Pacific Island Ecosystems at Risk (PIER)

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Grevillea robusta
A.Cunn. ex R.Br., Proteaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Evaluate, score: 5 (Go to the risk assessment)

Common name(s): [more details]

English: Australian silky-oak, he oak, she-oak, silk oak, silky oak, silver oak, southern silky-oak

French: chêne d'Australie, grevillaire, grévillée robuste

Hawaiian: ha‘iku ke‘oke‘o

Japanese: shinobu-no-ki

Tongan: ‘oke

Habit:  tree

Description:  "Large evergreen tree 18-30 m high with a straight trunk and moderately spreading crown.  Leaves:  Dark green above, grayish-white or rusty-silky beneath, two-pinnatifid, deeply incised, fern-like, 150-300 mm long, leaflet margins recurved.  Flowers:  Golden-orange, stalked, 20-30 mm long, in terminal, bottlebrush-like sprays 80-150 mm long.  Fruits: Brownish-black, leathery follicles about 20 mm long, containing one or two flat, winged seeds"  (Henderson, 1995; p. 82).

Habitat/ecology:  This large, evergreen tree has been used extensively in reforestation programs. The leaves produce an allelopathic substance that inhibits the establishment of all species, including itself apparently.  It grows well in dry areas between 350-1,600 m (Smith, 1985; p. 191). "Widely planted and a prolific seeder, it is a weed of drier mesic pastures and forests.  Pollen may trigger hay fever"  (Motooka et al., 2003).  In New Caledonia, "arbre planté assez commun à Nouméa et dans l'intérieur" (MacKee, 1994; p. 119).

Propagation:  Wind-dispersed seeds.

Native range:  New South Wales and Queensland, Australia; cultivated elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia (Pacific offshore islands)
Lord Howe Island
Lord Howe Island introduced
Pickard, J. (1984) (p. 207)
Australia (Pacific offshore islands)
Lord Howe Island
Lord Howe Island introduced
invasive
Orchard, Anthony E., ed. (1994) (p. 20)
"Frequently planted as a timber tree throughout tropical and subtropical regions, and often becoming naturalised". Voucher cited: A.C. Beauglehole 5509 (MEL)
Australia (Pacific offshore islands)
Norfolk Islands
Norfolk Island introduced
invasive
Orchard, Anthony E., ed. (1994) (p. 10)
"Frequently planted as a timber tree throughout tropical and subtropical regions, and often becoming naturalised". Voucher cited: W.R. Sykes NI 514 (CHR)
Chile (offshore islands)
Rapa Nui (Easter) Island
Rapa Nui (Easter) Island (Isla de Pasqua) introduced
cultivated
Meyer, Jean-Yves (2008) (pp. 40, 42)
"Nous l’avons vu communément planté autour des zones de pâturages mais sans régénération naturelle visible" (Meyer, 2008; p. 40).
Cook Islands
Southern Cook Islands
‘Atiu Island cultivated
McCormack, Gerald (2013)
Uncommon.
Cook Islands
Southern Cook Islands
Mangaia Island cultivated
McCormack, Gerald (2013)
Uncommon.
Ecuador (Galápagos Islands)
San Cristóbal Group
San Cristóbal Island introduced
cultivated
Charles Darwin Foundation (2008)
French Polynesia
Marquesas Islands
Nuku Hiva (Nukahiva) Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Naturalisée
French Polynesia
Marquesas Islands
Ua Huka (Huahuna, Uahuka) Island introduced
cultivated
Lorence, David H./Wagner, Warren L. (2013)
French Polynesia
Marquesas Islands
Ua Huka (Huahuna, Uahuka) Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2003) (voucher ID: PTBG 40877)
Taxon name on voucher: Grevillea robusta
French Polynesia
Society Islands
Raiatea (Havai) Island introduced
Fosberg, F. R. (1997) (p. 126)
French Polynesia
Society Islands
Taha‘a Island introduced
Fosberg, F. R. (1997) (p. 126)
French Polynesia
Society Islands
Tahiti Island introduced
cultivated
Welsh, S. L. (1998) (p. 224)
Voucher cited: Florence 2448
French Polynesia
Society Islands
Tahiti Island introduced
invasive
cultivated
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Voucher cited: J. Florence 2448 (PAP)
Naturalisée
French Polynesia
Tuamotu Archipelago
Makatea (Ma‘atea) Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Naturalisée
French Polynesia
Austral (Tubuai) Islands
Rapa Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Naturalisée
French Polynesia
Austral (Tubuai) Islands
Rurutu Island introduced
Meyer, Jean-Yves (2000) (p. 94)
"Potential invader".
French Polynesia
Austral (Tubuai) Islands
Rurutu Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Naturalisée
Guam
Guam Island
Guam Island introduced
cultivated
Stone, Benjamin C. (1970) (pp. 259-260)
Voucher cited: Stone 4092 (GUAM)
Guam
Guam Island
Guam Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 63)
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1086)
State of Hawaii
Hawaiian Islands
Kaho‘olawe Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 40)
Single seedling seen and pulled. Voucher cited: Starr, Starr, Higashino & Bruch 040607-1 (BISH)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1086)
State of Hawaii
Hawaiian Islands
Lāna‘i Island introduced
invasive
cultivated
Herbarium Pacificum Staff (1999) (p. 8)
Voucher cited: C. Imada, H. Oppenheimer, J.S. Meidell & C. Gemmill 98-7 (BISH)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1086)
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
cultivated
Oppenheimer, Hank L. (2003) (p. 22)
Voucher cited: Oppenheimer H110129 (BISH, PTBG)
State of Hawaii
Hawaiian Islands
Ni‘ihau Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1086)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1086)
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
cultivated
MacKee, H. S. (1994) (p. 119)
Vouchers cited: Cribs 1300, Le Rat 222, Sarlin 57, MacKee 29471
Niue
Niue
Niue Island introduced
cultivated
Sykes, W. R. (1970) (p. 172)
Single tree. Voucher cited: CHR 168710
Niue
Niue
Niue Island introduced
cultivated
Space, James C./Flynn, Tim (2000) (p. 24)
Samoa
Western Samoa Islands
Upolu Island introduced
cultivated
Space, James C./Flynn, Tim (2002) (p. 9)
Planted tree at watershed nursery, Vailima.
Solomon Islands
Solomon Islands
Solomon Islands introduced
cultivated
Hancock, I. R./Henderson, C. P. (1988) (p. 79)
Tonga
Tongatapu Group
‘Eua Island introduced
cultivated
Space, James C./Flynn, Tim (2001) (p. 7)
Tonga
Tongatapu Group
Tongatapu Island introduced
cultivated
Space, James C./Flynn, Tim (2001) (p. 7)
Tonga
Vava‘u Group
Vava‘u Island introduced
cultivated
Space, James C./Flynn, Tim (2001) (p. 7)
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
New South Wales native
Australian Biological Resources Study (2013)
Australia
Australia (continental)
Queensland native
Australian Biological Resources Study (2013)
China
China
Hong Kong introduced
cultivated
Wu, Te-lin (2001) (p. 157)
Ornamental.
New Zealand
New Zealand
New Zealand (country) introduced
invasive
cultivated
Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 997)
"Rough pasture on scoria of volcanic cone".
Singapore
Singapore
Singapore (Republic of) introduced
cultivated
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 46)
Cultivated only
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia (Indian Ocean offshore islands)
Christmas Island Group
Christmas Island introduced
cultivated
Swarbrick, J. T. (1997) (p. 115)
La Réunion (France)
La Réunion Island
La Réunion Island introduced
invasive
cultivated
Comité français de l'Union Internationale pour la Conservation de la Nature en France (2013)
Utilisé pour la foresterie et planté comme plante ornementale; envahissant principalement dans les milieux perturbés.
French Territory of Mayotte
Mayotte Islands
Mayotte Island introduced
cultivated
Comité français de l'Union Internationale pour la Conservation de la Nature en France (2013)
Potentiellement envahissant.

Comments:  This tree is sometimes used in forestry plantings. It is naturalized in Hawai‘i. Where not present, it should probably not be introduced. New plantings should be limited and existing plantings monitored for invasive behavior.

Naturalized and starting to spread on the island of Rurutu (Austral archipelago, French Polynesia) (Jean-Yves Meyer, pers. com.).

Single tree noted at the watershed nursery in Vailima, Upolu, Samoa (Space & Flynn, 2002).

Control: 

Physical: "Has value as timber. Goats will control silver oak (An Peischel)" (Motooka et al., 2003).

Chemical: "Sensitive to triclopyr ester (2.5% product in diesel oil) applied to frill cuts.  HAVO staff reported control with triclopyr ester at 5% product in diesel oil applied to basal bark (Zimmer, HAVO).  Susceptible to cut-surface and continuous frill applications of picloram and glyphosate and tolerant of 2,4-D and dicamba. Applications of glyphosate and triclopyr to drilled holes in unreplicated demonstrations were very effective" (Motooka et al., 2003).


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This page was created on 1 JAN 1999 and was last updated on 7 MAY 2013.