A new methodology for restraining the swelling of spruce wood samples in the micrometre range is developed and presented. We show that the restraining device successfully prevents the free swelling of wood during moisture adsorption, thus modifying significantly the anisotropy of swelling and provoking the intended collapse and large deformations of the wood cells at the edges of the sample in contact with the restraining device. The device consists in a slotted cube designed t o r e s t r a i n s w e l l i n g a n d i s m a d e o f P M M A manufactured by laser ablation. The sample undergoing the restraining experiment is imaged with highresolution synchrotron radiation phase contrast X-Ray Tomographic Microscopy. The deformation of the restraining device itself is only approximately 2 μm with respect to a 500 μm width in cubes containing latewood samples and half of that in the case of cubes containing earlywood.