Woody necromass is a key component of mangrove carbon dynamics, particularly in the Amazon region. Woody residues across mangrove forests of the Ajuruteua Peninsula, northeastern Amazon coast, are quantified and characterized to examine how species composition, decay class, hydrological regime, and disturbance history influence necromass structure. Using the Line Intersect Method and detailed density assessments, the study evaluates coarse and fine residues, incorporating adjustments for decomposition and void spaces. Patterns of necromass distribution reflect local forest structure, selective logging, tidal transport, and species-specific wood characteristics. Density consistently declines across decay classes, while advanced decomposition leads to convergence among species, highlighting shared structural degradation. Although stocks are lower than global averages for structurally taller Indo-Pacific mangroves, necromass remains essential for carbon storage, nutrient cycling, and habitat provision. These findings reinforce the need to incorporate woody necromass into carbon budgets and monitoring frameworks to improve blue carbon assessments in tropical coastal ecosystems.