Building regulations do not apply to trees and hedges but foundations can be affected by tree roots and soil moisture.
Such matters should be considered when planting/removing trees or building new structures as certain tree species can affect foundations over 20 metres away.
Disclaimer - Wales
This is an introductory guide and is not a definitive source of legal information. This guidance relates to the planning regime for Wales. Policy in England may differ. If in doubt contact your Local Planning Authority.