Established trees are wonderful in our living spaces; they provide shade from our hot summer sun, privacy screening from our neighbours and attract birds into our lives. All efforts should be made to protect our established trees, but when it comes to construction, some realism must prevail.
Some clients want to build close to established trees, and while this is often possible, an understanding of the implications of doing this need to be made clear from the start.
Root systems of trees pull nutrients from, and exchange carbon dioxide & oxygen through the surrounding soil. The following construction activities can have an impact on tree health:
- Heavy machinery operating close to the trees can compact the soil
- Cutting through main roots
- Piling up dirt around the base of the tree to grade the land
Over 5 to 10 years trees that are damaged by construction can start to die. Some mitigating strategies are:
- change the plans to build further from the tree (how far will depend on the type of building & tree type)
- have the tree removed (see below note about under-story protection before making this decision)
- ensure heavy machinery does not come close to the tree or its root system
- do not grade around trees (possibly using protective material around the tree base)
If you must build close to established trees, consider the impacts of this decision – long-term destruction of the tree or, if you want to continue to build near the tree (& save it from damage), extra costs from possibly not using heavy machinery.
If the tree is damaged beyond repair, consider leaving the tree in place to protect the under-story and grow new trees in its place while the old one deteriorates. Removing a tree later, rather than sooner is not necessarily more difficult.
Like all building projects some degree of compromise may be necessary to save these beautiful organisms that bring so much to our living environment, and having an understanding of the considerations before starting will help you to make an informed decision.
Bringing an arborist to the site during the planning phase would be the best option so that any decisions can be made from a position of expert knowledge.