Fig. 4. Legacies and contingency.
Note: The ecological structure of the Ancient and Ornamental Woodlands in the New Forest National Park, UK, is in part the legacy of long-term effects of land use since AD 1200. The two curves represent the growth and decline of beech trees (Fagus sylvatica), plotted as percentages of beech pollen in total pollen sum observed in two peat basins (Church Moor and Barrow Moor) within the forest. Although the two curves show similar trends, the different timings for the rise of beech suggest that beech is a relatively recent species contingent on local conditions that vary over short distances. The horizontal lines show the duration of several important land-use practices, including using the forest for pasturing animals, coppicing and pollarding, timber extraction for local ship-building, and land drainage. The rise of beech in the 18th and 19th century is most likely a legacy of the decline in other tree species such as the oak used in ship-building. Declining trends during the 20th century are a result of the decline in traditional land-use practices coupled with greater vulnerability to wind-throw as the trees become taller and larger. Adapted from Grant and Edwards (2007).