The purpose of the National Forest Inventory (NFI) is to record and assess the extent and nature of Ireland’s forests, both public and private, in a timely, accurate and reproducible manner. Reliable, current and consistent information is required to inform domestic forest policy, to support forest research and fulfil national and international reporting commitments. The NFI is a detailed periodic survey of permanent forest sample plots based on a randomised systematic grid sample design. A grid density of 2km x 2km provides enough forest plots to achieve a national estimate of volume with a precision of +/- 5%, at the 95% confidence level. This grid density equates to 17,423 points nationally, each representing approximately 400 ha. Each circular NFI sample plot measures 25.24 metres (m) in diameter, comprising 500 m², and is permanent in nature to allow future re-sampling on them.