardless. On the other hand, even relatively light ploughing of virgin land will tend to take out a higher proportion of significant roots, simply because they are likely to have been shallower. Deeper ploughing, to 50cm or more, has over recent years become more frequent simply because the advent of tractors the sizes (and prices) of small houses means that operators can slice through roots without even noticing them. Old, long-established trees are particularly vulnerable as while they may have survived quite happily in and around cultivated fields simply because older tractors would have been forced to work around them; hence the proliferation of stag-headed oaks in cultivated fields. On the other hand, more recently still, no-till or shallow-tillage techniques are becoming more widespread, which should work to the benefit of trees.

So you need to make a judgement as to whether what's gone on historically means that it's now reasonable to consider that land as been lost to the treesand so can be taken out of a root protection area. You also need to look at whatever is being proposed for the land: if tree roots are simply a bit deeper because of cultivation, will the development being proposed go deeper and still do damage?

On 12/08/2019 10:19, AV Arboriculture wrote:
Has anyone ever come across instances of reducing a tree's root protection 
area because of ploughing activity? If so, have they been justified, or can 
it be justified?

Mike Charkow

Arbor Vitae Arboriculture Ltd

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