Based on planting guidelines, it is generally not wise to plant a tree that has the capacity to grow to beyond 20 feet within 10 metres of a building.
Understanding the Guideline
The proximity of trees to buildings is a common concern due to potential issues like root damage to foundations, drains, and paving, as well as branches affecting roofs or walls. While a tree can physically grow very close to a building, the question often relates to what distance is considered safe or advisable to avoid future problems.
According to planting advice, specifically regarding larger trees:
- It is not wise to plant certain trees close to structures.
- The threshold mentioned is for trees that can grow beyond 20 feet in height.
- These larger trees should ideally be planted at least 10 metres away from a building.
This means that for trees expected to grow quite large (over 20 feet), a minimum distance of 10 metres (approximately 33 feet) is suggested as a wise planting choice.
Why Distance is Important: The Role of Roots
The primary reason for recommending a distance, especially for larger trees, is related to root growth. As highlighted in the reference:
- Tree roots require an equal blend of oxygen and water to thrive.
- Roots will colonize areas where these resources are available.
- Areas around buildings, especially foundations and drains, can sometimes offer favourable conditions (e.g., moisture from leaks or condensation).
The expansive nature of root systems seeking water and oxygen can potentially extend significantly outwards, sometimes equalling or exceeding the tree's height or canopy spread. Roots growing too close to structures may exert pressure, exacerbate existing cracks, or interfere with underground services like pipes. Giving the tree adequate space allows its root system to develop naturally away from the building's foundation.
Practical Considerations for Planting
When deciding how close to plant a tree, consider the following:
- Mature Size: Always research the potential mature height and spread (both canopy and roots) of the specific tree species. A small ornamental tree will have different requirements than a large oak or maple.
- Root Aggressiveness: Some tree species are known to have more aggressive or far-reaching root systems than others.
- Soil Type: Soil conditions can influence how roots grow.
- Drainage: Poor drainage near foundations can attract roots seeking water.
While the guideline specifically advises against planting trees over 20 feet within 10 metres, this implies that smaller trees might be suitable for planting closer. However, even smaller trees require space for healthy growth and to prevent minor issues like branches touching the building. Always err on the side of caution and consult local arborists or gardening experts for species-specific advice based on your property's conditions.
In summary, while a tree can grow physically closer, the wise and recommended minimum planting distance for trees capable of exceeding 20 feet in height is 10 metres from a building to mitigate risks associated with root development.
