Damage to Infrastructure by Tree Roots.

Arguably the single largest myth affecting Tree professionals, is the misconception with regards the extent of damage caused by tree roots. It is a misconception that has also entered the archaeological / heritage sector, with much blame levied at past plantations being planted too close to archaeological remains.

Little research actually exists, (proportionate to the huge quantity of variables to be considered) and whilst there is in existence many ‘guidelines’ these fall well short of actually being useful at all and certainly should not be used by the insurance industry or others as definitive.

In reality the situation on the ground is far worse and the myths with regards tree root damage are culpable of a huge amount of wrongful insurance decisions, unnecessary tree removal and also the spreading of a fear towards trees which is now widespread throughout suburban UK.

In my experience both in the UK and in France, (there is a huge difference in practice between the 2 countries), I have never come across a situation where a tree root is directly responsible for damage to a built structure. I have seen many examples where the lack of necessary and often legally obliged maintenance to structures has resulted in providing a niche in which tree seeds have been able to propagate. I have also come across many examples where the soil profile left in a garden or plot for landscaping following construction work is dangerous in itself and thus subsidence and other problems occur, which would have occurred without landscaping and planting, yet the latter receive the blame.

The hard truth is that tree professionals, (and they are professionals unlike many who feel they can contradict or ignore their advice), are left to pick up the pieces and yet should have been involved from the outset of planning and even with regards architectural design.

There is also at play a huge missing link in the processes of development in the UK. Further to the above the abuse of soils during construction is endemic and as unsustainable as it can get, even on so called sustainable development projects. It has reached a stage where you will simply not find a site where the soils have been remediated as they should be subsequent to development. Indeed you can hold the UK up as an example of using phytoremediation and bioremediation practices at all times – this is by default – the result of efforts by a poorly paid landscaper or forester who has no budget to do anything more than plant and hope for the best and in a bizarre paradox; the trees, which are ultimately blamed for future problems were actually the one factor that helped to alleviate that problem for many years previously. The ‘Landscape Architecture’ industry has done much to lessen such problems but without real governance and legal framework to deal with the issues, the costs involved shun good practice in favour of cheap practice.

The Arboricultural Association are amongst one of the best accreditation organisations in the UK , but despite the best of efforts in tackling poor journalism and general misconceptions by larger industries this is a battle little recognised beyond the arboricultural and forestry industry itself.

We continue to see the placing of untrue facts via the media into the public domain. At present many of these untruths are criticisms of now historic Forestry Commission practice. Archaeology, for which the UK has an obsession for, has been placed high up in the list of issues in relation to Multi Functional Forestry. I am not in disagreement with this, but some commentary on damage to archaeological sites by plantation forestry is somewhat overzealous. I know for a fact that many sites in the areas I used to work in in Argyll, the archaeological features were simply not even known about prior to initial surveys by Foresters.

A wee digression: In Kintyre and Knapdale, a forestry contractor used to construct forest tracks had an understandable urge when discovering large rocks to up end the rock and leave a monument, which looked identical to many of the standing stones in the further landscape. It was a form of signature of his work. In one location he discovered several such rocks and the temptation to create a stone circle was too much. The subsequent report following the archaeological survey, (as part of the Environmental Assessment required for all large new plantations), a considerable chunk of proposed planting area was removed to create a buffer zone around the historic monument, constructed just a month previously.

I have been to archaeological sites, which have subsequently been identified as having been damaged by roots, but there is absolutely no way this could have been possible, the distance needed to be covered by the tree roots was simply too far. I am sure there are locations where there has been damage, but they are rarer than the general public are being led to believe. The only times I have witnessed damage to sites of historic importance by tree roots it is as a result of natural regeneration of native trees.

Is the protection afforded by the ‘strimmed grass’ land management regime found at many Englishh Heritage sites any worse than the weed infested open ground of an historic site found within a forest plantation? I have always been disheartened when visiting English Heritage sites to discover that from Neolithic time, through to WWII a strimmed finish is the fashion, a misinterpretation which could easily confuse most people. It is a real shame that a taste of the land management of the period of time when these sites were in use cannot be displayed and maintained.

I would not advocate the French system, where the destruction caused by invasive species such as Robinia pseudoacacia, Fraxinus angustifolia or Ailanthus altissima  remains largely unchecked and worse used as an example of ‘urban biodiversity’ benefit. There is a common ground between the UK and France and it would be easy to implement guidelines based on this.

Is the power of the insurance lobby simply too big to fight, is there simply too much money at risk here?

The current and ongoing UK situation however is bordering on criminal: Once in Devon, I had to investigate a case when an insurance company had refused to pay out with regards the subsidence of a garage; claiming an apple trees roots has caused the damage – the apple tree in question was more than 10metres from the garage, less than 10 years old and its roots had not even spread beyond a metre from its stem!

As a continuing theme in my blogs, I am referring back to the UK forestry panel, whose remit will apparently cover all trees and woodland in the UK. One hopes that certainly in regard to new planting, the constant message from the Arboricultural Association, Tree Council amongst others will be incorporated into policy and measures to ensure ongoing maintenance and the implementation of good practice as identified by these bodies and the forestry and arboricultural industry at large will become a fixed standard. But with the quoted prices of tree planting and retention that are currently being offered as incentives, particularly with regards carbon offsetting projects, it is impossible to believe that everyone has yet understood these concerns and that there will still be a huge amount of tree planting to occur in the UK, without any budget for future and essential maintenance both to protect the trees and also infrastructure.

Heywood Castle, Heywood Forest, Eggesford Devon

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1 Comment

Filed under Trees and Woodlands

One response to “Damage to Infrastructure by Tree Roots.

  1. Setlist

    Just came across your very interesting blog and wanted to comment on this entry in particular. Firstly, what a beautiful blogsite! I fundamentally believe that trees and woodlands contribute to the wellbeing of the human condition – call it a soul, call it a spirit, call it just plain awareness of the world we live in – and am lucky to live in a heavily urbanised area where I can look out of my back window and see a surprising number of large, lovely specimens (I frankly don’t care if they’re sycamores or ornamentals – some peopel seem to get a bit precious about the “wrong” sort of tree, but a 70ft sycamore is a magnificent sight!).

    Secondly, in a former life I worked for a number of years as the conservation planner for a metropolitan authority and part of that role involved dealing with the making, confirming and managing of tree preservation orders. I think it’s the one part of my professional career that I have been most proud of, despite the constant low-level (and in one or two memorable cases, not so low-level) aggression and disgruntlement demonstrated against the tree officers and me by both developers and, more often, members of the public when we thwarted plans to take down perfectly healthy and harmless specimens. How dare we? Didn’t we know these were their trees and we had no right to intervene? Well, actually that tree has been there 100+ years and if left alone will be there for another 150, and you’ll be in that house for, oh, about 7 years or something, so it isn’t really YOUR tree, now, is it? Sorry, digression /rant over; what I wanted to say was that I came across the same argument you have outlined in your post so many times it became a personal trigger. No, trees don’t “invade your drains and break them” – like any living thing, they will seek water and when they find a broken or leaking drain, then they will move in. Yes, if you’d employ a better builder who was capable of building proper foundations to cater for the roots of a distant tree, then you won’t have a problem down the line. And no, Mr Insurance Company Man, we don’t really agree with your arboricultural hired guns’s report about what’s causing the subsidence. It grieves me terribly when I see our friendly TV property experts slagging off trees and the damage they cause when you only have to look at the state of some of the houses they’re filming to know there’s been no maintenance or remedial work undertaken for many years, so you would expect there to be problems. You know who you are.

    And don’t get me started on the developers who rip out trees and hedges without fear or favour prior to getting planning permission and then complain at the costs involved in planting semi-mature trees and having to maintain them for a few years. Hmmm, try working with the landscape next time, dolts. Oh, sorry – that would involve things like imagination and design and layout skills your company simply doesn’t possess. Easier to just start with a blank sheet of A1, isn’t it?

    I’m delighted to find this blog and will return!

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