Fig 1. Characteristics of the stands comprising the study area.

Distribution of the forest stands included in the study classified into present development stages (x axis) and site types (bar fill). The development stages and site types were defined in the forest inventories conducted by the Finnish Forest Centre. ‘Young’ stands have a mean diameter at breast height of 8–16 cm, and ‘Mature’ stands a mean diameter at breast height greater than 16 cm but are not yet ready for final harvest. ‘Ready for harvest’ stands are greater than 16 or 14 m in dominant height and at least greater than 70 or 90 years in age, as defined in the current Finnish recommendations for the timing of final felling [35]. Site types are presented according to the Finnish forest classification system [36] and range from fertile mixed-species stands (herb rich) to less fertile, pine-dominated stands (dry heath).