American walnut is one of the most sought-after species in markets across the world and is unique to North America.
Juglans nigra
black walnut
American walnut trees grow very widely across the eastern USA in mixed hardwood forests and on farms, concentrated in central states but spread from Texas to the eastern seaboard. The trees are one of the few hardwood species planted as well as occurring and regenerated naturally. They grow relatively tall and straight with few lower branches.
FIA data shows U.S. walnut growing stock is 137.8 million m3, 0.9% of total U.S. hardwood growing stock. American walnut is growing 4.8 million m3 per year while the harvest is 1.9 million m3 per year. The net volume (after harvest) is increasing 2.9 million m3 each year. U.S. walnut growth exceeds harvest in all major supplying states except Michigan.
Global Warming Potential | Primary Energy Demand from Resources | Primary Energy Demand from Renewables | Acidification Potential | Freshwater Eutrophication Potential | Marine Eutrophication Potential | Photochemical Ozone Creation Potential | Resource Depletion | |
---|---|---|---|---|---|---|---|---|
Unit | Kg CO2 -eq | MJ | MJ | Moles of H+ eq. | Kg P -eq | Kg N -eq | Kg NMVOC | Kg Sb -eq. |
Forestry | / | 320 | 11500 | 0.347 | / | 0.000413 | 0.436 | 0.0000025 |
Drying | 58.7 | 890 | 1670 | 0.421 | 0.000925 | 0.0285 | 1.53 | 0.0000439 |
Sawmill | -146 | 832 | 2310 | 0.265 | 0.000164 | 0.00539 | 0.189 | 0.000226 |
Transport Forest-Kiln | 55.4 | 766 | 12.3 | 0.255 | 0.00039 | 0.0065 | 0.32 | 0.0000335 |
Transport Kiln-Customer | 214 | 2860 | 43.3 | 3.16 | 0.00102 | 0.0591 | 2.46 | 0.00012 |
Carbon uptake | -2930 | / | / | / | / | / | / | / |
Total | -2750 | 5670 | 15500 | 4.44 | 0.0025 | 0.0999 | 4.94 | 0.000426 |
Walnut from the USA is available as sawn lumber and as veneer. The lumber is generally sold un-steamed and unselected for colour. Specialist producers may offer steamed walnut intended to darken the sapwood and thus reduce the colour difference between heartwood and sapwood. Recent years have seen huge global demand for this species. NHLA Grading Rules are modified for walnut, allowing smaller specifications and smaller clear cuttings and sapwood is admitted without limit. Consultation with suppliers is recommended.
Walnut is tough, hard and of medium density. It has moderate bending and crushing strengths and is low in stiffness. It has good steam bending classification.
Walnut is considered one of the supreme species for high end furniture, cabinets, doors and interior joinery. It is used for flooring and panelling and it is widely used to contrast with other hardwoods.