Roots of hazel trees
 

I have a small garden and planted a hazel about eight years ago. I keep it
cut fairly heavily to a height and width of approx. 9-10 feet. The tree is
watered very well obviously especially during the hotter months but due to
the fact that the mains drains run about 5-6 feet away from the trunks
themselves I am worried that the roots will still search vigorously for
water and pose a threat to the stability of the drains.

Any comments would be greatly appreciated.