Syoji Sudo, former Head of the Materials Section, Wood Technology Division, Forestry and Forest Products Research Institute (FFPRI, Tsukuba, Japan), passed away in March 2026 at the age of 98. He was a member of the International Association of Wood Anatomists (IAWA) for more than half a century, having joined in 1958, and was elected an Honorary Member in October 1996 at the African-European Wood Anatomy Symposium held in London.

Syoji Sudo was born in Tokyo, Japan, in 1928. In 1952, he graduated from the University of Tokyo, in the field of Forestry and Wood Technology, with research focusing on the wood anatomy of the genus Picea. Following postgraduate studies, he served as a lecturer in Forestry at Shizuoka University for one year, before transferring in 1955 to the Government Forest Experimental Station in Tokyo, now known as FFPRI.

In 1959, Dr. Sudo published the influential paper "Identification of Japanese Hardwoods," which introduced a card-sorting key for wood identification. During the mid-1960s, Japan experienced a rapid increase in both volume and diversity of imported timbers, eventually accounting for approximately 50% of domestic consumption and more than 20% of global timber trade by 1979. The influx of imported timbers had a tremendous influence, not only on the wood industry but also on wood research. Wood anatomy and the properties of tropical timbers became Dr. Sudo’s principal field of expertise. In 1961, he published the book "Knowledge of Tropical Timbers". In the same year, he spent twelve months (1961– 1962) at the Forest Products Laboratory in Madison, Wisconsin, working with Dr. Kukachka. The knowledge and experience he gained during this period are reflected in his subsequent work, including "Identification of Tropical Timbers" (1963). In 1970, he consolidated his research into the widely used reference book "Timbers from Tropical Asia". Owing to its extensive use within the Japanese timber industry, a revised and expanded edition was published in 1998. Dr. Sudo received his doctorate in 1965 for further studies on the wood anatomy of the genus Picea. From 1961 to 1977, he led the long-term research project "Studies on Breeding for Wood Properties of Akamatsu (Pinus densiflora Sieb. et Zucc.)." For this series of studies, he was awarded the Japan Wood Research Society Prize in 1972. Upon his retirement in 1988, he published the research monograph "Anatomical Characters and Identification of Papua New Guinea Timber Species". One of his enduring objectives was the development of anatomical identification tools for lesser-known timber species from Asia and the Pacific region, along with clarifying relationships between wood anatomy and timber quality.

The highly original textbook "Anatomy of Wood" (1976), co-authored with Ken Shimaji and Hiroshi Harada-later all Honorary Members of the IAWA-remains a landmark publication and was reprinted in 2016, despite the later appearance of "Structure of Wood" (1985) with an expanded authorship. Through his publications, Dr. Sudo played a major role in disseminating knowledge of the anatomical identification and properties of tropical timbers, particularly those from Southeast Asia, thereby fostering both scientific research and human resource development in the region. For a broader audience, his interest in photography culminated in the illustrated guide "World Timbers in Colour" (1996), featuring macro-photographic images of the wood of 200 major timber species.

Dr. Sudo was instrumental in organizing the Pacific Regional Wood Anatomy Conference (PRWAC) at FFPRI in Tsukuba in 1984, following a request from the IAWA Executive Secretary during the IUFRO World Congress in Kyoto in 1981. PRWAC has played a key role in promoting wood anatomy research in the Asia – Pacific region, particularly by regularly convening conferences across the Asia-Pacific region, including many in developing countries. At its core, this activity was supported by the Wood Anatomy and Quality Research Group, in which Dr. Sudo played a central role. In December 2005, Dr. Sudo delivered a plenary lecture at the 6th PRWAC in Kyoto entitled "Trends in Wood Anatomy in Japan over the Past 120 Years," the substance of which was published in IAWA Journal 28(3): 259-284 (2007). In later years, he withdrew from international activities, but his influence endures through his publications and the many researchers he inspired.

Dr. Syoji Sudo is remembered with deep respect and gratitude by colleagues, students, and succeeding generations of wood scientists. Beyond his many scholarly achievements, he was valued for his quiet dedication, intellectual generosity, and unwavering commitment to advancing wood science. His work continues to guide the field, and his legacy lives on in the many researchers he mentored and inspired, as well as in the global community of wood anatomists who have benefited from his lifelong contributions.