The visibility of past trees and woodland: testing the value of insect remains

The reconstruction of woodland history is important in relation to archaeological, ecological, biogeographical and evolutionary problems, and insect remains are a significant source of relevant information. Fully natural interglacial and Holocene ‘waterlogged’ deposits assumed to have formed in woodland generally contain abundant macrofossils of both plants and insects indicative of trees. In contrast, British archaeological deposits rich in macrofossil remains of trees often lack, or contain very few, tree-associated insects. To cast light on this contradiction, assemblages of insect (Coleoptera and Hemiptera) remains from a range of modern deposits with various spatial relationships to woodland and trees have been analysed. The proportions of tree-associated insects varied greatly. There was a general trend from higher values in woodland and near to isolated trees of species supporting a rich insect fauna, to low or zero values where there were no trees. However, low values sometimes occurred in woods or near trees, so that rarity of tree-associated insects in archaeological deposits does not always carry the implication of a treeless environment. Further investigation is suggested, with emphasis on the importance of identifying isolated trees, scrub and hedges as a resource for humans and wildlife in the past.