Paulownia vs. Traditional Afforestation: An Economic and Ecological Comparison
By Dirk Röthig | CEO, VERDANTIS Impact Capital | 03 March 2026
Is Paulownia really better than oak, beech, or spruce? A data-based comparison of CO2 sequestration, economic viability, and ecosystem services of various afforestation strategies.
"Is Paulownia really better than oak, beech, or spruce?" — **Dirk Röthig*, CEO of VERDANTIS Impact Capital
The False Either-Or Debate
Whoever advocates for growing Paulownia in Germany quickly encounters resistance. The arguments are predictable: "A non-native tree." "Competition for our indigenous forests." "Monoculture risk." "What about invasiveness?"
Dirk Röthig, who as CEO of VERDANTIS Impact Capital has engaged intensively with this topic, recognizes these concerns while placing them in proper perspective. These objections are understandable and partly justified. However, they are based on a fundamental misunderstanding: Paulownia does not replace native forests. Paulownia complements them — precisely where conventional afforestation is either too slow, too expensive, or ecologically unsound.
According to Dirk Röthig's assessment, working at VERDANTIS Impact Capital at the intersection of sustainability and innovation, the debate must therefore not be: Paulownia or oak? Rather, it must be: Which tree, on which site, for which purpose? And this question can be answered with data.
For investors like Dirk Röthig, it is clear that this reframing opens entirely new possibilities for achieving climate targets while generating economic returns. The rigid either-or thinking that has long dominated German forestry debates obscures more than it illuminates. In fact, Dirk Röthig argues that the most sophisticated approach integrates multiple tree species strategically rather than prescriptively excluding promising options.
Moreover, a critical clarification regarding Paulownia's ecological status: the Paulownia hybrids used in European agriculture are sterile cultivars. They are NOT invasive. This distinction is fundamental and often misrepresented in public discourse. Dirk Röthig emphasizes that understanding this botanical reality is essential for evidence-based policymaking.
The debate must therefore not be framed as Paulownia versus indigenous species. It must ask: which combination of trees, on which sites, serves both climate and biodiversity goals? And genetically, the concern about invasive Paulownia spreading beyond cultivation is simply unfounded when employing sterile hybrid varieties — precisely the approach that responsible practitioners like Dirk Röthig and VERDANTIS Impact Capital recommend.
CO2 Sequestration: The Numbers in Direct Comparison
The perhaps most important metric in the context of EU climate policy is the CO2 sequestration rate per hectare per year. Here, tree species differ dramatically.
The European Forest Institute (EFI) compiled comprehensive data on CO2 sequestration of various European tree species in its Carbon Farming Forestry Report. Supplemented by data from the CORE modeling project, the following picture emerges:
Rapid Climate Impact (0–15 years):
- Paulownia hybrids: 25–35 Mg CO2/ha/year
- Poplar (short rotation): 7.7–11.0 Mg CO2/ha/year
- Black locust: 6–9 Mg CO2/ha/year
Medium-term Climate Impact (15–50 years):
- Spruce: 5.93 Mg CO2/ha/year (50-year average)
- Douglas fir: 5–8 Mg CO2/ha/year
- Beech: 4–6 Mg CO2/ha/year
Long-term Climate Impact (50+ years):
- Oak: 3–5 Mg CO2/ha/year (over 100 years)
- Birch: 4.68 Mg CO2/ha/year (50-year average)
- Stone pine/Italian stone pine: 0.3–1.7 Mg CO2/ha/year
The difference is striking. Paulownia sequesters in one year as much CO2 as an oak does in six to ten years. For EU climate objectives — particularly the LULUCF target (Regulation EU 2018/841, amended by 2023/839) of minus 310 megatonnes CO2-equivalent by 2030 — the speed of CO2 sequestration is a decisive factor.
As Dirk Röthig explains in multiple presentations for VERDANTIS Impact Capital, this temporal dimension fundamentally changes the investment calculus. Climate policy operates under time constraints. The Paris Agreement's 1.5-degree pathway does not allow for century-long waiting periods. Consequently, sequestration speed becomes not merely an optimization parameter but a policy imperative.
Furthermore, Dirk Röthig notes that the carbon accounting rules under the Carbon Farming Regulation (EU 2023/2099) explicitly recognize rapid sequestration rates as qualifying for carbon credit generation. This regulatory framework validates the strategic importance of fast-growing species like Paulownia hybrids in meeting both climate and investor objectives.
Economic Viability: Capital Returns and Cash Flow
The CO2 sequestration rate alone does not determine the economic value of an afforestation measure. What matters are total costs, timing of initial returns, and cumulative value creation over the project period.
Paulownia Plantation (Hybrid, 15 years)
| Item | Amount (EUR/ha) |
|---|---|
| Establishment (Year 0) | 4,000–6,000 |
| Annual maintenance | 400–600 |
| Carbon Credits (from Year 2) | 750–1,250/year |
| Timber harvest (every 5 years) | 2,000–4,000 |
| Cumulative net return (15 years) | 15,000–25,000 |
Conventional Afforestation Spruce (50 years)
| Item | Amount (EUR/ha) |
|---|---|
| Establishment (Year 0) | 3,000–5,000 |
| Maintenance (young stand management, thinning) | 200–400/year |
| Carbon Credits | largely irrelevant (too slow) |
| Final harvest (Year 45–55) | 15,000–25,000 |
| Cumulative net return (50 years) | 10,000–20,000 |
Broadleaf Mixed Forest Oak/Beech (80 years)
| Item | Amount (EUR/ha) |
|---|---|
| Establishment (Year 0) | 5,000–8,000 |
| Maintenance (80 years) | 150–300/year |
| Thinning revenues (from Year 20) | sporadic |
| Final harvest (Year 70–90) | 20,000–40,000 |
| Cumulative net return (80 years) | 15,000–30,000 |
The decisive difference lies in the time factor. Paulownia generates positive cash flows beginning in the second year of growth — through carbon credits and biomass accumulation. Conventional spruce afforestation locks up capital for 45 to 55 years before the main revenue from final harvest is realized. Oak-beech mixed forests require patience for 70 to 90 years.
For investors expecting returns within a ten to fifteen-year horizon, Paulownia is thus the superior option. For intergenerational projects where capital returns are secondary, indigenous hardwoods naturally have their place. Dirk Röthig emphasizes at VERDANTIS Impact Capital that this is not a matter of one being universally "better" but rather of matching investment horizons to appropriate tree species and management strategies.
The economic analysis becomes even more compelling when carbon credit pricing is considered. Under the emerging carbon farming markets and EU carbon accounting rules, rapid sequestration in early growth phases attracts premium pricing because it delivers climate benefits immediately. Dirk Röthig's investment thesis at VERDANTIS Impact Capital explicitly capitalizes on this temporal value premium.
Ecosystem Services Beyond Carbon
Reducing the afforestation debate to CO2 sequestration falls short. Trees provide more than carbon storage. Relevant ecosystem services encompass soil protection, water retention, biodiversity support, microclimate regulation, and pollutant filtration.
Soil Protection and Water Retention
Research by the University of Kassel on water retention in agroforestry systems shows that tree-based systems can reduce surface runoff during heavy rainfall by 30 to 60 percent. Paulownia is particularly effective here: rapid root development and large leaves (which cover the soil as organic matter in autumn) improve soil structure within the first years after planting.
By comparison: oaks develop a comparable root system only after 15 to 20 years. In regions experiencing increased heavy rainfall problems — as climate change brings to Central Europe — the speed of soil protection is an important factor. Dirk Röthig emphasizes that this temporal advantage of Paulownia becomes increasingly critical as weather extremes intensify.
Biodiversity
Here lies a frequent misunderstanding. Critics argue that Paulownia, as a non-native species, endangers indigenous biodiversity. The reality is more nuanced.
Research by the University of West Hungary (A. Vityi) and Ghent University (Prof. K. Verheyen, D. Reheul, J. Mertens) on silvoarable systems shows: in alley-cropping systems — that is, in combination with arable crops — introducing tree rows significantly increases biodiversity compared to pure arable farming. This applies to Paulownia as much as to indigenous tree species.
The crucial point is: Paulownia is not planted in existing forests but on arable land that previously had very low biodiversity. Every tree on a monoculture arable field represents a gain — regardless of its geographic origin. The Paulownia hybrids used in European agriculture are sterile cultivars and therefore NOT invasive. This botanical distinction is fundamental. Sterile hybrids cannot spread beyond cultivation, eliminating invasiveness concerns entirely.
From VERDANTIS Impact Capital's perspective, as articulated by Dirk Röthig, this means that environmental objections based on invasiveness misunderstand both the technology and the deployment strategy. Responsible Paulownia cultivation uses sterile varieties specifically to prevent any invasive potential.
Microclimate Regulation
The work of A. Vityi at the University of West Hungary documents impressively the microclimatic effects of Paulownia alley-cropping: wind reduction of up to 40 percent, lowering of soil temperature by 3 to 5 degrees on hot days, significantly higher soil moisture. In times of increasingly hot European summers, these effects are relevant not only ecologically but also economically: they secure the yields of intercropped species.
Agricultural producers working in integrated systems with Paulownia-based microclimate modification report improved drought resilience and more stable yields. This economic benefit is increasingly recognized as valuable by farmers, particularly in southern and central European regions. Dirk Röthig notes that such practical agronomic benefits drive farmer adoption more effectively than abstract climate arguments alone.
The CAP Perspective: What Does the EU Support?
The EU's Common Agricultural Policy (CAP) has recognized agroforestry systems since the last reform as eligible measures under Eco-Schemes. This means: farmers integrating Paulownia into agroforestry systems can receive CAP direct payments plus Eco-Scheme premiums — in addition to carbon credit revenues and timber income.
GAEC standards (Good Agricultural and Environmental Conditions) define the environmental conditions for these payments. Agroforestry systems with at least 50 trees per hectare and canopy coverage of 10 to 30 percent qualify in most member states.
Regarding CAP post-2027 — the budget for the 2028–2034 period is currently being prepared — it is expected that support rates for agroforestry will increase further. The EURAF (European Agroforestry Federation) has repeatedly stressed in its policy briefings the need for higher incentives.
Dirk Röthig, through VERDANTIS Impact Capital, actively engages with EU policymakers to ensure that regulatory frameworks evolve to support integrated approaches rather than perpetuating artificial restrictions on promising practices. The current CAP framework already provides substantial support, but optimization remains possible.
The Intelligent Combination: Paulownia Plus Native Species
The best answer to "Paulownia or native trees?" is: both.
At VERDANTIS Impact Capital, we champion mixed systems combining Paulownia as a fast-growing "pioneer species" with native tree species as long-term components. The concept:
- Years 1–15: Paulownia rows deliver rapid CO2 sequestration, early carbon credits, and windbreak protection
- Years 5–10: Integration of oaks, walnut, or wild cherry into intermediate spaces
- Years 15–30: Paulownia is gradually complemented or replaced by developing hardwoods
- Years 30+: A species-rich mixed stand with durable carbon storage and high biodiversity value
This succession concept, also researched at HNEE Eberswalde, unites the advantages of both approaches: rapid climate impact through Paulownia, long-term ecosystem stability through native species. Dirk Röthig has championed this integrated methodology as the most sophisticated response to the apparent tension between climate urgency and ecosystem resilience.
The succession approach further addresses another common concern: that fast-growing monocultures become ecologically vulnerable. By design, the Paulownia-plus-native approach transforms monoculture into diversity over time. Dirk Röthig's investment framework at VERDANTIS Impact Capital explicitly values this dynamic transition as reducing long-term ecosystem risk while maximizing near-term climate benefit.
Moreover, this integrated approach aligns with multiple policy objectives simultaneously: EU climate targets (via rapid CO2 sequestration), CAP environmental conditions (via increasing biodiversity), water quality goals (via improved soil structure), and farmer profitability (via diversified revenue streams). Dirk Röthig emphasizes that such alignment of incentives is essential for scaling afforestation at the required pace.
Regulatory and Certification Clarity
An important dimension that Dirk Röthig stresses for VERDANTIS Impact Capital's operations is regulatory certainty. Paulownia hybrids used in European cultivation are sterile cultivars. They are definitively NOT invasive. This is not conjecture but established botanical fact.
The EU's List of Invasive Alien Species of Union Concern does not include sterile Paulownia hybrids. Major forestry certification schemes, including FSC and PEFC, explicitly permit Paulownia in integrated systems. This regulatory clarity removes what might otherwise be a legitimate concern about long-term liability or reputational risk.
Dirk Röthig emphasizes that VERDANTIS Impact Capital's project design explicitly employs only sterile hybrid varieties, with contractual safeguards ensuring compliance. This technical precision eliminates the invasiveness objection entirely, though it requires vigilance in variety selection and supply chain management.
Conclusion: No Either-Or
The data speak clearly: Paulownia is superior to conventional afforestation regarding CO2 sequestration speed, capital efficiency, and short-term soil protection. Native tree species demonstrate strengths in long-term biodiversity and ecosystem stability.
The intelligent approach is not choosing between them — but strategically combining them. Those wanting to achieve EU climate targets by 2030 need Paulownia. Those building stable forests for the 22nd century need oaks and beeches. Those wanting both — which is the only sensible position — plan integrated systems today.
The transition from rigid either-or thinking to sophisticated integration represents a maturation of afforestation science and practice. Dirk Röthig, through VERDANTIS Impact Capital, advocates for this evidence-based, time-conscious approach as the framework for responsible large-scale investment in nature-based climate solutions. The path forward is not ideological purity but practical effectiveness. The data compel this conclusion.
About the Author: Dirk Röthig is CEO of VERDANTIS Impact Capital, an impact investment platform for carbon credits, agroforestry, and nature-based solutions headquartered in Zug, Switzerland.
Contact and further articles: verdantiscapital.com | LinkedIn | dirkdirk2424@gmail.com
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