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Garry BogAntrim
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Summary Full report
Site Type: Altitude: 50m, Inland exposure
Site Status: ASSI
Grid Reference: C9429
Rock Age: Quaternary (Holocene)
Other interest: tephra, Interglacial deposit, raised bog, grassland, temperate forest, tundra

Summary of site:

Garry Bog, immediately beyond the northern outskirts of Ballymoney, is the largest area of lowland raised bog in Northern Ireland. It is a site of seminal and supreme international importance in the development of dendrochronology and the pioneering site of tephrochronology in Ireland.

Dendrochronology is the science of dating trees by the counting and measuring of annual growth rings and offers a means of establishing (by compiling overlapping series from many trees) real dates for events extending back up to 10,000 years before the present time. A related science is dendroclimatology, in which the pattern of tree ring growth is used to establish climatic trends. Over many years farmers have used this large exposed area for cattle grazing and have been in the habit of dredging the remains of well preserved trees out of the bog and heaping them into massive wind breaks to offer the livestock some winter respite. It is these tree remains, largely oak and pine, that have provided the raw materials for the dendrochronologists. The oaks from the bog established long time series that provided the framework of a standard known as the Belfast Long Chronology, used to calibrate radiocarbon dates (which are not exact) to real dates. This work was conducted in Queen’s University Belfast, establishing for it a pre-eminent international position in this field. Garry Bog oaks also featured in an international radiocarbon laboratory comparison exercise. It was also at Queen’s University that the link between the oak and pine dendrochronologies was established, allowing real dates to be applied to pines for the first time. This research has had a wide application in the study of pine timbers in England. Tephrochronology is the study of fine tephra - dust fragments resulting from explosive volcanic activity, carried high into the atmosphere, that fall everywhere downwind. When they fall into accumulating and dateable deposits, such as sediments, polar snowfields or, as in the case of Garry Bog, on to the growing bog surface, there is the potential to date the volcanic events that created them. The Garry Bog has proved to be the finest record in the British Isles of volcanic activity in Iceland since the last phase of the ice age. The tephra are found in well-defined layers that formed soon after the eruptions; they have also proved to be excellent marker horizons in pollen studies. The bog remains of paramount importance in continuing studies of early environments and has provided an interesting background for international prehistoric events linked to climate change. Its survival is consequently of the highest national and international importance. Damage to the bog has resulted from marginal turf cutting and drainage to ‘improve’ its agricultural and forestry value. The blocking of existing drains to restore and retain the water table should be undertaken to maintain the rich Sphagnum moss flora in active growth. Future management plans should restore a more natural woodland after the harvesting of the present tree crop.

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