Modern pollen studies from coppiced woodlands and their implications for the detection of woodland management in Holocene pollen records

Investigations of pollen production, modern pollen-vegetation relationships and pollen-stratigraphic changes have been undertaken from three woodlands under coppice management to establish the impact that woodland management techniques (the periodic cutting of broadleaved trees and shrubs for wood and fodder) have on pollen representation. The number of inflorescences (catkins/flowers) produced over the length of a coppice rotation has been quantified for three species; Corylus avellana, Alnus glutinosa and Tilia cordata. For C. avellana the number inflorescences produced is significantly higher in the early years after coppicing. For A. glutinosa and particularly T. cordata flowering is suppressed after coppicing and only recovers slowly. In the later years the number of inflorescences produced by all three species is related to the height of the regrowths and therefore competition for light. However, the number of pollen grains produced per inflorescence appears not to be related to age in the coppice rotation. The modern pollen rain within the coppiced woodlands largely reflects differences in the vegetation of the coppiced areas rather than variations resulting from their age in the coppice rotation. High resolution pollen-stratigraphic records from small ponds record long-term vegetation trends, while the coppicing of adjacent areas is difficult to detect. Nevertheless, the results from these studies are broadly consistent with the pollen production investigations and together show that coppicing results in a shift in pollen production from canopy to under-storey species and may render some taxa (notably T. cordata) palynologically invisible. Model simulations, with corrections for differences in pollen production through the coppice rotation, have been produced for three types of basin; small ponds/hollows, small lakes and wet woodlands with A. glutinosa. These explore the impact of changes in the intensity and scale of coppicing on pollen assemblages from mixed deciduous woodland. The simulated assemblages are compared with mid-late Holocene pollen records from temperate regions of north-west Europe where archaeological/historical evidence suggests that woodland management is likely to have been practiced. Some changes in the representation of trees and shrubs recorded in pollen diagrams from small hollows within wooded landscapes in southern Scandinavia and from A. glutinosa woodland in southern England are consistent with woodlands being managed. Notably pollen diagrams from the northern Alpine Forelands and East Anglia are compatible with long-standing ideas that woodland was managed on a landscape scale during the Neolithic. Further studies are required to determine whether a number of related woodland management practices produce distinct pollen signatures and the impact of these processes on a wider range of species. (C) 2012 Elsevier B.V. All rights reserved.