Wood with vertically aligned tracheids has many potential applications in energy storage. Carbonized wood inherits the previous tracheid structure and has good electrical conductivity, which provides favorable conditions for its application in self-supporting electrodes of supercapacitors. However, problems such as low specific surface area, low space utilization, and hydrophobicity limit the development of wood-derived carbon (WC) as an electrode material. Here, to improve the specific surface area and tracheid space utilization of WC, a porous carbon skeleton (PCS) was simply and efficiently constructed in its interior by using glucose and sodium chloride templates, and then potassium hydroxide etching treatment was used to further improve the specific surface area and hydrophilicity of the PCS, resulting in an etched porous carbon skeleton (E-PCS). The prepared E-PCS@WC electrode had an excellent area/volumetric specific capacitance of 7.29 F cm⁻²/145.8 F cm⁻³, and the supercapacitor exhibited a high volumetric capacitance and volumetric energy density of 34.99 F cm⁻³ and 4.86 mWh cm⁻³ at a power density of 2.5 mW cm⁻². The supercapacitor constructed from this electrode exhibited good cycling stability with a retention rate of 98.5% over 20,000 cycles at a current density of 50 mA cm⁻³. This research will provide new ideas and a scientific basis for the design, construction and application of new green energy storage devices.