What is a 1,000 years old, 16.26 m high, 28 m wide and has just been voted European of the year?
A giant Holm Oak tree in the north of Spain, that’s what. Trees are marvellous things, the ultimate triumph of Nature’s plants. They provide shade in the summer, shelter from the rain and are always pleasing to the eye.
Trees And Building Problems
However, sometimes they don’t mix well with the building environment. Often planted much too close to buildings, as a small shrub they don’t do much harm, but the roots, finer than a human hair initially, will grow and swell and penetrate brickwork allowing in water to penetrate into the foundations and creating instability.
Even more important, and often more noticeable, is that they can penetrate and crack piping, eventually 
blocking it and causing leakage. That leakage can cause a great stink and undermine foundations again, sometimes going unnoticed for many months or even years, until subsidence cracking is noticed in terraces, pools, walls and plasterwork.
Even irrigation of these trees causes problems with the walls being continually dampened and that eventually penetrating, to spoil the decoration and give rise to mould internally.
In the southern coastal areas of Spain, the tallest tree is often the eucalyptus, which spreads its seeds readily, and can grow to a substantial specimen almost unnoticed. They survive the long hot summer due to their drought resistant properties, but these properties include a great spread of water seeking roots, within the top half metre of soil, which can remove moisture required for other plants and leave a semi-desert underneath the eucalyptus tree. More harmful to the buildings, is that they can swiftly dry out supporting soils, especially clay, which shrinkage again can gives rise to lack of support for the structural elements of the building.
Tips For Planting Trees Near Buildings
The general rule of thumb is that any tree should be planted more than 2/3 of its eventual height away from a building, with more being allowed with clay soils.
Much better to think ahead and hope for a 1,000 year old tree, rather than one that has to be chopped down in the first 20 years of its life.
