A sheet material is produced by pressing to sheet form in the presence of water a material derived from a plant of the type Beta Vulgaris (sugarbeet and beetroot). Fresh plant material can be used as well as plant material already used for sugar production. The plant material preferably has a particle size of 0.1 to 10 mm. The sheet material may be water soluble or water insoluble the latter condition being achieved by mixing with the plant material a dialdehyde, such as glyoxal, dialdehyde starch or other bivalent substance capable of reacting with hydroxyl groups or by heat treatment or a combination of both. The degree of water solubility of the sheet material can be controlled in this way. The sheet material can be expanded by thermal shock treatment. The sheet material may be used as a smokey generating agent by incorporating wood dust with the plant material, as a fertilizer by incorporating fertilizing salts with the plant material, as a tobacco extender by incorporating tobacco with plant material and as fish or animal fodder by incorporating food products with the plant material. The sheet material also has other applications such as in the building and paper industry.