Large- scale forest restoration solutions for resilience to multiple climate stressors in North Rhine-Westphalia, Germany

Since 2018, about 145,000 hectares of Norway spruce forest in North Rhine-Westphalia (about 15.5% of total forest area, about 52% of spruce area) has been damaged by wind, drought and subsequent European spruce bark beetle outbreaks, on soils and at low-elevation sites often unsuitable for spruce, following historical conversion of naturally broadleaved forest to conifer stands to meet 19th-century mining timber demand.

Demonstrate feasible large-scale restoration of climate-adapted, multifunctional mixed forests (following NRW's 'four tree species' silvicultural principle) that restore wood production, carbon storage, biodiversity, water and recreation services, while engaging diverse forest-owner types and addressing deer-browsing pressure.

Across seven demonstration sites (owned by the state forest service, municipalities, a forest-owner cooperative, a private forest, and church forests), 30-70% of each plot is replanted with at least four tree species selected against pre-defined 'forest development types' (WET) matched to site conditions and RCP4.5/8.5 projections, with the remainder left to natural regeneration; two reference stands (one fenced, one unfenced) were established per site. Baseline forest inventories were completed, with follow-up monitoring (including soil carbon/microbial sampling and citizen-science species verification via the iNaturalist app) planned for 2024-2025.

The overall SUPERB project (across multiple European demonstration areas) has a total budget of EUR 20,248,122.32, of which EUR 19,996,256.25 is EU-funded under the Horizon 2020 programme (the predecessor to Horizon Europe). For a 10,000 m2 plot, broadleaf-dominated reforestation (7,000 m2 planted) is estimated to cost EUR 13,000-17,700, and conifer-dominated reforestation EUR 8,400-13,100 (10-year costs including plants, planting, tending and fencing). Marketable timber benefits are not expected for about 30 years. Follow-up ecological and soil-monitoring results were not yet available at the time of reporting.

Stakeholder consensus on restoration goals was reached without major controversy, aided by prior engagement that began before SUPERB, and all measures were co-designed with landowners/forest managers. Three limiting factors were identified: under-representation of some stakeholder groups (e.g. recreational users) in workshops; a Natura 2000 site where the nature-conservation authority's interpretation of the landscape plan blocked the originally planned mixed-species restoration in favour of beech-only planting; and deer (including sika deer) browsing pressure requiring fencing/shelters even under intensive hunting.