Lexicon DIY-Knowledge


The European walnut is originally found from Southern Europe to China. With a maximum growth height of 30 m, it can reach a trunk diameter of up to 1 m. Growth is enhanced by deep, loose soils rich in nutrients and a mild climate. In its youth the tree has a smooth grey to grey-brown bark which grows into a thick grey-brown bark full of fissures and cracks. Beneath it you will find the especially in younger trees unusually wide sapwood section, white to grey-white in colour. It surrounds the rather hard, tough and medium-heavy, not very flexible heartwood which distinguishes itself by its grey to dark brown colour and its very decorative dark streaks. Under the influence of light it darkens strongly with age. Light protection through UV absorbers is possible. Colour and grain structure of walnut wood vary strongly. They depend on the origin and age of the heartwood.

Walnut trees produce a high-quality wood.
It shrinks little and can be easily and smoothly processed with all tools. All wood joining techniques like gluing, screwing and nailing can be used with lasting success.
Surface treatment like polishing, staining with mordant and varnishing do not cause any problems. However, surface film drying of oil and polyester based varnishes can be a bit of a problem with walnut. Simultaneous contact with iron and water creates a blue tint in walnut wood.
Although the walnut tree proves little resistance against moist weather conditions, it lasts well in dry conditions. Therefore it is mainly used for indoor applications. It is one of the most popular veneer woods in furniture making. Solid walnut is used to make pianos, parquetry, for carving, wainscoting and gun stocks and rifle butts. The sapwood is often included in the processing.
Since walnut varies greatly in structure and colour, the whole charge (whether it is veneer or solid wood) should be examined before further treatment or processing.
In addition to its importance as a timber tree, walnut trees were held in high esteem since ancient times as producers of delicious nuts. These can be further processed to produce edible oil, soap and oil paints.
Dried leaves, bark and nutshells can be processed with alumen to stain wood, wool and hair brown.