Features

The walnut (Juglans regia) is an impressive, deciduous tree and is the namesake of the Juglandaceae family to which it belongs. It is colloquially referred to as walnut or walnut tree, and regionally as "Baumnuss" (Switzerland) or "Welschnuss" (Austria). The Romans mainly planted this heat-demanding tree in their Gallic province, which later became France, from where it later spread to Germany. The name "walnut" (from Middle High German "welsch nuz") originally means "Roman (hence coming from the Romans) nut".

The walnut is documented as far back as the Tertiary period. It is believed to have survived the ice ages in Syria, Western and Southern Anatolia. Its native distribution in the Quaternary includes the eastern Mediterranean region, the Balkan Peninsula, and parts of the Near and Middle East. It is found in humid ravine forests of mountainous areas and grows at altitudes up to 3300 metres in the Himalaya. There are well-known walnut forests in Kyrgyzstan in the Tian Shan Mountains. Even though Kyrgyzstan is one of the least forested countries in Asia with only 4 percent forest cover, it is home to the largest walnut tree stands in the world.

The walnut is wind-pollinated, with the red mason bee collecting pollen and for its brood cells. The leaves of the walnut serve as larval food for the festoon and the goat moth. The nutritious nuts are dispersed by squirrels, mice, dormice, and large birds such as crows and Eurasian jays.

As decomposing walnut leaves secrete growth-inhibiting cinnamic acid, which is washed into the soil by the rain, there is often no grass growing under walnut trees. Juglone, a naphthoquinone released during the decomposition of walnut leaves, also contributes to this effect and is additionally responsible for its colouring properties.

Walnut wood is highly valued in carpentry. It is characterised by a light sapwood and a beautifully grained, warm brown heartwood. The wood is flexible, durable, easy to polish, and has low shrinkage when dried. It is used in exclusive interior design, for high-quality furniture, in organ and piano construction, for gunstocks, art objects, and pendulum clocks. It was already popular for furniture during the Renaissance, Baroque, and Rococo periods.