The arrival of mechanisation has meant more peat is being harvested over a wider area of bog and on a semi-commercial basis. Since the 15th Century traditional turbary has been responsible for the loss of 233,830ha of raised bog and 85,590ha of blanket bog. It is this change in how turbary is being practiced, coupled with the ever increasing demands placed on the bog habitat as a resource that has made turbary an urgent problem today. Major research has shown that peat extraction is having far reaching effects on bogs today. Peat cutting on raised bogs, even on the margins of the high bog can over time cause widespread drying out of the bog up to 500m from the face bank.
Drainage removes water and increases the dry matter content of the peat.
This causes shrinkage of the peat. The bog surface then slopes towards the cutting increasing the surface water gradient and therefore the rate of surface discharge. This process at Raheenmore caused a subsidence of 1.5m in the peat surface at the edge of the bog. Drains put in to dry out the bog in preparation for extraction have shown that bogs subside by as much as 5 to 6m depth alongside a drain and the effects of the subsidence are in evidence at a distance of 500m from the drain itself. Once the acrotelm disappears the bog is effectively no longer accumulating peat and has become moribund.