There is no denying that trees are a beneficial asset to the environment, our lifestyle and are a symbol of a healthy landscape. They create shade and privacy, contribute to better air quality, provide habitats for wildlife, and help to reduce salinity and soil erosion.
However, without proper consideration and monitoring, trees can also impact our built environment by causing damage to buildings, paths, driveways, and underground infrastructure.
A tree’s influence starts, literally, at the roots; they are responsible for keeping the tree alive by drawing essential nutrients and water from its surroundings. The roots will continue to grow as a tree matures and during this growth, the roots will extend towards anything that will maintain the tree’s life. Roots typically seek out moist soil and will often find entry into old or damaged pipes including sewer drains, sewer pipes and water mains. If a tree is removed from the soil, the foundation will be displaced due to the tree root no longer absorbing water, which could damage a building.
Seasonal change also influences how trees interact with the built environment. During the warmer months of spring and summer, soils can dry out with the lack of moisture causing reactive clays to shrink. In extreme cases, shrinking soil can lead to significant ground movement, subsidence and foundation settlement across the home. Unfortunately, trees can exacerbate this process. In their hunt for moisture, root systems will extend through dried soil, desiccating the ground and absorbing remaining water from the already dry soil. According to insurance company LV, subsidence claims have increased by 49% in the last year, although the rise is in part due to an increase in building surveys, but dry weather in the summer has largely contributed to the spike in claims.
There can be a risk of tree roots causing subsidence. The combination of dry soil and thirsty tree roots is the perfect recipe for ground movement, and the appearance of worrying subsidence symptoms, including cracks in brick walls, distorted timber frames, and doors and windows that jam. Examples of different causes of subsidence around the home, including those triggered by tree roots, can be viewed on Mainmark’s interactive house. Understanding the cause of problems is essential before a viable solution can be found.