Beyond Taxonomy: A Terroir-Based Framework for Defining and Grading Hainan Oud as an Independent Material Category

Agarwood—the resinous heartwood produced by wounded Aquilaria species—commands global market prices ranging from US20 to US6, 000 per kilogram, with annual trade estimated at US6–8 billion as of 2013–2014. Despite this extraordinary economic significance, the industry operates without a standardized quality grading system applicable across production, commerce, and consumption contexts. Existing classification approaches—including Japan's six-category sensory system, Indonesia's SNI 7631: 2018 standard, China's forestry industry standard LY/T 2904-2017, and various country-specific practices—rely on subjective sensory evaluation, vary by country, and fail to account for the material and chemical distinctiveness conferred by geographic origin. This paper proposes a terroir-based framework for defining and grading Hainan Oud—resinous heartwood originating from Aquilaria sinensis cultivated in Hainan Province, China—as an origin-defined material category with an independent grading framework, distinct from generic agarwood taxonomy. Drawing on an integrative synthesis of peer-reviewed phytochemical, botanical, and sensory science literature, combined with multi-generational practitioner knowledge from Hainan's production regions, this study addresses three research questions: (1) What measurable characteristics distinguish Hainan-origin material from agarwood of other geographic origins? (2) How can these characteristics be organized into a systematic, reproducible grading framework? (3) What implications does a terroir-based material category have for industry transparency, consumer protection, and sustainable sourcing? The resulting Hainan Oud grading framework—encompassing Origin Specificity, Formation Integrity, Resin Architecture, and Scent Signature—represents, to the authors' knowledge and based on a review of English- and Chinese-language peer-reviewed literature, the first formal application of terroir theory to aromatic wood materials and offers a replicable model for origin-based quality standardization in the broader agarwood industry. This research is conducted by Yigēn Labs, the research arm of YIGEN LIMITED (Hong Kong). For the complete framework and ongoing research on Hainan Oud, visit https: //yigen. co