Walnut

Botanical name Juglans regia L.

Historical and cultural information
When, in June, walnut trees are loaded with green fruits, people still believe that in the year to come more boys will be born than girls. It is a given fact that this tree keeps mosquitoes and flies away, therefore it is twice as precious as a courtyard tree and for granting adequate shade in gardens and in front of inns. Similarly, chests made of this wood, which is rich in tannin, protect their contents from moths. Needless to say, this valuable wood, characterized by an attractive colour and pattern, should be used to produce wooden artefacts of excellent craftsmanship, otherwise it is wasted.

General Information
European walnut became widespread in the roman period in all of the Mediterranean area, which is how it arrived to us. It is found in the countryside and where vine is cultivated. It can be often seen in gardens and at roadsides and it is also appreciated as a courtyard tree. In our area it is not to be found in forests. It doesn’t grow well in dense forests and it has a low, broad crown. Consequently the part of trunk before branching is short. Walnut is not particularly long-living, as it can reach max. 120 – 150 years of age.

Characteristics
Walnut is defined as a semi-widespread porosity wood. The pores are widespread within the annual ring and are so large (larger in spring wood than in late wood) as to be recognizable to the naked eye, especially on longitudinal sections. The coloured stripes with a brown base - often nearly black - of the heartwood are marked in different ways. Intense light, however, causes a reduction in the stripes. A differentiation in colour according to the place of origin (Piedmont, German, French, Greek and Caucasian walnut) is no longer common in trading rotary cut veneers.

Properties
Walnut is considered to be of medium-weight to heavy (dry density 520 kg/m3); in some types hardness values can be misleading (normal value 30 N/mm2). Walnut is suitable for drying, even though this process is generally slow. It can be processed, painted and polished with very good results. The presence of alkali in the glue con lead to the appearance of marks of tannic acid. If in contact with iron, blackish-blue colouring and evident corrosion occur. As for natural durability, walnut is classified as 3; its predisposition to being attacked by harmful insects is well known to walnut furniture owners.

Use
For centuries walnut has been much sought after for manufacturing furniture and rotary cut veneers. For this reason it is more expensive compared with other national woods. Further to being used for furniture and interiors (ceiling and wall panelling) walnut can be turned and used for making musical instruments and rifle stocks. Fiddleback figured rotary cut veneers are used as an exclusive material for luxury car interiors and dashboards.