Abstract: The invention relates to a wood-treatment method comprising in situ polymerisation under electromagnetic radiation. The inventive method comprises the following steps, namely: a first step consisting in impregnating a piece of wood with organic monomers that are selected from among (A) drying oils and/or (B) at least one first reactant comprising at least two glycidyl functions and at least one second reactant comprising at least two primary amine or secondary amine —NH functions, the average functionality of all of the first and second reactants being strictly greater than 2; and a second step consisting in exposing the wood thus impregnated to electromagnetic radiation having a wavelength (?) of between 1 and 10?3 metres over a total time of between 5 and 40 seconds and with a power of between 300 and 1000 Watts.