The need for tree work will sometimes become self-evident to tree owners and site managers in the course of their regular duties. In many circumstances, however, there will be a need for systematic surveys and inspections to be conducted by competent persons, including where appropriate external experts with skills in areas such as the recognition and interpretation of the origin and significance of symptoms caused by damage or physiological stress.
Generally, trees develop in balance with their environment both above and below ground. Conflicts with people and property can, however, result from natural processes of growth and dieback or from the effects of damage caused by severe weather, pests or diseases. Equally, human activities can lead to conflicts, if these activities affect the growth or structural integrity of trees, or increase or adversely modify their exposure to the wind by the removal of other trees or the demolition or construction of buildings.