Puukuidut

Puukuidut, literally wood fibers, are natural cellulose fibers derived from trees. They are a fundamental fibrous component of wood and are produced commercially for a broad range of products, from everyday paper to advanced bio-based materials. The most common raw materials are softwoods such as pine and spruce, with hardwoods like birch or eucalyptus used for specific grades or dissolving pulps.

Production methods separate into mechanical and chemical processes. Mechanical pulping (such as groundwood or refiner mechanical pulping) preserves most of the wood’s lignin and cellulose, yielding high yields but producing fibers with a broader distribution and typically lower brightness. Chemical pulping (including kraft and sulfite processes) removes lignin to produce purer cellulose fibers with greater strength and brightness; dissolving pulps are specially produced for conversion into textile fibers through additional chemical processing (e.g., viscose or lyocell).

Properties of puukuidut vary by process and species but generally include high tensile strength, good stiffness, and notable moisture sensitivity. Fiber length and quality influence outcomes in paper, textiles, and composite materials.

Uses of wood fibers are diverse. In papermaking, they form the bulk of most papers and packaging boards. In textiles, dissolving pulps enable regenerated fibers such as viscose and lyocell. In construction and composites, wood fibers reinforce materials like fiberboard, cement boards, and some bio-based plastics. Wood fibers also appear in filtration, insulation, and specialty applications requiring renewable, biodegradable materials.

Environmental considerations emphasize sustainable forestry, responsible pulping chemistry, and energy use. Wood fibers are renewable when sourced from responsibly managed forests, but the environmental footprint depends on processing methods, chemical use, and end-of-life handling.