Assessing Forest Naturalness

The concept of naturalness has been proposed and used for describing the ecological value of forest ecosystems, evaluating management efforts to conserve biodiversity, and identifying natural, old-growth forests for purposes of establishing protection areas. Because the concept is not globally familiar, a literature review was conducted to document the ecological basis for the concept. In addition, the necessity for harmonized reporting motivated an investigation of variables that can be used to quantify and assess forest naturalness. National forest inventories (NFIs) are sources of the most comprehensive and extensive data available for assessing naturalness. However, the variety of NFI plot configurations, sampling designs, definitions, and measurement protocols greatly impedes the utility of NFI data for purposes of producing compatible estimates. As a component of a pan-European harmonization project, a three-phase investigation of harmonized approaches to assessing forest naturalness using NFI variables was conducted. Although the project was primarily European in scope, forest inventory data for an American ecoprovince were used because of their availability, comprehensiveness, and consistency. The primary result is that NFT features such as minimum dbh and plot size affect estimates of indicators of naturalness, and accommodation of their differences may be necessary if harmonized estimates of indicators of naturalness across countries are required. FOR. SCI. 58(3):294-309.