In French Guiana, the development of bio-circular value chains to convert residual biomass into insulation fiberboard represents a promising opportunity to build energy-efficient houses. The objectives of this work are to select and characterize resources of interest and discuss the relationships between fiber properties, manufacturing parameters and fiberboards performances. Five local wood and bark residuals fibers are fractionated and fractions are analyzed by laser granulometry, thermal gravimetric analysis (TGA) and pyrolysis combustion flow calorimeter (PCFC). Fiberboards are produced using a thermomechanical process and their microstructure, thermal and sorption properties are characterized by X-ray microtomography, hot plate technique, and dynamic vapor sorption (DVS). Morphological analysis shows that large and elongated wood fractions allow the formation of thick and cohesive fibrous networks, while the bark small-sized fractions are more difficult to process, requiring more compaction and synthetic fibers as additives. However, despite processing difficulties, bark fiberboards show the best insulation performances, comparable to commercial reference products. In addition, TGA and PCFC tests reveal that bark fibers show better thermal stability and fire behavior compared to wood. Finally, they also show a strong affinity for water, highlighting the need for further investigations on their ageing under tropical conditions of use.