Understanding and controlling transport of ions and small molecules throughout wood and lignocellulosic biomass is critical to both biorefining and materials applications. For example, biological conversion scenarios use thermochemical pretreatments to enhance the yields of enzymatic hydrolysis . Such pretreatments involve infiltration of the biomass with mineral acids and bases such as sulfuric acid and sodium hydroxide, which diffuse into cell walls to depolymerize non-structural polysaccharides and thereby provide better access for cellulase enzymes during saccharification . Similarly, biomass fractionation processes often require diffusion of small molecular solvents into the cell walls to enable extraction of select biopolymer components .