Whats tree related subsidence/ heave?
Subsidence Trees take considerable amounts of water from the soil in spring and summer when they are growing most vigorously. Clay soils shrink when they are dried and expand when they become wetter. The combination of these two factors, particularly in extended dry periods can lead to subsidence in buildings near trees if their foundations do not go to a depth which the soil moisture content and volume remain stable. Heave Large, vigorously growing trees, particularly species with high water demands can dry soil to the extent that it does not re-hydrate completely in water. This can lead to the establishment of persistent moisture deficit, particularly where tree root deeply in the more impermeable soils, which are frequently the ones most prone to shrinkage and swelling. If such trees die or are removed the consequent re-hydration and swelling of the soil can lead to heave damage in buildings nearby, especially if they are appreciably younger than the tree/s (i.e. built on soil that
