Method of processing plant

A method for processing a plant, comprising:

• a first step including
• setting, inside a forming mold, a piece of a plant which contains moisture and which has not been reduced to a powder,
• hermetically closing the forming mold by substantially disabling ventilation of water vapor between an atmosphere inside the forming mold and an atmosphere outside the forming mold, and
• applying a heat and a pressure to the piece of the plant so as to liquid-fluidize the piece of the plant, and pressure-molding the piece of the plant thus liquid-fluidized while in the hermetically-closed state;
• a second step of, after the piece of the plant reaches a predetermined molding temperature and a predetermined molding pressure, enabling ventilation of water vapor between the atmosphere inside the forming mold and the atmosphere outside the forming mold and thereby removing moisture from a molded article made from the piece of the plant;
• and
• a third step including
• retaining the predetermined molding pressure and the predetermined molding temperature for a predetermined period;
• cooling the molded article thus made from the piece of the plant;
• and
• taking out the molded article from the forming mold,
• wherein the moisture content of the piece of the plant is not less than 10% by weight, and a pressure of 100 MPa or greater is applied to the piece of the plant while heating the piece of the plant to a temperature not less than 130° C. by not more than 200° C.