Black walnut
Black walnut (Juglans nigra) has a slow growth rate, preferring 1000 mm or more of annual rainfall and well drained alluvial soils. A deciduous tree that is allelopathic to many broad leaf weeds in pasture. Best situated on river flats or adjacent to waterways.
Characteristic | Description |
|---|---|
Botanical name | Juglans nigra |
Growth rate in preferred conditions | Slow |
Estimated rotation length (yr) in preferred conditions to produce 60 cm diameter at breast height | 50+ |
Preferred annual rainfall (mm/yr) | 1000+ |
Minimum rainfall (mm/yr) | 800 |
Preferred elevation (m) ASL | 0–300 |
Preferred landscape position | River flat or adjacent to waterways |
Preferred soil | Well-drained alluvial soils >1 m deep, the deeper the better for unimpeded taproot development |
Prohibitive soil | Shallow or poorly drained soil, does not tolerate exposure to harsh weather |
Poor drainage tolerance | Low |
Dry site tolerance | Very low |
Frost tolerance | Low; out-of-season frosts (e.g. in October) can affect tree form by killing the main leader. |
Pest and disease problems: | Pest and disease issues are common within its natural US range, but when sited appropriately it has experienced few problems in Gippsland. |
Table 2: Timber characteristics for black walnut
Characteristic | Description |
|---|---|
Strength: seasoned timber only | SD5: moderate |
Durability: in ground | above ground | 2 | 2 |
Drying: green to 12% moisture content | Slow to dry but minimal degrade. Shrinkage about 3.4% radial and 4.9% tangential. |
Main commercial products | Veneer, gunstocks, cabinet making |
Bushfire resistance: measured by bushfire attack level (BAL) | Not tested |
Least attractive features | Slow growth, susceptible to lyctid borer, very site-specific, not resilient to poor siting. |
Most attractive features | Deciduous – favouring pasture growth, allelopathic to many broadleaf weeds in pasture. Beautiful dark timber that is highly valued for a range of uses. Premium cabinet-making timber. |
Status as a plantation species in Gippsland | Restricted to a few isolated plantings. The narrow siting preference of the species indicates that it is not suited to being planted across large areas spanning different site classes. |
Note: Timber characteristics and durability are based on Australian Standard: Timber Natural durability ratings (AS 5604–2005). Refer to the Appendix for an explanatory table. Where (?) applied, rating is based on field experience.
Note: Bushfire resistance measurement is based on naturally bushfire resisting timbers, which are those with inherent bushfire-resisting properties. For more information refer to Australian Standard 3959:2018.
Assumptions and notes
- Sites considered for planting contain at least one metre of soil above an impeding layer (e.g., bedrock or layer impenetrable to roots).
- Please note that most (if not all) eucalypts in Gippsland grow best on sheltered sites.
- Overall slow drying time across air and kiln-dried schedules is recommended to minimise drying degrade. This is the best starting point for inexperienced operators.
References
Beadle CL and Brown AG (eds) 2007. Acacia utilisation and management: adding value. RIRDC Publication No. 07/095, Rural Industries Research and Development Corporation, Canberra.
Boland DJ et. al (1992). Forest trees of Australia. CSIRO Australia.
Bootle KR (1983). Wood in Australia – Types, properties and uses. McGraw Hill, Australia
Carnegie AJ (2002). Field guide to common pests and diseases in eucalypt plantations in NSW. Research and Development Division of State Forests, NSW.
Clarke B, McLeod I and Vercoe T (eds) 2009. Trees for farm forestry: 22 promising species. RIRDC Publication No. 09/015. Rural Industries Research and Development Corporation, Canberra.
Mortimer J (2003). A selection of alternative timbers. Taitua Books, NZ.
National Association of Forest Industries (2004). Timber species and properties, revised edition. Timber Manual Datafile P1
Nicholas ID, Gifford HH and Kimberely MO (1997). Siting black walnut. FRI Bulletin no. 188
Phillips C (1996). Insects, diseases and deficiencies associated with eucalypts in South Australia. Primary Industries SA Forests.
Poole B, Waugh G and Yang JL (2017). Potential for growing and processing durable eucalypts in New Zealand. Publication No. SWP-T036. Solid Wood Innovation. Specialty Wood Products Research Partnership.
Reid R (2017). Heartwood. The art and science of growing trees for conservation and profit. Melbourne Books.
Tepper CJ (2002). Plantation eucalypt species for solid wood products – a profile of Eucalyptus muelleriana. Gottstein Fellowship Report for the Gottstein Memorial Trust
Tepper CJ (2008). Site Matching and Establishing Eucalypt Sawlog Species in Southern Australia. In Beadle CL and Brown AG (eds) 2008. Plantation eucalypts for high value timber. RIRDC Publication No. 08/113, Rural Industries Research and Development Corporation, Canberra.