Open Structured Woodland and the Ecological Interpretation of Scotland's Ancient Woodland Inventory

Abstract

Following intensive human land use over millennia, European forest ecosystems record among the largest values of deforestation globally. This puts a premium on European ancient woodland, which has existed in the landscape minimally over several centuries. Ancient woodland in the UK was quantified in the Ancient Woodland Inventory (AWI). In cross-checking AWI sites in Scotland, it came to our attention that a proportion of 'Class 3' woodlands, which are thought to be of recent origin (regenerated since the nineteenth century), retain scattered tree symbols. This paper quantifies the degree to which Class 3 AWI sites may correspond to areas of scattered trees or open growth woodland. We show that a significant number (c. 50%) of Class 3 sites appear to have continuity of tree/woodland habitat; this may be particularly important for interpreting the distribution of ecological guilds such as tree-dependent epiphytic lichens and invertebrates. The study serves to re-emphasise that (i) technological limits and priorities of map makers, (ii) value systems of historical geographers, and (iii) biology of species, should be carefully considered and aligned during ecological research, so that potential anomalies, for example, the continuous existence of open structured woodland, can be fully recognised during application of systems such as the AWI.