Juglans regia
Specifications
Family
Juglandaceae
Species
Juglans regia L.
common walnut
persian walnut
royal walnut
english walnut
Description
The sapwood is grey and the heartwood is brown or dark, tending to blackish.
Plant morphology
It is a deciduous tree, 10–25 m tall, with a broad, rounded crown and smooth, light gray bark that tends to crack and lighten over time. It can live up to 400 years.
Natural occurrence
Countries of origin and distribution
Native to Asia, it was introduced to Europe in ancient times for its edible fruits; it is also widespread in America.
Habitat and ecology
It grows in climates with a long warm season and is susceptible to winter and spring frosts. It prefers deep, well-drained soil (but without stagnation); it does not tolerate long periods of drought.
Uses
Use class
CU1
CU2
CU3
CU4
CU5
Application areas
This wood is semi-hard, easy to work, very durable, and prized for its magnificent color and variegation for cabinetmaking, luxury furniture, floorboards, carving, lathe work, and specialty products (gun butts and billiard cues). The wood is an excellent fuel, producing excellent charcoal.
Threats and Conservation
Threats
The species has historically been threatened by its exploitation for timber and fruit, as well as by urban expansion and grazing areas. In Europe, the species is currently threatened by the emergence of fungal diseases caused by Armillaria mellea, Phytophthora cinamomii, and P. cambivora, which cause necrosis and leaf drop, even in summer.
Conservation measures
Germplasm from various cultivars of this species is conserved in Central Asia and is also used in research. Walnut specimens are also preserved in more than 200 ex situ collections (BGCI, 2017). The impact of plant diseases on natural populations needs to be monitored.
IUCN Red List
IUCN
LC - Least Concern - Low Risk
CITES. Year of assessment
CITES
2017
1975
2050
CITES Italia • Ultimo aggiornamento
2017
Not present.
Technical data
Aesthetic characteristics
Grain
Obvious
Texture
Medium
Physical and mechanical properties
Density
ρ
ρ
670
kg/m3
Radial shrinkage
Rad. sh.
Rad. sh.
55
MPa
Tangential shrinkage
Tang. sh.
Tang. sh.
75
MPa
Bending strength
M.O.R.
M.O.R.
117
MPa
Modulus of Elasticity
M.O.E.
M.O.E.
11800
MPa
Durability characteristics
Fungal resistance
Moderatamente durabile
Insect resistance
Resistant
Miscellaneous
The leaves and husk have bittering, digestive, purifying, hypoglycemic, hypotensive, anti-inflammatory, and antiseptic properties. The husk is also used to dye natural fabrics a deep brown color.