Ireland's National Forest Inventory (NFI)

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.

Between 2004 and 2006 the Forest Service carried out the first NFI, with results published in 2007. The 2006 NFI was the first purely statistical approach to forest inventory undertaken in Ireland to provide an assessment of growing stock in both the public and private national forest estates. The fieldwork for the second cycle of the NFI began in 2009 and was completed in 2012. Data collection for the third NFI began in 2015 and was completed in 2017.

On all occasions multi-resource information was recorded including information on forest area and species composition, growing stock volume, biodiversity, health, and carbon content; for the entire national forest estate.

In order to assess changes in the state of Ireland’s forests over time, Ireland’s NFI was designed using permanent sample plots which facilitated repeated measurements. This robust reporting strategy was adopted to provide credible information to address strategic objectives and reporting commitments. Repeated NFI cycles have provided results on aspects such as forest area change, volume increment and latest felling volume estimates.