Impregnation is a special wood treatment process that aims to protect it from microorganisms, insects and fungi.
After impregnation, the wood is slow-burning and more resistant to external conditions. Be inside a cylinder with the corresponding vacuum pressure, and channeling various chemicals. Impregnation is indicated for soft-hard wood (Fir, Pine, Pitch-pine, etc.)

There is also the method of evaptism which involves smearing the wood on its surface with the appropriate fungicides (colorless or colored).