Several threatened forest species are currently associated with semi-open, wood-pasture conditions and do not thrive in present-day, non-intervention temperate forests of north-western Europe. We assess the changing importance through time of five disturbance agencies that open forest canopies and induce the past structure of these forests. The influence of browsing and grazing animals has varied through time, but was most intense from domestic animals during recent centuries. The role of large ungulates on forest structure during the early Holocene was negligible. Fires of both natural and anthropogenic origin have been of importance in the past, but have now virtually ceased. Past effects of waterlogging have been severely reduced by drainage schemes. Windthrow has been a relatively constant factor through time, while anthropogenic influence has dominated forest structure, particularly during recent centuries. Natural forest structure is probably more open and varied than found in present-day, non-intervention, reference forests, due to variable combinations of these disturbance agencies.

Summary Fossil records of Cannabiaceae pollen and Cannabis achenes from Flandrian deposits at three sites in eastern England are presented as further evidence for the past cultivation of this crop. It is suggested that retting of hemp to extract fibre was carried out at each of the sites.

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Succession after fire has mainly been studied by chronosequence, which does not allow study of pre- and post-fire communities at the same site. By using palynology and anthracology, we recovered vegetation communities and fire histories through time on islands of Duparquet Lake, Canada. We show that succession after fire is dependent on interval between two fires (evaluated with depth of humus between subsequent fires). Sites with high fire occurrence show a cyclic succession (same species reappearing after fire), while sites with low fire occurrence show a directional succession. Different fire intervals lead to different pre- and post-fire pollen assemblages. During longer fire intervals, pollen assemblages change from Pinus banksiana Lamb. domination to Pinus strobus L. and Picea mariana (Mill.) BSP domination. When fire intervals are short, Pinus banksiana dominates both pre- and post-fire assemblages.