Old-growth forest inventory areas of Koillismaa and northeastern Kainuu (data-sets 1,3 and 6) - Selection of study sites

First 10 x 10 km squares, delimited by gridlines of the finnish national uniform grid system (Grid 27 E; Heikinheimo & Raatikainen 1981) were randomly selected in the study area (municipalities considered in the data-set). The same squares were used, if possible, for data-sets 1, 2 and 3 in Koillismaa, and for data-sets 5 and 6) in Kainuu. Of each selected 10 x 10 km square, all such 1 x 1 km squares (limited by gridlines) that fullfilled the sampling frame criteria (that is, that they consisted of an old-growth forest inventory area and were either above or below high-altitude area limit) were listed. Among these squares one was randomly selected to be a study quadrate.

If no 1 x 1 km square totally fullfilled the criteria, the 1 x 1 km square with the highest coverage of suitable area was selected. The minimum recuirement was that at least 2/3 of the square area had to fullfill the sampling frame criteria.

If a suitable study quadrate was still not found, the surroundings of the 10 x 10 km square was considered. The 1 x 1 square that was closest to the centre of the original 10 x 10 km square and had at least 2/3 coverage of the suitable area was selected.

If no suitable study quadrate was found in the radius of 15 kilometres, the 10 x 10 km square was abandoned and a new one was randomly selected.