Question
I have a willow tree planted 25 yrs ago at 25 mts away from the house.  It is planted on left hand side and back garden of the house.  Garden is 1mt. higher than house building.  Can tree the cause for house subsidence.  This is subsided on the front, about mts. away and right hand side.  I will appreciate your comments or advice.  

Many thanks.

Answer
That far away from the house there will not be any problems with the roots and the foundation. Willow tree have a fibrous root system and can cause problems with sewer pipes but the roots out at the edge of the tree dripline are not large enough to cause any foundation problems. A trees roots extend about 1 1/2 times the foliage area and these outer roots are the smaller roots on the tree. There should be no problem from the roots to the foundation.