 Insight into the global forest resources assessment process. Forests cover nearly one third of the land on Earth. They shelter most of the planet's irreplaceable biodiversity, help fight climate change and are a source of fresh water, timber and many other vital products and services to humankind. Reliable information on the status of the world's forest resources and their ongoing trends is crucial to halting deforestation and managing forests wisely to preserve their functions. The Food and Agriculture Organization of the United Nations, known as FAO, published the first survey on the forest resources of the world in 1948 at the request of its member states. This survey was followed by a series of more comprehensive assessments that are now produced every five years under known as Global Forest Resources Assessments, or FRA. The results of these assessments have been used for many purposes, from assessing the availability of timber for post-war reconstruction to developing policies to fight tropical deforestation and the alarming associated loss of biodiversity. Today, FRA is the most comprehensive assessment of the world's forests, including their management and uses. It is also the only global assessment that is based on official national statistics. FRA data are widely used to support evidence-based recommendations by governments, civil society and the private sector and to inform international conventions and agendas. In particular, FRA plays a central part in monitoring progress towards sustainable development goal 15, life on land. But how does the FRA process work? While the earliest assessments were mainly conducted by FAO experts, the more recent ones are based on data provided directly by countries. These data are reported to FAO by national correspondents, national experts officially nominated by the countries to coordinate compilation of data from different national sources. The National Correspondent Network covers 187 countries and territories, which together contain 99.5% of the world's forests. FAO trains the national correspondents on how to compile country reports using commonly agreed terms and definitions and a standardized reporting methodology. This is crucial for consistent reporting across countries. Moreover, designated FAO experts support the national correspondents throughout the reporting process and help them to solve any issues. The actual reporting is facilitated by a dedicated online platform, which also gives the national correspondents access to external data sources, such as the latest satellite images and other geospatial data. But FRA is not only about numbers. National correspondents are also asked to thoroughly document all the data sources they have used to make country reports as transparent and complete as possible. When a report has been submitted, the FRA secretariat and external experts review the content to ensure that data are complete and consistent, and that common reporting methodology has been correctly applied. Country reports are then sent to the highest forest authority of each country, the head of forestry, for their final approval. Once published, the approved data are used to analyze the status and trends of global forest resources. The results of the assessments are offered to the public in a number of formats, including a global report, individual country reports, an online open access database, scientific papers and other summary outputs, all important to form a comprehensive picture of the world's forests.