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.
The
cache-
Is not in the bog and can be reached with
out leaving the road .
No fences need to be crossed to find the
cache.
Please replace exactly as found to avoid
the cache being found by muggles.