Influence of Forest Canopy Conditions on Leaf Morphology of Ardisia Gigantifolia: Implications for Sustainable Harvesting and Rural Livelihoods

Ardisia gigantifolia Stapf (Khôi tía), a shade-tolerant medicinal shrub of high pharmacological and economic value, is increasingly cultivated as a non-timber forest product under forest canopies in northern Vietnam. This study investigated leaf morphological parameters (length, width, and petiole diameter) of A. gigantifolia grown under two contrasting forest canopy types in Quang Ninh Province, northeastern Vietnam: plantation forest dominated by Aquilaria crassna (agarwood; canopy cover 0.4–0.5) and natural forest dominated by Erythrophleum fordii (ironwood; canopy cover 0.6–0.7). Leaves were randomly sampled per treatment. Mean leaf length was significantly greater under the agarwood canopy (49.12 ± 0.97 cm) than under the ironwood canopy (44.73 ± 1.31 cm; p = 0.007), and petiole diameter was similarly greater under agarwood (7.70 ± 0.19 mm vs. 6.86 ± 0.19 mm; p = 0.003). Leaf width did not differ significantly between treatments (17.15 ± 0.46 vs. 17.01 ± 0.51 cm; p = 0.83). The denser canopy of the natural ironwood forest, despite providing more shade, may restrict leaf expansion due to reduced light availability. A model household has generated 500–600 kg of dry leaves per hectare per year, with a farm-gate price of 40,000 VND/kg (approximately USD 1.6/kg), yielding a gross income of 20–24 million VND/ha/year. These findings provide practical guidance for selecting appropriate canopy types to optimise leaf yield and quality of A. gigantifolia, supporting sustainable forest management and income diversification for forest-dependent communities.