Trees Distances

WHERE TREES SHOULD BE PLANTED – A Balanced View.

Very little root action leading to subsidence damage to buildings in the UK is caused by direct physical pressure exerted by roots. A tree has to be very close to the structure indeed for such damage to occur. Planting a tree so close to a structure that trunk buttressing or increase in trunk diameter was being restricted could lead to damage. More commonly, pavements and boundary walls with little or no foundation may be lifted by large shallow roots of, for example, Populus, poplar, species. Buildings with adequate foundations, standing some distance from trees, are very rarely subject to such direct damage.
Most reported damage is secondary in nature. The problem is confined largely to soil types that shrink considerably on drying. In the UK these are mainly certain types of clay and some peaty, fen soils. Under conditions of drought when tree roots remove water from shrinkable soils, they accelerate the drying and shrinking process. This can lead to loss of support to inadequate foundations and subsequent subsidence. Continued drought, even in the absence of trees, can lead to subsidence in such circumstances.
Tree root spread data have most relevance to relatively ‘safe’ planting distances when relating to trees growing on shrinkable clay soils. Planting distances on other soil types that do not contract on drying have to be determined more by consideration of the respective scale of the buildings and trees, the ultimate size of the trees, and the desirable or undesirable qualities of the trees concerned. In all cases it is wise to consult a qualified expert.

KEEPING A SENSIBLE DISTANCE

Table below shows the Minimum Distance from property and Maximum root spread recorded

Cypress Cupressus  Min – 3.5 metres  Max – 20.0 metres
Cypress Chamaecyparis Min – 3.5 metres Max – 20.0 metres
Birch Betula Min – 4.0 metres Max – 10.0 metres
Apple Malus Min – 5.0 metres Max – 10.0 metres
Pair Pyrus Min – 5.0 metres Max – 10.0 metres
Cherry, Plum and Peach Prunus Min – 6.0 metres Max – 11.0 metres
Hawthorn Crataegus Min – 7.0 metres Max – 11.5 metres
Rowan & Mountain Ash Sorbus Min – 7.0 metres Max – 11.0 metres
Plane Platanus Min – 7.5 metres Max – 15.0 metres
Lime Tilia Min – 8.0 metres Max – 20.0 metres
Black-Locust Robinia Min – 8.5 metres Max – 12.4 metres
Beech Fagus Min – 9.0 metres Max – 15.0 metres
Ash Fraxinus Min – 10.0 metres Max – 21.0 metres
Horse Chestnut Aesculus Min – 10.0 metres Max – 23.0 metres
Elm Ulmus Min – 12.0 metres Max – 25.0 metres
Maple & Sycamore Acer Min – 12.0 metres Max – 20.0 metres
Oak Quercus Min – 18.0 metres Max – 30.0 metres
Willow Salix Min – 18.0 metres Max – 40.0 metres
Poplar Populus Min – 20.0 metres Max – 30.0 metres

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