Unlocking the science behind faster-growing, higher-yield willow crops for a greener future
How genetics, planting materials and storage conditions transform willow regrowth potential
Imagine a renewable power source that grows rapidly, thrives in challenging conditions, and can be harvested again and again from the same plant. This isn't a futuristic fantasy—it's the reality of energy willow, a promising bioenergy crop that could play a key role in our transition to sustainable energy.
The speed at which these willows regrow their vegetative mass after harvesting is not left to chance; it is profoundly influenced by the specific willow variety chosen, the type of planting material used, and even how that material is stored before planting. This article explores the fascinating science behind maximizing willow regrowth, a field where meticulous attention to detail separates modest growth from exceptional biomass production.
Willows cultivated for biomass are typically grown in Short Rotation Coppice (SRC) systems, where high densities of trees are planted and harvested on cycles of two to five years 4 . After cutting, willows regrow from the remaining stumps, a process known as coppicing, and can do so for multiple cycles before needing replanting.
Genetic makeup is a primary dictator of growth speed and final biomass yield. Research consistently shows that different species and cultivars exhibit vast differences in their regrowth vigor 1 6 .
Willows are typically planted using vegetative cuttings rather than seeds. The form these cuttings take can influence early growth 2 .
Size and quality of the propagule are crucial - larger cuttings contain more energy reserves 6 .
The period between cutting collection and planting is vulnerable. Cuttings are living tissues, and how they are stored can make or break their viability.
To truly understand how scientists unravel the secrets of willow regrowth, let's examine a detailed field experiment conducted in Ukraine 1 .
2023 to 2024 field study at the Institute of Bioenergy Crops and Sugar Beet in Ukraine
Fast-growing 'Zbruch' basket willow vs. 'Panfylska' almond willow
Traditional stem cuttings vs. shoots with different storage treatments
Monthly tracking of plant height, stem diameter, and number of shoots throughout the growing season
The data painted a compelling picture. The 'Zbruch' variety consistently outperformed 'Panfylska' in all key biometric indicators 1 .
| Indicator | 'Zbruch' | 'Panfylska' |
|---|---|---|
| Plant Height | Taller | Shorter |
| Stem Diameter | Thicker | Thinner |
| Productive Stems | Higher | Lower |
| Indicator | Cuttings | Shoots |
|---|---|---|
| Plant Height | No significant difference | |
| Stem Diameter | No significant difference | |
Key Takeaway: Varietal characteristics dominate over planting material type
| Condition | Impact |
|---|---|
| ≤12 days out | Acceptable |
| 23 days out | Avoid |
| Return to +2°C/-4°C | Safe |
| Return to -20°C | Not Recommended |
Based on storage viability research 8
The most striking finding was that the best regrowth—in terms of both stem height and diameter—was observed in plants that combined:
This underscores that while genetics are paramount, optimizing the entire process chain from storage to planting can unlock a cultivar's full potential.
Optimal combination yields highest biomass
Essential tools and materials for willow regrowth research
Essential for maintaining cutting viability between collection and planting, preventing desiccation and premature budbreak 8 .
Lime treatment of cut ends improves survival and regrowth performance, likely by protecting against pathogens 1 .
Crucial for precise measurement of stem diameter throughout the growing season 1 .
Essential for accurate measurement of plant height during growth monitoring 1 .
Research is exploring the use of planting material collected and planted in early spring, which may accelerate establishment 2 .
Growing interest in leveraging microorganisms to enhance nutrient uptake and stress resistance naturally .
Understanding how male and female plants respond differently to stresses like drought and salinity for breeding resilient cultivars .
Identifying key genes responsible for traits like fast growth and stress tolerance through advanced genetic analysis .
The intense regrowth of willow vegetative mass is not the result of a single magic bullet. It is a carefully orchestrated symphony where varietal genetics set the melody, the type of planting material provides the rhythm, and storage conditions act as the conductor, ensuring everything comes together in harmony.
By continuing to refine our understanding of these factors, we move closer to realizing the full potential of willows as a powerful, sustainable engine for the bioeconomy of the future.