Innovative silvicultural strategies for sustainable Casuarina hybrid plantation and bioenergy production

This study explored the potential of Casuarina hybrid clone (A-01) as a promising energy crop for dendro-energy plantations, focusing on optimizing silvicultural practices like spacing and biochar application. Energy plantations, designed to produce high biomass on short rotations, play a critical role in sustainable energy solutions by providing renewable raw materials for bioenergy and reducing dependence on fossil fuels. Casuarina species, known for their adaptability to varied soil and climatic conditions, fast growth and high biomass yield, are increasingly favoured for such purposes. The Casuarina hybrid further enhances these traits, offering improved growth rates, higher wood calorific values and potential benefits in soil health and carbon sequestration. The study was conducted by establishing a research plantation trial at a farmer’s field in Coimbatore, India, from December 2023 to August 2024, the experiment utilized a split-plot design over 0.4 acres, featuring five spacing treatments (1 m × 0.5 m, 1 m × 1 m, 1 m × 1.5 m, 1.5 m × 1.5 m and 2 m × 2 m) as main plots and four biochar levels (0, 1, 2 and 3 kg/plant) as subplots, with three replications. Key findings included a maximum survival rate (100 %) under combinations A1B3, A2B2 and A4B3. Plant height after six months ranged from 277.4 cm to 416.8 cm, with the tallest plants observed in A2B4. The largest collar diameter (5.01 cm) and highest biomass (5886.8 g) were recorded in A2B4 and A2B2, respectively, while the lowest biomass (2496.6 g) was associated with A3B1. The study demonstrated the synergistic effects of optimized spacing and biochar application on the growth, biomass production and soil enhancement of Casuarina hybrid, offering valuable insights for its potential as an energy crop.