Method for chemically modifying a wood part

A method for chemically modifying a wood part comprising hydroxyl groups comprising the following steps:

• a first step of covalently reacting all or part of said hydroxyl groups with at least one non-polymeric compound, called the first compound, comprising at least one group capable of covalently reacting with a hydroxyl group, whereby, at the end of this first reaction step, the wood part is thus covalently linked to residues of the non-polymeric compound(s);
• after or simultaneously with said first step, a second step of covalently reacting all or part of the residues of the non-polymeric compound(s) with at least one second compound,
• said first step and said second step being performed in the presence of at least one supercritical fluid.