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Primary woodlands are of scientific interest for the study of natural population dynamics and of conservation interest because of their formerly widespread distribution in Europe. Field recognition of primary woodland based on the present vegetation alone can be difficult, and no system for recognition of such sites has been established in Ireland. Many Connemara lake islands support dense, low woodlands that have been proposed to be representative of Irish ancient woodland. Thick mor humus layers occur on these islands which form a contrast with the treeless mainland covered by blanket peat. Pollen analysis of the humus layers from two islands of different size revealed that the present woodland was about 300 years old, and both islands were cleared of trees before that time. An earlier phase of more diverse woodland on the larger island pre-dated the clearance. Several woody taxa colonized the islands after the clearance episode, and Taxus baccata L. was an early dominat in the absence of grasing. Quercus petraea (Mattuschka) Liebl. became established on the larger island, but failed to dominate, and Ilex aquifolium L. became the most abundant species, both as mature trees and as seedlings. Pollen analysis of mor humus is an ideal method for establishing the recent history of an individual woodland, and also for examining successional relationshjips between woody taxa that cannot be easily ascertained from studies of contemporary woodland.