Evidence of former tree growth at Clonsast

Abstract

Six thousand years ago practically all the ground now covered by peat in the area investigated at Clonsast, County Offaly, was woodland. The main object of the research was to trace the disappearance of woodland due to peat formation; and to investigate the subsequent sporadic colonisation of the bog surface by new trees. By means of pollen analysis and the identification of macroscopic remains from the peat the changes in vegetational cover which took place down to the present day were traced. Pollen diagrams from four sites in the bog and an analysis of seeds and other macroscopic material from one of these sites are presented. The oldest peat examined was formed just at the late-Boreal to Atlantic transition. In addition, the woody remains found had to be identified and a section of the thesis is devoted to this problem. Photomicrographs illustrating points by which timbers were identified are included, as is also a brief section on charcoal identification. Further sections comment on the possibility of applying dendrochronolcgical methods to bog timbers, and on the difficulties involved in the afforestation of peatlands. The thesis is presented in two parts - Part 1, Text,and Part 2, Diagrams.