This Chapter describes the planning and organisation of the terrestrial inventory and the interview survey. The criteria for the selection of personnel and equipment are also given, and the instruction, training and safety standards are explained. The preparation and implementation of the fourth Swiss National Forest Inventory (NFI4) drew on the information and experience obtained during the previous inventories (NFI1–NFI3). Changing the survey into a continuous inventory over 9 years (2009-2017) had consequences for planning and organising both NFI4’s field inventory and interview survey, and required redistributing the fieldwork over nine sub-grids. In the first three inventories (NFI1–NFI3), 10–12 field teams carried out the terrestrial survey over a period of 3 years, and the interview surveys were conducted immediately after completing the field surveys in each region. In NFI4, however, only three teams were involved in the terrestrial inventory which included the assessment of about 820 sample plots each year. The NFI4 interview surveys were carried out in two stages, in 2013/2014 and in 2017/2018,   also by field team members, but individually and no longer in pairs.