Up until the 1970s, the State policy in Ireland was largely to grow forests to rotation lengths of maximum mean annual increment. With increased demand for timber in the late 1970s, the Irish Forest Service, issued operational guidance to shorten the rotation lengths of some of the key forest commercial species to increase supply. For supply and market reasons, it has been customary in Ireland to adhere to rotations of maximum annual volume production, with rotation lengths shortened by between 20% and 30%. However, this should not be taken as a mandatory prescription for rotation lengths as other site factors are taken into account, including the land owners objectives. Deviating from rotation lengths can happen for a variety of reasons. These can include the felling of trees that have not grown successfully, or early felling of stands that are susceptible to blowing down. Considerations such as landscape, conservation and seed potential may also determine the length of rotation. Coillte is examining their estate and their strategic vision will see changes to how the estate is managed which will improve carbon stocks.
It is important to note that irrespective of the length of rotation all harvesting and felling is subject to the Forestry Act 2014. My Department can attach specific licensing conditions, in addition to good forest practice, to take into consideration a sites particular circumstances and limit any significant impacts on biodiversity and water quality. It is correct to say that growing trees for longer time periods can increase the carbon stock in forests. However a balance needs to struck between all the different functions a forest can provide such as timber, carbon and biodiversity.
