SUMMARYThe results of palaeoecological analyses and lithostratigraphic investigations are used to reconstruct the Flandrian evolution of a valley in the East Sussex Weald, the Brede. Particular emphasis is placed upon mid-Fiandrian vegetational history. Palynological data collected from one site, Brede Bridge, include detailed resolution of declines in Ulmus and Tilia pollen. Predominantly inorganic sediments were deposited in the valley during the early Flandrian. Marine conditions penetrated the lower valley under the general influence of sea level rise. After c. 6000 DP, peat formation hecame widespread and ^/wws-dominated communities occupied the valley floor. Despite forest clearance on the adjacent slopes, relatively little sediment was deposited in the period c. 3700 to c. 1800 BP. The lower \ alley again came under a marme influence after c. 1800 BP. The dryland forests of the valley were, during the mid-Flandrian, dominated by Tilia. A general upward decline in Tilia pollen through the sequence is attributed to the valley floor widening and the Brede Bridge site becoming more distant from dryland areas. The first signs of human activity accompany the Ulmus decline, though major forest clearance is not evident until the Tilia decline c. 3700 BP. Comparison of the latter event with sites across south-eastern and southern England offers support for a phase of human expansion in the late NeoHthic/early Bronze Age involving the preferential exploitation of areas of lime forest.