The development of Ireland's tree cover over the millennia.

  • Fraser Mitchell Botany Department, Trinity College, Dublin 2.
Keywords: Forest cover, climate history, biodiversity, hazel, pine, elm, oak, human impact.


Ireland is not only the least wooded country in Europe, it also has the lowest forest biodiversity. Despite this, forest research repeatedly demonstrates that Ireland is one of the most favourable locations for growing trees in Europe. Augustine Henry was acutely aware of these issues which provided a stimulus for his promotion of Irish forestry. Yet Irish forests have not always suffered such paucity. The further back we go in time, the greater the forest cover and diversity we discover. This paper traces the decline of Irish forests over many millennia and addresses the principal causes of this decline. Global climate change, human exploitation and geographical isolation are all contributory factors. The repeated glacial-interglacial cycle of climate change over the last two million years has decimated tree diversity in north-west Europe. The degree of Ireland 's isolation from Europe has varied as sea levels have changed in tandem with global ice volume. This has influenced tree migration rates and direction but the Irish Sea should be considered as a filter rather than a barrier to tree migration. Recent analysis of a large fossil pollen database is used to illustrate the migration of forest trees into Ireland following the most recent deglaciation. These migration models are compared to newly emerging genetic data on European and Irish oak diversity. Human exploitation of Irish forests over several millennia has radically reduced the amount of forest cover and has significantly impacted on what remains. Reconstructions of forest composition are used to place contemporary Irish forests in context. This context is relevant both to the maintenance of existing forests and the establishment of new ones.
How to Cite
Mitchell, F. (2000) “The development of Ireland’s tree cover over the millennia.”, Irish Forestry. Available at: (Accessed: 2February2023).
Forest Perspectives