Trees and Shrubs
The roots of trees and shrubs can affect footings by removing moisture from clay soils immediately underneath the building causing subsidence as the clay shrinks.
In its search for water, a tree root system can spread a lateral distance equal to the height of the tree. If in rows or grouped with other trees, the roots may spread up to twice the height of the tree.
Care should be taken when selecting trees and, as a guide, the trees listed should not be planted within the distance of their mature height from the house depending on the site classification and whether they are to be planted in a line or in a group.
Height of Tree(h) Distance from house (d)
d = 1 h for class H and M sites.
d = 1.5 h for class E sites.
d = 2 h for rows or groups of trees.
APPROXIMATE TREE HEIGHTS
| 10 to 20m | 20 to 30m | 30m to 60m |
| Acacias | But-But | Blue Gum |
| Ash | Cedars | Cypress |
| Athel Tree | English Oak | English Elm |
| Candlebark | Lemon Gum | Figs |
| Manna Gum | Palms | Karri |
| Pepper Tree | Planes | Pines |
| Willows | Sheoaks | Poplars |
| Yate | Silky Oak | River Gum |
| Yellow Gum | Spotted Gum | Sugar Gum |
