Scientists at the University of Newcastle, UK, are using DNA fingerprinting to help insurers identify trees that are causing houses to subside.

Often disputes can last for several years, as when two trees of the same kind grow in an area it is very difficult to find out which one is behind the problem. This is because their roots which can grow underneath a house and cause the subsidence may stretch for several metres in different directions.

The scientists have set up a company, Bioprofiles Ltd, to carry out the work. It is believed to be the first company in the UK to offer this service. It will be working for aboriculturalists tree specialists - and building surveyors, as well as insurance companies.

Kirsten Wolff, one of the company's directors, explained how it works:

"Houses built on clay are particularly at risk from subsidence, and more so in times of drought. Tree roots suck water out of the ground, which causes the clay supporting the house to dry out and contract.

"We would typically get involved in a dispute over which tree is responsible for the subsidence, especially when both the householder and his or her neighbour own trees which are equally likely to have roots spreading under the subsiding house. We try to establish which tree is to blame and thus indicate which insurance company should pay out.

"The problem is much easier to solve when there are different trees growing in the area. It's easy to tell the difference between an oak tree root and chestnut tree root, for example. It's when you are faced with trees of the same kind in the same vicinity that the scientists have to step in."

Dr Wolff, Reader in Evolutionary Genetics at Newcastle University's School of Biology, and fellow scientist and company director Dr Marie Hale, begin their work by taking samples from th
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Contact: Kirsten Wolff
Kirsten.Wolff@ncl.ac.uk
44-0-191-222-5626
University of Newcastle upon Tyne
27-Aug-2002