Management Information
Preventative measures: In general, blackwood is either recognised as an invader species in some areas, or it does not
invade in other areas (although its potential to invade is recognised), or its invasion status is not yet recognised. South
Africa provides information on the management of areas where blackwood invasion has become a problem (Geldenhuys, 1986 &
1996; Seydack, 2002; Vermeulen & Seydack, 2000). In areas where blackwood is not yet an invasion problem or where the species
is in an early stage of invasion, the following options could be followed:
· Be careful with the introduction of
Acacia melanoxylon into natural areas or area where the species is not present because of the potential of the species
to become invasive.
· Production of viable seed should be monitored.
· Seedling recruitment should be monitored in
natural ecosystems and along drainage lines.
Plants in natural ecosystems should be removed before they flower and
produce seed.
(Geldenhuys, pers.comm. 2003)A Risk Assessment of Acacia melanoxylon for Hawai‘i and other Pacific islands was prepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani Urban
Forestry Program and US Forest Service. The alien plant screening system is derived from Pheloung et al. (1999) with minor modifications for use in Pacific islands (Daehler et al. 2004). The result is a score of 12 and a recommendation of: "Likely to cause significant ecological or economic harm in Hawai‘i and on other Pacific Islands as determined by a high WRA core, which is based on published sources describing species biology and behaviour in Hawai‘i and/or other parts of the world."
Location Specific Management InformationChile
Instituto Forestal (INFOR, Casilla 109-C, Concepción, Chile) research explored genetic improvement, silvicultural practices and forest ownership to provide a new option for forest production. The mention of stands of natural regeneration suggests that the species may pose an invasion problem in the future. Eastern Cape (South Africa)
Acacia melanoxylon is a declared noxious weed species in South Africa. KwaZulu-Natal (South Africa)
Acacia melanoxylon is a declared noxious weed species in South Africa. Limpopo (South Africa)
Acacia melanoxylon is a declared noxious weed species in South Africa. Mpumalanga (South Africa)
Acacia melanoxylon is a declared noxious weed species in South Africa. New Zealand
Stands are managed silviculturally for the production of good quality logs for sawn timber for the furniture industry. A field study in 2001 of stands between 17 and 34 years old showed no evidence that blackwood will invade native ecosystems of Westland in the South Island. Blackwood regeneration occurred in some stands but the active native vegetation was out-competing the young blackwood regeneration. Observations during November 2002 around several blackwood stands in North Island showed no signs of natural blackwood regeneration away from the planted stands, and rarely within the planted stands (except where there is no livestock grazing), with presence of soil-stored seed banks (C. J. Geldenhuys, personal observation (Nov 2002)). Southern Cape Forests (South Africa)
Acacia melanoxylon is a declared noxious weed species in South Africa. Initial large-scale introduction constrained by the Australian bug, Icerya purchasi, until the bug was controlled by introduction of a ladybird Vedalia cardinalis. Efforts to control invasion of the species were constrained by its rapid spread and its value as timber tree relieving pressure for indigenous timbers. Older stands of this species also nurse the establishment of indigenous forest species and rehabilitation of disturbed natural forest. Planting of blackwood in forest gaps of 0.15 ha within closed forest promoted fast growth of blackwood timber and facilitate natural forest regeneration. Reduced forest disturbance minimize potential for blackwood to become established from soil-sored seed banks. In the medium term a blackwood control program is restricted to areas such as nature reserves where alien invader plants are inherently unacceptable. Two harvesting options for old-growth trees in other areas are followed, depending on the rate at which the old trees are to be removed, and young blackwood is managed to maintain a regular supply of good quality timber without changing the natural forest disturbance regime to cause large canopy gaps. Waikamoi Preserve (United States (USA))
Control of root sprouts escaping the plantations into drainages in Waikomoi should first be controlled. Then all trees near the edges of the plantations should be treated. A 50% Garlon 3A solution on cut stumps were tested and it was recommended that undiluted Garlon 3A and Roundup should be tested. Production of seed and recruitment from seed should be monitored. If fruiting trees are located in Waikomoi, a quick examination of the soil seed bank for the presence of viable seeds may be useful to management. Viability of seed can be tested by germination after soaking seed in boiling water and leaving it overnight. Recruitment from seed can be evaluated by uprooting young plants to determine if they are connected to long, lateral roots. Biocontrol is not feasible or warranted in Hawaii. Soil seed banks may have developed that could be stimulated by disturbance such as fire, resulting and recruitment and spread of this species. Western Cape (South Africa)
Acacia melanoxylon is a declared noxious weed species in South Africa.
Management Resources/Links
1. Daehler, C.C; Denslow, J.S; Ansari, S and Huang-Chi, K., 2004. A Risk-Assessment System for Screening Out Invasive Pest Plants from Hawaii and Other Pacific Islands. Conservation Biology Volume 18 Issue 2 Page 360.
Summary: A study on the use of a screening system to assess proposed plant introductions to Hawaii or other Pacific Islands and to identify high-risk species used in horticulture and forestry which would greatly reduce future pest-plant problems and allow entry of most nonpests. 2. Dr Coert J. Geldenhuys, pers.comm. 6 January 2003.
Summary: Personal communication with Dr Coert J. Geldenhuys. Forestwood cc, P O Box 228, La Montagne, Pretoria 0184, South Africa. Tel/Fax +27 12 803-3277. 4. Geldenhuys, C.J. 1986. Costs and benefits of the Australian Blackwood, Acacia melanoxylon, in South African Forestry. In: I.A.W. Macdonald, F.J. Kruger and A.A. Ferrar (eds) The ecology and management of biological invasions in Southern Africa. Oxford University Press, Cape Town.
p.275?283. 5. Geldenhuys, C.J. 1996. The Blackwood Group System: its relevance for sustainable forest management in the southern Cape. South African Forestry Journal 177, 7-21. 6. Geldenhuys, C.J. 2002. Acacia melanoxylon in South Africa: commercial and conservation issues in resource management. In: Brown, A.G. (ed) 2002. Blackwood management: Learning from New Zealand. International Workshop, Rotorua, New Zealand. p. 28-35. 7. Henderson, L. 1995. Plant invaders of southern Africa. Plant Protection Research Institute Handbook No. 5, Agricultural Research Council, Pretoria, South Africa. 56 p. 8. Julien, M. H. (ed.) 1992. Biological control of weeds: a world catalogue of agents and their target weeds (3rd edition). CAB International, Wallingford, UK. 28pp. 10. Seydack, A.H.W. 2000. Invasion ecology of Australian Blackwood (Acacia melanoxylon) in Southern Cape forests. In: Seydack, A.H.W., Vermeulen, W.J. & Vermeulen, C. (eds). Towards sustainable management based on scientific understanding of natural forests and woodlands. Proceedings of the Natural Forests and Savanna Woodlands Symposium II, Department of Water Affairs & Forestry, Knysna. Pp 40-44. 11. Seydack, A.H.W. 2002. Management options for Australian Blackwood (Acacia melanoxylon) in Southern Cape forests, South Africa. Southern
African Forestry Journal 196, 55-66. 14. Vermeulen, W.J. & Seydack, A.H.W. 2000. Management policy changes for Blackwood (Acacia melanoxylon) in the southern Cape. In: Seydack, A.H.W., Vermeulen, W.J. & Vermeulen, C. (eds). Towards sustainable management based on scientific understanding of natural forests and woodlands. Proceedings of the Natural Forests and Savanna Woodlands Symposium II, Department of Water Affairs & Forestry, Knysna. Pp 45-52. Results Page: 1
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