Forest history is one of the bases by which biodiversity in woodlands can be explained. In practice, forest history is mainly investigated in relation to research about ancient woodlands, or to particular scientific questions. However, it seems necessary to assess forest history not only for specific occasions but to take it as a base for an evaluation of the naturalness of any particular forest. Naturalness is a widely used criterion for evaluating the current state of a forest in relation to specific nature conservation values. It refers to the actual composition of the vegetation, neglecting any historical processes. To assess naturalness within a dynamic concept means to display a set of criteria that reflect the individual historical development of a forest. This has to include certain key processes, such as the continuity of woodland existence, the process of regeneration, competition, ageing and dying, but also a set of criteria characterizing the human interference during all the reconstructable past. © CAB International 2004.