weeping willow - again !

[annie tree]

thanks for all the advice so far, but having decided to buy the house and given that the tree is 7 metres from the house, (and on clay - of course!) I am told that cutting it down would cause more harm than good because of heave. what do you suggest - could we install root barriers ?

[RATTER15]

If you need to have the tree removed, call in a professional tree surgeon to do the job and ask for the roots to be removed, this is done with a root grinder and will not cause any damage to the surrounding are. Really you need to get the advice and even a written report from a professional tree surgeon to be on the safe side, then if there is any problems you have someone to fall back on.

[alan30]

How old is the house and how old is the tree? If the tree is older than the house and you are on a shrinkable clay soil then removing the tree could lead to heave. How big is the tree - the larger the tree the greater the water demand? I have removed mature oak from within 7m of a house after geotechnical investigations calculated the likelihood and extent of heave was negligible. Clay is a generic term for a wide range of soils and and there are many different characterisitcs within that range and not all are susceptible to shrink and heave depending on the water content. If you have soil date then an arboricultural consultant may give you guidance on the possibility of heave however you should bear in mind that this is an area of expertise for a structural engineer or geotechnical specialist.

[annie tree]

thanks alan30 - tree is approx 50 years and house approx 100 years. no signs of damage so far and we don't really want to cut it down at all if poss

[alan30]

With the differences in age heave is unlikely to be a problem. Root barriers are inherently unreliable and recent research indicates that heavy pruning even on a regular basis makes littel difference. Certainly the level of pruning required to make a difference is detrimental to the tree. Willlow on clay soil flags up warning bells but as I said earlier there are a lot of different clays and many mixtures of clay with flints and sands which can make a significant difference to the degree of volume change in a soil. On a rule of thunb you should be removing the willow. If you want to keep it you need to keep a careful eye out for cracking, particularly stepped cracking at the corners of doors or windows nearest the tree. If you want to keep the tree but don't want to take the risk then you need site investigations carried out. They will look for roots under foundations, a shrinkable clay soil and evidence of desiccation in the soil. Depending on where you are and the availability of the right experts the soil tests and root identification are going to cost upwards of �500. If you take advice from an arboricultural contractor make sure they are competent and insured to give the advice as this type of advice is more suited to an arboricultural consultant then contractor. A list of both is available on
www.trees.org.uk although there are plenty of others around not registered with this association.