Definitions, data, and methods for primary forest assessment

This report has been prepared to review and assess definitions relating to primary forests; to collate and evaluate the datasets and methods currently available for measuring the extent of primary forests; and to provide options for defining, assessing and reporting on primary forests.

The Food and Agriculture Organization of the United Nations (FAO) Global Forest Resources Assessment (FRA) provides essential information for understanding the extent of the world’s forest resources, their condition, management and uses. Data collected through the FRA reporting process are used to assess progress towards globally agreed targets and inform policy and decisions by governments, civil society and the private sector. Therefore, concepts, definitions and methods developed for the FRA have broad influence beyond the FRA and must be carefully developed to ensure they can be implemented consistently by as many countries as possible, to provide comparable global information.

One such concept is the area of ‘primary forest’. The FRA requires countries and territories to report on the extent of their forests and defines several different types of forests for countries to report on. “Primary forest” is defined as “Naturally regenerated forest of native tree species, where there are no clearly visible indications of human activities and the ecological processes are not significantly disturbed”. Accurate and consistent global reporting on the extent of primary forests is crucial.

The FAO’s definition for primary forest has appeared in trade-related instruments, such as procurement policies and wood fuel regulations, and inconsistent reporting could lead to non-tariff trade barriers. In addition, accurate and consistent reporting is essential to assess progress towards global objectives such as the Aichi Biodiversity Target 5 forest-related goals and target proposed in the zero draft of the post-2020 Global Biodiversity Framework, Sustainable Development Goal 15 and the Global Forest Goals of the United Nations Strategic Plan for Forests 2017-2030.

While the definition of primary forest may be broadly accepted, consistently measuring the actual area of primary forest among countries has proven to be challenging. Studies have shown considerable variation in how countries apply the definition in their own circumstances, which raises questions about the comparability of the data among countries and its applicability for informing policy and decisions. In addition, other recent studies have suggested new methods to assess the area of primary forest, might be broadly applicable among many countries.

While the definition of primary forest may be broadly accepted, consistently measuring the actual area of primary forest among countries has proven to be challenging.

Although data collection efforts for the FRA 2020 have already been completed, the FAO’s newly established online data collection and reporting system will enable countries to update their data more frequently. As the FAO moves towards more frequent reporting to better meet the demands of other global reporting commitments, there is a pressing need to increase consistency in data collection requirements and schedules for primary forest in order to enhance comparability of forest statistics among countries.

Therefore, the FAO has aims to bring together national correspondents and other experts through a series of workshops to improve the operational methods for data collection and reporting on the extent of primary forests. The goal of these workshops is to increase the consistency of data collection requirements and schedules as well as enhancing the comparability among countries for estimates of the extent of primary forests.

Article authors

Dr Brendan Mackey

Brendan Mackey

Project Director and Director of the Griffith Climate Action Beacon at Griffith University, contributing to community planning and engagement in forest projects.
Pat Norman

Patrick Norman

Pat is a spatial research scientist focusing on the environment, forests and protected areas.

Additional authors

Dr Eloise Skinner


Mackey, B., Skinner, E., and Norman, P. (2021) A Review of Definitions,  Data, and Methods for Country-level Assessment and Reporting of Primary Forests: A Discussion Paper for the Food and Agriculture Organisation of the United Nations, Griffith University, Brisbane.

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