Tree Architecture, Biomass Yield, Fibre Content and Economics of Promising Eucalyptus Clones for Pulpwood Industry and Farm Forestry in Tropics

The present study evaluated fifteen superior Eucalyptus clones for their suitability in pulpwood industry and tropical farm forestry under rainfed conditions of eastern India, with emphasis on tree architecture, biomass productivity, fibre quality, and economic returns. The experiment was conducted in an 8-year-old clonal plantation at Rayagada, Odisha, India, using a randomized complete block design. Significant clonal variation was observed across all growth, root, biomass, fibre, and economic parameters, indicating strong genetic influence on plantation performance. Among all clones, JKSC-ECD (Eucalyptus camaldulensis × E. deglupta) emerged as the most outstanding genotype, recording the highest tree height (23.37 m), DBH (19.00 cm), crown volume (56.34 m³), collar girth (0.77 m), rhizosphere area (6.91 m2), and deepest root penetration (2.51 m). It also produced the maximum fresh stem wood yield (384.47 t ha−1), total fresh biomass (491.86 t ha−1), and dry biomass (335.25 t ha−1). Fibre analysis revealed superior pulpwood quality in JKSC-ECD with the highest cellulose content (45.56%) and cellulose yield (122.62 t ha−1), coupled with relatively low lignin content (24.36%), making it highly suitable for pulp and paper manufacture. Economic assessment over an 8-year rotation showed that JKSC-ECD generated the highest gross income (Rs. 12,07,114 ha−1), net return (Rs. 10,07,114 ha−1), and benefit:cost ratio (6.04), substantially outperforming all other clones. CTA-8GS274 ranked as the second-best clone in most parameters. The study establishes JKSC-ECD as the most promising elite clone for tropical pulpwood plantations, combining superior growth, fibre quality, and profitability, thereby offering a sustainable solution for industrial raw material supply and enhanced farmer income in tropical forestry systems similar to the tested site in east India.