Anthropogenic Changes From Neolithic Through Medieval Times

Abstract

SUMMARYThe long period covered by this paper probably saw the most drastic changes wrought by man on the plant cover of these islands in the whole of postglacial history. Much of our information about vegetation changes comes from those parts of the country where peats and mires are abundant, which leaves those areas which were the cradle of successive cultural groups largely unrepresented. Sources of environmental evidence are now emerging even from this unpromising background, an important element amongst which are man's own works. The evidence of changes wrought by man may come from non-botanical as well as botanical material. Pollen, charcoal, phytoliths, seeds, mosses, and other macroscopic plant remains may be extracted, but indirect evidence may also be obtained from land snails, insects, bones (including small vertebrates), as well as from preserved soils and land surfaces.In the various environments considered a trend from forest through clearance to pastoral or arable agriculture can usually be demonstrated. These changes may ultimately result in site deterioration on a large scale, the nature of which will depend upon the ecological conditions and the practices at work. In extreme cases peat may form or soil erosion take place. On base-poor soils, soil acidification may become so intense that the land is no longer usable for traditional agriculture and is allowed to degenerate to moorland or heath. In early historic times much degraded land came into use again for hill-grazing, a process which further depauperated both the flora and the soils.

Tilia Cordata Miller

“…It seems to have been an important source of fibre from prehistoric times (Clark 1952;Ashbee 1963;Dimbleby 1984), at least until the cultivation of hemp in the Middle Ages, and the practice was widespread in Europe (Retzius 1806;Hanssen & Lundestad 1932;Hedemann 1939;Granlund 1943-44). Bast was obtained from young poles and therefore from coppice.…”

The recent vegetational history of the Forest of Bowland, Lancashire, UK

“…These population levels are comparable with those of England during the fourteenth century. Thus the woodland landscape would also almost certainly have been extensively exploited for materials needed for domestic use, such as housing and fuel; Dimbleby (1984) suggests that coppiced woodlands, consisting of Corylus trees, lnay have been encouraged for villa building. Persistent Compositae pollen and Pteridiiitn aquilinum spores at this time in the Bowland profiles are consistent with widespread vegetational disturbance, although Tinsley & Smith (1974) suggest that Plantago may be a better indicator of regional landscape disturbances.…”

Short-term, post-burial change in a humic rendzina soil, Overton Down Experimental Earthwork, Wiltshire, England

“…A number of sites fit this pattern. For example, at Silbury Hill, Wiltshire, all traces of the original soil structure have been lost through immense compression induced by some 30 m of overburden, and only 3% void space remains (Dimbleby, 1984;Macphail et al, 1987). In contrast, the buried calcareous soil beneath a chalky Neolithic barrow a t Easton Down, Wiltshire, shows few signs of transformation into a massive soil (Macphail, 19931. The results from the present study highlight both the speed with which compaction and structural change can occur after burial, and the way in which the nature and extent of structural modification varies according to local environmental conditions and associated pedogenic changes.…”

“…Only in exceptional circumstances is plant material preserved on downland archaeological sites, for example, the excellent preservation of mosses and grasses under extreme anaerobic conditions beneath Silbury Hill (Dimbleby, 1984). Usually the only traces of plant material that survive are the result of either ferruginization (see below) or the formation of calcium carbonate root pseudomorphs (Courty et al, 1989).…”