Revised estimates of forest carbon sequestration reveal the true sink capacity of Japanese forests

for forests managed under the governmental management plan (m-NFI_1) and all forest categories (m-NFI_2), respectively. These are approximately double the estimates from the NFI based on the predictions from yield tables (p-NFI), which Japanese national and local forestry agencies have conventionally used. Notably, Cryptomeria japonica, the most important plantation tree species for timber production in Japan, has the highest area-based carbon uptake rate among the studied forest types and, despite being a single tree species, accounts for 43.1% of Japan's total annual forest carbon sequestration. Further investigation using a machine-learning algorithm revealed that the primary factor controlling total forest productivity is the forest type, followed by stem volume. Forest age and meteorological drivers are not significantly influential. We emphasize the importance of accounting for high forest productivity in planning for future forestry and carbon neutrality in Japan.