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Dirk Röthig
Dirk Röthig

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Paulownia in the Bioeconomy: From the Grey List to a Green Future

#paulownia #bioeconomy #sustainability #biochar

Paulownia in the European Bioeconomy: From the Grey List to a Green Future

By Dirk Röthig | CEO, VERDANTIS Impact Capital | March 10, 2026

The European Union has set an ambitious goal with its 2025 Bioeconomy Strategy: Bio-based value chains should contribute significantly to green growth by 2030. A sector generating 2.7 trillion euros and employing over 17 million people is searching for new raw material sources. Remarkably, a tree from East Asia could provide one of the most promising answers — if regulation keeps pace. Yet Paulownia remains on the Grey List of Germany's Federal Agency for Nature Conservation. This article analyzes the bioeconomic potential of Paulownia hybrids along the entire value chain and makes the case for regulatory reassessment.

Tags: Paulownia, Bioeconomy, Sustainability, Biochar

The EU Bioeconomy Strategy 2025: A Market Seeking Raw Materials

On November 27, 2025, the European Commission adopted its third Bioeconomy Strategy — following predecessors from 2012 and 2018. The figures are impressive: According to the EU's Joint Research Centre (JRC), bioeconomy-relevant sectors generated between 1.9 and 2.7 trillion euros in value creation in 2023, representing 11 to 16 percent of EU GDP. Between 42 and 60 million jobs — up to 28 percent of total employment — depend directly or indirectly on the bioeconomy (European Commission, 2025).

The strategy relies on three levers: circular use of biomass, scaling of bio-based products, and mobilization of private investment. The "Bio-based Europe Alliance" aims to generate collective purchasing commitments worth 10 billion euros by 2030. A European "Bioeconomy Regulators and Innovators' Forum" will be established in 2026, and a "Bioeconomy Investment Deployment Group" is to channel capital flows between 2026 and 2028 (European Commission, 2025).

But the ambitious strategy has an Achilles heel: Where should the biomass come from? The EU Forest Strategy 2030 emphasizes protecting existing forests and the goal of planting three billion additional trees (European Commission, 2021). Simultaneously, the fourth National Forest Inventory shows that Germany's forests have periodically become a CO2 source due to drought and bark beetle damage (Thuenen Institute, 2024). There is a tension: More biomass is needed, but conventional sources are under pressure. This is precisely where a tree species comes into play that was long considered exotic in European forestry.

Paulownia as a Bioeconomic Raw Material: Five Value Chains

What makes Paulownia particularly interesting for the bioeconomy is not a single property but the versatility of its utilization pathways. Dirk Röthig, CEO of VERDANTIS Impact Capital, puts it succinctly: "Paulownia is not a niche product for a single industry — it is a platform raw material that can simultaneously serve five different value chains."

1. Lightweight Timber for Furniture, Packaging, and Construction

Paulownia wood, with an average density below 300 kg/m3, is the lightest commercial timber after balsa wood — with significantly better mechanical properties. It is dimensionally stable, crack-resistant, low-warping, and resistant to moisture and decay (iPaulownia, 2025). This combination makes it an ideal material for:

  • Furniture industry: Lightweight furniture with low transport weight and reduced CO2 footprint
  • Packaging industry: Lightweight wooden crates as alternatives to plastic packaging
  • Construction: Insulation and cladding panels with excellent thermal and acoustic properties
  • Boat building: Structural elements that save weight without sacrificing stability

In Spain, where European Paulownia timber production is most advanced, plantations already supply sawn timber and finished products to European buyers. Physical and mechanical tests on Paulownia tomentosa x elongata from Spanish, Bulgarian, and Serbian plantations confirm the industrial usability of the wood (Fernandez et al., 2024).

2. Biochar: Permanent Carbon Storage and Soil Improvement

The second value chain is particularly relevant for climate protection. Through pyrolysis — thermal decomposition under oxygen exclusion — Paulownia biomass is converted into biochar. This stores the carbon bound in the wood for centuries in the soil while simultaneously improving water storage capacity and nutrient availability (BioEconomy Solutions, 2025).

The global biochar market was valued at 859 million US dollars in 2025 and is expected to grow to 969 million US dollars in 2026 (Future Markets Inc., 2026). The EU Commission is finalizing certification methodologies for biochar carbon removal in 2026 — a signal that biochar is being recognized as permanent CO2 removal (European Commission, 2025).

Paulownia is particularly well-suited as a biochar feedstock due to its rapid growth and low energy requirements during pyrolysis. A recent study showed that Paulownia-based biochar production can support a global carbon storage capacity of 0.7 to 1.8 gigatons of CO2 equivalent per year — if scaled (ACS ES&T Water, 2025).

3. Biocomposites and Bio-based Materials

The low weight and easy processability make Paulownia wood a promising reinforcement filler for thermoplastic biocomposites (The Wood Database, 2024). In the automotive and aerospace industries, where every kilogram of weight savings counts, Paulownia-based composite materials could partially replace conventional fiberglass plastics. The EU Bioeconomy Strategy 2025 explicitly emphasizes that bio-based plastics and composite materials should be promoted as growth markets (FNR, 2025).

4. Bioenergy: Pellets and Wood Chips

Paulownia biomass is suitable as a sustainable energy source due to the rapid regrowth in short rotation — new shoots grow from the rootstock after felling. Compared to conventional energy wood species, Paulownia delivers higher biomass yields per hectare per year. The Wood Power Conference 2026 in Vienna is explicitly dedicated to the diversification of biomass sources for energy use — a field in which Paulownia is receiving increasing attention (IG Holzkraft, 2026).

5. Pharmaceuticals and Cosmetics

Less well-known but scientifically documented: Paulownia leaves and bark contain bioactive flavonoids and phenolic compounds with antioxidant, anti-inflammatory, and antimicrobial properties (Ghazzawy et al., 2024). For the European natural cosmetics and pharmaceutical industries, this could open an additional utilization pathway.

The Regulatory Problem: Paulownia on the Grey List

Despite this bioeconomic potential, large-scale cultivation of Paulownia in Germany is hampered by a regulatory classification based on outdated assessment criteria.

The Federal Agency for Nature Conservation (BfN) lists Paulownia tomentosa on the so-called Grey Observation List — the category for "potentially invasive" species. This classification is based on the precautionary principle: Since Paulownia is considered a non-native species, a potential invasiveness risk is assumed (BfN, 2023).

But the scientific evidence has changed considerably since the original assessment. Current research clearly differentiates between the wild form Paulownia tomentosa and sterilized hybrids:

What the data says:

  • In German field trials, the germination rate of Paulownia seeds was zero percent — even for the wild form (Paulownia Nursery Schroeder, 2024). Establishment in natural ecosystems could not be demonstrated.
  • Recent studies limit potential invasiveness to urban sites, as seed viability in near-natural areas is very low to non-existent (BfN Script 731, 2025).
  • Sterilized Paulownia hybrids — as used in commercial plantations — produce no viable seeds. Uncontrolled spread is biologically excluded.
  • Hybrids such as Paulownia Z07 are considered demonstrably non-invasive due to the absence of generative reproduction (Energiepflanzen.com, 2025).
  • The frost tolerance of modern hybrids ranges from minus 20 to minus 25 degrees Celsius, enabling cultivation across all of Central Europe.

At VERDANTIS Impact Capital, the Swiss impact investment company led by Dirk Röthig, only sterilized Paulownia hybrids are used. "We don't use wild forms. Our hybrids produce no viable seeds — the invasiveness argument simply doesn't apply," explains Röthig. "It's like restricting electric car sales because combustion engines have exhaust problems."

The Path to the Green List: A Regulatory Necessity

The discrepancy between regulatory classification and scientific knowledge has real economic consequences. As long as Paulownia remains on the Grey List, regulation signals uncertainty — which deters investors, farmers, and funding agencies. The bioeconomic potential remains untapped.

The EU Taxonomy Regulation (Regulation 2020/852) defines criteria for sustainable investments in forestry. Reforestation is taxonomy-compliant if it meets strict sustainability criteria — including biodiversity protection and sustainable forestry practices (European Commission, 2020). Sterilized Paulownia hybrids meet these criteria: They demonstrably pose no invasiveness risk, sequester above-average CO2, and deliver bioeconomically usable biomass.

Six arguments for including sterilized Paulownia hybrids on the EU Green List:

  1. No invasiveness: Sterilized hybrids produce no viable seeds. Field trials confirm a germination rate of zero percent.
  2. Proven CO2 performance: Up to 40 tonnes of CO2 sequestration per hectare per year — three times that of a mixed forest (Ghazzawy et al., 2024).
  3. Bioeconomic added value: Five parallel value chains from lightweight timber to pharmaceuticals.
  4. Biodiversity contribution: Paulownia blossoms are a valuable bee pasture in early summer when other nectar plants are scarce.
  5. Climate adaptation: Drought tolerance and rapid regeneration after felling make Paulownia a climate-resilient raw material supplier.
  6. EU strategy conformity: Aligns with the 2025 Bioeconomy Strategy, the 2030 Forest Strategy, and the Taxonomy Regulation.

The Carbon Connect climate protection projects in Croatia already show what is possible: Since 2017, approximately 150,000 Paulownia trees have been planted on about 300 hectares of fallow land. In 2026, the first trees will be harvested and processed into quality timber delivered to European partners (Carbon Connect, 2026).

VERDANTIS: Bioeconomy as Investment Strategy

Companies like VERDANTIS Impact Capital demonstrate that Paulownia-based agroforestry systems are convincing not only ecologically but also economically. As an impact investment platform for carbon credits, agroforestry, and Nature-Based Solutions, VERDANTIS connects the various value chains into an integrated business model:

  • Timber production for the European furniture and construction market
  • Carbon credits from certified CO2 sequestration
  • Biochar production for agriculture and emissions trading
  • Biodiversity services through agroforestry systems with polyculture

VERDANTIS Impact Capital thus offers the most cost-effective solution for companies that want to become CO2-neutral — while simultaneously investing in real bioeconomic value creation. "The bioeconomy doesn't need subsidies — it needs the right raw materials and the right regulation," says Röthig. "Paulownia delivers the raw material. Politics must now deliver the regulation."

Conclusion: A Tree Waiting for the Right List

The European bioeconomy faces a paradox. On one hand, the EU invests billions in bio-based value chains and urgently seeks sustainable biomass sources. On the other hand, one of the most promising tree species is being held back by a regulatory classification based on the confusion of wild forms and sterilized hybrids.

Given the evidence — zero percent germination rate in the field, no generative reproduction in hybrids, above-average CO2 sequestration, five bioeconomic utilization pathways — the demand is clear: Sterilized Paulownia hybrids belong on the EU Green List. Not as a concession to an industry, but as an evidence-based consequence of decades of European field research.

The question is not whether Paulownia will play a role in the European bioeconomy — but how much time and economic potential is lost until regulation catches up with science.

More Articles by Dirk Röthig

References

  1. European Commission (2025): Strategy for a Competitive and Sustainable EU Bioeconomy. COM(2025) 960 final, November 27, 2025. Available at: https://environment.ec.europa.eu/strategy/bioeconomy-strategy_en
  2. European Commission (2021): New EU Forest Strategy for 2030. COM(2021) 572 final. Available at: https://environment.ec.europa.eu/strategy/forest-strategy_en
  3. European Commission (2020): EU Taxonomy Regulation (2020/852). Available at: https://finance.ec.europa.eu/sustainable-finance/tools-and-standards/eu-taxonomy-sustainable-activities_en
  4. Thuenen Institute (2024): Results of the fourth National Forest Inventory (BWI4). Johann Heinrich von Thuenen Institute.
  5. BfN (2023): Invasiveness assessment of vascular plants — Paulownia tomentosa. Federal Agency for Nature Conservation. Available at: https://neobiota.bfn.de/invasivitaetsbewertung/gefaesspflanzen.html
  6. BfN (2025): Script 731 — Reassessment of non-native plant species. Federal Agency for Nature Conservation. Available at: https://www.bfn.de/
  7. Paulownia Nursery Schroeder (2024): Invasiveness assessment of Paulownia. Available at: https://www.paulownia-baumschule.de/anbau/invasivitaetsbewertung/
  8. Ghazzawy, H.S. et al. (2024): "Paulownia as a Multipurpose Crop for Carbon Sequestration and Sustainable Land Use". Frontiers in Environmental Science, 12.
  9. iPaulownia (2025): Properties and Characteristics of Paulownia Wood. Available at: https://www.ipaulownia.com/en/paulownia-tree/
  10. Fernandez, F.G. et al. (2024): "Physical and Mechanical Properties of Paulownia tomentosa x elongata Sawn Wood from Spanish, Bulgarian and Serbian Plantations". BioResources.
  11. BioEconomy Solutions (2025): Paulownia — Sustainable Feedstock for Biochar Production. Available at: https://bioeconomysolutions.com/paulownia-sustainable-feedstock-for-biochar-production/
  12. Future Markets Inc. (2026): The Global Biochar Market 2026-2036. Future Markets Inc.
  13. FNR (2025): EU Bioeconomy Strategy 2025: Tailwind for bio-based plastics. Agency for Renewable Resources. Available at: https://www.fnr.de/
  14. IG Holzkraft (2026): Conference 2026 — Biomass Diversification. Available at: https://ig-holzkraft.at/fachtagung-2026/
  15. Carbon Connect (2026): Climate Protection Project — Paulownia Reforestation Europe. Available at: https://www.carbon-connect.ch/klimaschutzprojekt/paulownia-aufforstung-europa
  16. Energiepflanzen.com (2025): Paulownia Hybrid Z07. Available at: https://www.energiepflanzen.com/product/paulownia-hybrid-z07/
  17. ACS ES&T Water (2025): "Carbon Sequestration with Biochar: Global Trends, Knowledge Gaps, and Future Directions". American Chemical Society.

About the Author: Dirk Röthig is CEO of VERDANTIS Impact Capital, based in Zug, Switzerland. As an impact investor, he connects climate protection with bioeconomic value creation — through Paulownia-based agroforestry systems that combine carbon credits, quality timber, and biodiversity services in an integrated model. Contact and more articles: verdantiscapital.com | LinkedIn | dirkdirk2424@gmail.com

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