Large areas of Horsell Common have been designated as Sites of Special Scientific Interest (SSSI), and English Nature has commended the Common for its outstanding wildlife value. The open heathland areas form part of the Thames Basin Heaths Special Protection Area, under the terms of the European Birds Directive. The Common is of European importance for supporting breeding populations of three species: nightjar, woodlark and Dartford warbler.

The Society has a policy of active management to preserve a balanced woodland and heathland ecology and at the same time provide access to the public for open-air recreation and enjoyment. In 1999 a Site Management Plan for the SSSI's on the Common was drawn up together with English Nature. The plan outlines the active management that will be undertaken on the heathland areas including scrub clearance and grazing. Work is only undertaken outside the bird nesting season, which runs from April to the end of August.

Woking Rotaract assist with the preservation of the common by removing scrub, mainly small birch and pines, from areas of heathland. It is very rewarding work and good fun too and it give us the opportunity to meet other volunteers who are interested in assisting the local community.