A. Relevance and sustainability context
A.1 Policy relevance
The gross increment indicator measures the annual growth of forest biomass and reflects the productive capacity and long-term sustainability of forest resources. It is highly relevant for forest policy, climate policy and national greenhouse gas reporting, as it provides essential information on biomass availability, carbon sequestration potential and the balance between forest growth and wood utilization.
A.2 Sustainability and / or comparative evaluation options
Sustainability perspective: Gross increment can be compared with growing stock levels, species composition and potential increment under close-to-natural forest management or reference scenarios. It provides an indication of whether forest use remains within sustainable ecological boundaries.
Bioeconomy perspective: Gross increment can be related to domestic wood biomass demand for material and energy uses. This enables assessment of how much of the forest growth potential is required to support the bioeconomy and whether future demand remains compatible with sustainable supply levels.
B. Data availability
B.1 Stage of development
Established indicator. The indicator is already used and based on established monitoring systems.
B.2 Data sources
Historical data: National Forest Inventory (Bundeswaldinventur, Thünen Institute).
Future projections: German Projection Report and forest-related scenario studies such as the DIFENs project (Dealing with Impacts on Forests under changing End-use demand, climate change, Natural disturbances and Policy goals). Additional evaluation of model outputs may be required.
B.3 Coverage over time and replicability
Historical values are available approximately every five years (NFI (national forest inventory) and CI (carbon inventory) data from 2002, 2007, 2012, 2017, 2022). Future projections are available or can be generated up to 2050, either at five-year intervals or annual resolution depending on the scenario framework. The indicator is highly replicable due to the established inventory methodology.
B.4 Coverage across scales and sectors; compatibility
The indicator is available for the German forestry sector at a national scale. Historical data may also be disaggregated to the federal-state level. The indicator is compatible with national forest monitoring and climate reporting systems.
C. Considerations for operationalization
C.1 Feasibility: Fit for monitoring
Robustness ranking: very robust. Historical estimates are highly robust, while future projections are associated with greater uncertainty due to assumptions on forest development, management and climate impacts.
C.2 Institutions
Historical monitoring is primarily carried out by the Thünen Institute. Future projections may involve the Thünen Institute, Öko-Institut and other research institutions depending on the selected scenario framework.
C.3 Future prospects
The continuation of monitoring is considered highly likely. The indicator is already established and integrated into existing forest monitoring activities.
C.4 Costs, considerations and reproducibility
Costs mainly arise from collection and processing of inventory data, scenario modelling and graphical presentation. Since the underlying monitoring infrastructure already exists, reproducibility is high.
C.5 Potential for automation
Partial automation is feasible, particularly for data processing, indicator calculation and visualization. However, expert knowledge will remain necessary for interpretation and scenario assessment.
C.6 Presentation options and breakdown / sub-indicator needs
The indicator can be presented as:
- Time series trends;
- Different measurement units (e.g. m³, carbon stock, CO₂ equivalents);
- Differentiation by coniferous and broadleaved species;
- Historical and projected development pathways.
C.7 Potential for scenario integration
The indicator has high potential for integration into future scenarios and is already routinely applied in forest and climate modelling exercises.
C.8 Interlinkages and alignment with other monitoring activities
The indicator is closely linked to:
- National greenhouse gas reporting;
- Forest resource assessments;
- Forest growth and productivity monitoring;
- Bioeconomy monitoring related to biomass supply and resource availability.
Further Comments:
To assess sustainability and bioeconomy relevance, the gross increment indicator should ideally be interpreted together with harvest, growing stock and wood demand indicators. Repeated forest inventory data combined with material flow accounts and future demand scenarios provide the most meaningful framework for evaluation. Consistent modelling assumptions across forest growth and demand projections are important to ensure comparability over time.