Irish National Forest Inventory. The second Irish NFI began in 2009 and was completed
in 2012 [30]. The NFI is a detailed survey of permanent forest sample plots with the purpose
of recording and assessing the extent and nature of Ireland’s forests in an accurate and
repeatable manner. Based on a national, randomised systematic 2 x 2 km grid sample design,
aerial photo interpretation of 17,423 grid points was carried out in 2006 and again in 2012. Following
ground checks, all potential forests plots meeting the national forest definition were
established as permanent sample plots. This is a modified approach of one of the most commonly
used NFI methodologies worldwide [59]. For the second NFI, 1827 permanent sample
plots were established. Based on the sampling design used, each forest plot (500 m2) is representative
of 400 ha of forest nationally. A suite of ground measurements are recorded at each
forest plot. Estimations of NFI forest cover estimates in the study areas were taken from the
results of the second NFI, for which field surveys were carried out in 2010–2012 [30]. All area
estimates are taken from the “Stocked Forest Area” statistics of the NFI.