Towards ecosystem service assessment: Developing biophysical indicators for forest ecosystem services

Forests are specifically relevant for biodiversity and provide a wide range of ecosystem services. However, Europe's forests and their services are threatened. Temperate, boreal and Mediterranean forests are facing deforestation, fragmentation and conversion due to human impact and recent developments in climatic conditions. Currently, not all forest ecosystem services are comprehensively accounted for and often, primarily timber production is considered. The aim of the present article is to further develop forest ecosystem service assessment using a systematic approach to assess biophysical indicators for ecosystem services. In this way, we aim to promote the use of forest function mapping, which is an important planning tool in the Central European forest sector for mapping forest areas of particular relevance for protection and recreation. Building on forest function mapping and the Common International Classification of Ecosystem Services (CICES 5.1), we selected six ecosystem services and propose indicators for their biophysical quantification. The indicator selection process followed specific selection criteria. We propose indicators for the potential, supply, demand and flow of the following forest ecosystem services: (i) groundwater for drinking purposes, (ii) timber provision, and (iii) global climate regulation. For the ecosystem service (iv) local air pollution reduction, indicators for potential, demand and flow are proposed, for (v) recreation, as well as (vi) education and training, indicators for the ecosystem services' supply, demand and flow are proposed. In addition, possible measuring methods and units, and necessary data sources for applying the indicators are provided.