Tree root horror stories–most of us have heard one. Trees breaking into pipes, drains, lifting house foundations, cracking paving and splitting open house walls. It does happen when trees that are very aggressive growers have been positioned poorly in a suburban environment without consideration to the possible consequences.
This doesn't mean that you should miss out on growing trees in your front yard and backyard though; instead, careful forethought will ensure that the trees you do plant will not cause any root problems.
1Understand what happens with tree roots. The roots of trees keep the tree in place and are like hoses, seeking water for sustaining the tree through absorption. Tree roots are encouraged by:
- Leaks in pipes and sewers: Here is an easy source of water to access!
- Cracks in pipes: Tree roots aren't capable of cracking pipes. Rather, tree roots seek water and if there is a crack, the root will enter via any crack and start increasing inside the pipe as the crack widens under the pressure, until there is a blockage caused by the roots.
- Surface of the soil: Most moisture and nutrients sit at the surface of the soil; hence, tree roots will form at the surface to take advantage of this. If it is a large and vigorous species of tree, this surface growth can crack pavement, pavers, etc.
2Be considerate about where you plant trees. Siting the tree properly from the outset makes good sense. This even includes trying to think about future building on your site should this be something you might want to do down the track. Things to consider include:
- Finding out where draining and water lines are and planting trees well away from these.
- Avoiding planting trees that you know will grow too large. Ask your local municipality if it can recommend which species of trees to avoid planting. See "Tips" for some of the more common problem trees.
3Know the general rule. Knowing where to avoid placing trees requires knowing how big the tree's roots will grow. The general rule is that trees produce roots equal to about three-quarters of the tree's mature height. This means a tree 20 meters (65.6 ft) high will have roots of 15 meters (49.2 ft).
4Find smaller trees if you don't have the space. You don't have to miss out on shade and greenery. Instead, prefer smaller tree species. At the same time, ensure that your plumbing is in good order and replace broken and cracked pipes as soon as you are aware of them.
- Problem trees include: willow trees, bamboo, cedars, English oak, Jacaranda, Norfolk Island pine, pine trees (these also "gutter-clutter"), poplars, camphor laurels, fig trees, several large gum trees, and rubber plants. This list is by no means exhaustive.
- Drought and clay soils are often the cause of cracks rather than trees. During a dry period, the tree roots extract water from the clay soil, speeding up its drying out. The soil shrinks and anything built over it can crack as it settles. Movement occurs again when there is moisture returned to the soil, as it expands. This problem is less likely on sandy soils.
Things You'll Need
- Knowledge of trees that are OK to plant and not OK to plant
- Knowledge of final mature height of trees you wish to plant
- Measuring tape