Mixing boron with two thermoreversible hydrogels, obtained from an amphiphilic tripeptide and a carbamate derivative of glycerol, respectively, allows the formation of a supramolecular network that incorporates boron and significant amounts of water upon gelification of the solution when the temperature decreases. Hydrogels obtained from these gelators were impregnated in pine sapwood blocks using vacuum pressure treatment and subjected to leaching. Results indicated that incorporation of boron salts in the hydrogel network effectively protected the wood from degradation caused by the brown rot fungus Poria placenta and from attack by termites also even after leaching. It is believed that these hydrogels fill the tracheid cell walls and lumens, limiting the leachability of boron salts when the wood is humidified.