This system was originally devised as a means of achieving logical decisions in the planning and management of woodlands and urban tree populations, by assessing the relative contribution of different trees and woodlands to the visual quality of the landscape. It was not devised as a means of attributing values to trees for compensation or for the calculation of appropriate fines, but it has been used for these additional purposes in numerous instances. It should be noted that the valuation of trees for amenity purposes can never be a totally precise exercise, and this booklet should be regarded as a guide rather than a precision instrument.
The methods described in this publication are based on proposals which were first published in the Arboricultural Journal (Helliwell 1967). The method of evaluating individual trees was subsequently adopted, in a slightly modified form, by the Tree Council and published as a leaflet in 1974. This leaflet was reprinted and updated by the Arboricultural Association in 1984. A slightly modified version of the evaluation methods for woodlands was also published as a leaflet by the Association in 1986.
This revised edition of the Helliwell System, co-published by the Tree Council and the Arboricultural Association, has seen further changes made in the light of experience and comments received. The Arboricultural Association has in recent years organised workshops on the use of this System under the guidance of Rodney Helliwell and Steve Coombes. This has provided additional feedback, which has been helpful in guiding the adjustments that have been made from time to time.