In 2019, it is 100 years ago since the first National Forest Inventory (NFI) was established in Norway. The establishment of the NFI in 1919 was motivated by a fear of over-exploitation of timber resources. Just a few years later – in the 1920’s – similar monitoring programs were to follow in Finland, Sweden and the USA. Later, debates on acid rain in the 1980’s were a trigger for initiating NFI’s in central Europe. In the recent years, climate change (REDD+) has triggered the establishment of new NFI’s, especially in developing countries while most developed countries now have regular NFI programs.