A tree is a living energy-water system. Intensive study of tree-derived natural wood is of great significance for the sustainable development of human civilization and reduced dependence on nonrenewable resources. Here, we report on the mesostructures of several natural wood materials as well as their thermal conductivities and mechanical properties. We found that natural wood, including hardwood and softwood, possesses excellent hydrophilicity, an interconnected pore network, low thermal conductivity, and various mechanical properties. Inspired by the critical ecological energy-water nexus, high-efficiency solar steam generation based on natural wood is demonstrated in this work. The variation in multiple natural wood microstructures results in significantly different solar steam generation performances, with the more porous wood showing higher evaporation efficiency based on our results. The inherent rich mesostructures, aligned microchannels, and favorable hydrophilicity enable natural wood materials to be applied in many other fields of the energy-water nexus