Lichens are increasingly used as indicators of the ancientness of native woodlands, and for the biodiversity and conservation assessment of woodlands. National and regional Indices of Ecological Continuity have been used for such purposes for nearly 30 years, but have never before been brought together in a single publication, and some have existed only in the 'grey literature'. For each Index, this guide provides instruction on their usage and applicability, as well as listings of the lichen species involved.