Trees and planning constraints
There are three kinds of planning constraint affecting trees:
1. Conservation Areas give the local authority control over works to trees, as well as demolition of buildings and some building alterations.
2. Tree Preservation Orders (TPOs) are typically applied to trees, singly or collectively, which are thought to be under threat. A summary conviction for contravening a TPO results a fine of up to £20K.
3. Trees may be protected by a condition placed on a planning consent.
For trees in a Conservation Area or subject to a TPO, consent for tree works has to be sought at least six weeks in advance. Proposals have to be justified. It is not always strictly necessary to apply for consent (as when a tree is dead or dangerous), but it is best whatever the circumstances in case the local authority think that the proposed works are not in fact necessary.
Summary of Example Report
The sycamore tree in the front garden is subject to a Tree Preservation Order (T.P.O.). Its roots have pushed the garden's north and west boundary/retaining walls outward, lessening support over time for the north and west end of the house. This is the probable cause of cracks in the west elevation.
Two other factors may have contributed to this process: (i) a defective water main, disrupted by the tree’s roots and replaced around 1995, which could have led to some erosion of the soil near the north-west corner of the house, and (ii) the recent construction of a neighbouring driveway on the north (lower) side of the north boundary. In addition, the root system of the tree is highly eccentric (constrained on two sides by the difference in level), resulting in many large roots adjacent to and under the west part of the house. These are so big that they could have contributed (over time) to the development of stress concentrations at the base of the house.
Remediation involves the rebuilding of the front-garden boundary/retaining walls, and this work cannot be completed without the removal of the tree, which has overgrown the boundary. Thus a case can be made for felling the tree and grinding out the stump. Any work to a tree subject to a T.P.O. requires the prior approval of the local district council.