Objective of the method is a procedure for production of nanocellulose, where energy consumption and other costs of production are lower than in methods presented previously. It is based on separation of minute particles from cellulose or plant based ingredients by effects of light, thermal energy or water-soluble organic solvents. These particles act as precursors of nanocellulose. After separation they form in dry state aerosol, in liquid media a suspension, and combine to chains, microfibrils and secondarily formed fibrils, which form further networks with each other or with other fibres and fibrils. Applications are based on their action as reinforcing structure in composites, paper, cardboard, paints and other materials, on forming thin-layer films for electrical, electronic and medical applications, or on viscosity, surface and permeability properties.