Grevillea robusta (silky oak)

Pictures

Picture	Title	Caption	Copyright
Title Young tree Caption Young open-grown individual at Tyalgum, New South Wales, Australia. Copyright David Lea/CSIRO Forestry and Forest Products	Young tree	Young open-grown individual at Tyalgum, New South Wales, Australia.	David Lea/CSIRO Forestry and Forest Products
Title Plantation Caption Copyright ICRAF	Plantation		ICRAF
Title Shade tree Caption Tea plantation, Sri Lanka. Copyright Stephen Midgley/CSIRO Forestry and Forest Products	Shade tree	Tea plantation, Sri Lanka.	Stephen Midgley/CSIRO Forestry and Forest Products
Title Shade trees Caption Shade trees planted along the edge of a field of maize in Embu, Kenya. Trees have been pruned to reduce competition with the crop. Copyright Chris Harwood	Shade trees	Shade trees planted along the edge of a field of maize in Embu, Kenya. Trees have been pruned to reduce competition with the crop.	Chris Harwood
Title Field boundary trees Caption Row of trees along the edge of a farmer's field, near Meru, Kenya. The trees have been pruned and pollarded repeatedly to produce firewood and poles, and will eventually be harvested as saw logs. Copyright Chris Harwood	Field boundary trees	Row of trees along the edge of a farmer's field, near Meru, Kenya. The trees have been pruned and pollarded repeatedly to produce firewood and poles, and will eventually be harvested as saw logs.	Chris Harwood
Title Inflorescence Caption Copyright Antoine Kalinganire	Inflorescence		Antoine Kalinganire
Title Line artwork Caption 1. habit 2. leaf 3. inflorescence 4. young flower (stigma retained in bud) 5. tepal with anthers directly attached 6. mature flower (extended style + stigma) 7. fruits 8. winged seed Copyright PROSEA Foundation	Line artwork	1. habit 2. leaf 3. inflorescence 4. young flower (stigma retained in bud) 5. tepal with anthers directly attached 6. mature flower (extended style + stigma) 7. fruits 8. winged seed	PROSEA Foundation

Identity

Preferred Scientific Name

• Grevillea robusta A. Cunn. ex R. Br.

Preferred Common Name

• silky oak

Other Scientific Names

• Grevillea robusta var. compacta auct.
• Grevillea robusta var. forsteri L.H.Bailey
• Grevillea umbratica A.Cunn. ex Meisn
• Grevillea venusta A.Cunn. ex Meisn.

International Common Names

• English: Australian silky-oak; she-oak; silver oak; southern silky-oak
• Spanish: grevillea; pino rojo; roble australiano; roble de pelota; roble sedoso
• French: grevillaire; grévilléa robuste

Local Common Names

• Australia: river oak; silk oak
• Brazil: carvalho-sedoso; grevílea-gigante; grevilha-robusta
• Cuba: roble plateado
• Dominican Republic: helecho
• Germany: Silberstrauch, Australischer
• Hawaii: haiku-keokeo; oka-kilika
• Honduras: gravilea
• India: silver oak
• Italy: grevillea
• Java: salamandar
• Puerto Rico: roble de seda
• Tanzania: mgrivea
• USA: lacewood

EPPO code

• GRERO (Grevillea robusta)

Trade name

• southern silky oak

Summary of Invasiveness

G. robusta is a tree which is an effective colonizer and has demonstrated invasive behaviour in Australia (New South Wales), New Zealand, French Polynesia, Jamaica, Zimbabwe, and notably in South Africa and the United States (i.e., Hawaii). Contributing to its behaviour is likely to be its early and prolific seed producing habit, and the production of potentially allelopathic compounds. In South Africa, G. robusta has been declared a category 3 invader (Henderson, 2001). It is also invasive in Hawaii (Holm et al., 1979; Cronk and Fuller, 1995; Space and Flynn, 2001), a common weed in Micronesia (Space and Falanruw, 1999) and cultivated in Niue (Space and Flynn, 2000). It seeds heavily and regenerates strongly after disturbance in rainforests and along riverbanks. Several years ago, Binggeli (1999) classified G. robusta as a moderately invasive species: currently, it is listed as invasive and potentially invasive in many countries in South America, Africa, Asia, and on many islands in the West Indies and the Indian and Pacific Oceans (Harwood, 1997; Kairo et al., 2003; Oviedo Prieto et al., 2012; PIER, 2015; PROTA, 2015).  

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Proteales
•                         Family: Proteaceae
•                             Genus: Grevillea
•                                 Species: Grevillea robusta

Notes on Taxonomy and Nomenclature

The family Proteaceae includes 80 genera and 1600 species of shrubs and trees distributed principally in the southern hemisphere, especially across Australia and South Africa. There are about 515 species in the genus Grevillea (family Proteaceae), most of which are endemic to Australia (Stevens, 2012). Grevillea robusta was described by Alan Cunningham, and the name was published in 1830 in the Supplementum Primum to Robert Brown's Prodromus Florae Novae Hollandiae. The specific epithet is derived from the Latin robustus - hard, strong, robust, in reference to the large size of this species in a genus where many species are shrubs. It has no recognized subspecies or varieties, and no hybrids with other species have been recorded (McGillivray and Makinson, 1993).

Description

G. robosta is an erect, single-stemmed tree typically reaching 20-30 m tall and 80 cm in stem diameter. The crown is conical and symmetrical with major branches spaced at intervals of about 1 m and projecting upwards at an angle of 45°. Bark on the trunk is dark grey and furrowed into a lace-like pattern. G. robusta is described and illustrated by McGillivray and Makinson (1993), Boland et al. (1984), and Harwood (1997). Proteoid roots (sections of the secondary roots which develop as dense cylindrical clusters of rootlets) develop in conditions of low phosphorus availability, and are thought to increase the plant's ability to take up nutrients (Skene et al., 1996). Young branchlets are angular and ridged, subsericeous to tomentose but glabrous on older growth. The fern-like foliage of this species is very distinctive. Leaves are 10-34 cm long, 9-15 cm wide, variably pinnate to bipinnate, with a glabrous green upper surface and subsericeous silvery under-surface. Petioles are 1.5-6.5 cm long. The species is semi-deciduous in its natural range, being almost leafless shortly before flowering. The flowers are grouped into compound racemose inflorescences (conflorescences, after Johnson and Briggs (1975)), which themselves are grouped into panicles of one to six conflorescences, borne on older wood. The bright orange flowers, about 2 cm long, are borne in numerous pairs along the flower spikes, on pedicels 1.5 cm long. The perianth consists of 4 narrow tepals, 0.6-1 cm long, with the concave summit of each tepal holding a small anther 0.1 cm long. The ovary surmounts a gynophore 0.2-0.3 cm long. Fruits are two-seeded follicles 2 cm in length, with a slender persistent style. Seeds are winged, 13-19 mm long, 8-10 mm wide, 0.8-0.9 mm thick, with a papery wing around the brown, ovate central seed body.

Plant Type

Distribution

G. robusta is native to northern New South Wales and southern Queensland, Australia, where it occurs from the east coast to as far west as the Bunya Mountains, Queensland, some 160 km inland. The north-south range of the species is some 470 km, from the Guy Fawkes and Orara Rivers (tributaries of the Clarence River in New South Wales, 30°10'S) to just north of Gympie, Queensland (25°50'S). It is found across a wide range of altitudes from sea level to mountaintop occurrences at 1120 m in the Bunya Mountains (Harwood, 1992a). Outside its native distribution range, this species can be found naturalized in tropical Asia, Africa, America and the West Indies (see distribution table for details; Harwood, 1997; Acevedo-Rodriguez and Strong, 2012; PIER, 2015; PROTA, 2015). 

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

G. robusta has been introduced to other parts of Australia outside its native distribution range, and is now regarded as invasive around Sydney and is a known weed in the Blue Mountains of New South Wales (BMCS, 2002). It has also been introduced to warm temperate, subtropical and tropical highland regions around the world commencing in the mid to late 1800s, and it is now widely planted in India, Sri Lanka, Central and South America and many countries in Africa (Harwood, 1989). It performs poorly in lowland tropical environments. In Hawaii, it was introduced in 1880 from Australia (Motooka et al., 2003). In the West Indies, G. robusta appears in herbarium collection made in 1899 in Guadeloupe, 1916 in Puerto Rico, 1928 in Dominican Republic and 1932 in Jamaica (US National Herbarium).  

Risk of Introduction

 The risk of introduction of G. robusta is moderate to high. This species has been widely planted in warm temperate, subtropical and tropical regions of the world and it is a prolific seed producer. It behaves as a weed in drier mesic pastures, disturbed areas and forests and it can be found naturalized principally in areas near cultivation (Harwood et al., 1997; ISSG, 2015; PROTA, 2015). 

Habitat

In its native range, G. robusta is commonly found in small, discontinuous stands along the banks of rivers and streams, usually within 30 m of the water's edge, in areas with generally moderate to good soil fertility and water availability. G. robusta is vulnerable to fire and hence is excluded from the fire-prone Eucalyptus forests and grasslands that occupy much of its natural range. Habitats invaded by this species in South Africa include forest edges, coastal forests, disturbed sites, savannah and riparian areas (Henderson, 2001). It is very popular in agroforestry systems and often planted to provide shade for tea and coffee plantations (Harwood et al., 1997).

Habitat List

Biology and Ecology

Genetics

The chromosome number reported for G. robusta is 2n = 20.

No records of hybrids between G. robusta and other species of Grevillea have been published. Isozyme studies of natural populations and land races (Harwood et al., 1997) established that the species has a moderate level of allozyme heterozygosity in natural populations. The genetic diversity of individual populations varied little, and did not appear to be related to their ecological characteristics (araucarian vine forest or riverine habitat types) or their geographic locations. Between-population differences accounted for 17.9% of the total genetic variation. It appears that genetic exchange between populations has been maintained, despite the pattern of natural distribution in small, separated populations. African land races of G. robusta are descended from initial introductions in the late 1800s and early 1900s and have developed in different countries in partial or total isolation from one another, and mean heterozygosity and other genetic diversity measures were substantially lower for the African land races than for the natural populations. The complete absence of a common allele in the two Madagascar populations suggested that these populations were derived from a very narrow genetic base. Provenance-progeny trials testing seed collections from across the natural range have recently been established in several countries including Australia, Kenya and Rwanda.

Physiology and Phenology

Flowering commences in October in lowland occurrences in the native range, and seed is mature by the end of December. At high elevations, flowering and seed production occur 4-6 weeks later (Harwood, 1992a). In the equatorial highlands where rainfall distributions are bimodal, flowering is much less synchronized. In western Kenya, for example, there are two main flowering peaks in March-May and August-October, with some trees flowering throughout the year (Kalinganire et al., 1996). In its native range, the species is partly deciduous, losing much of its canopy in the dry spring months (September-October) and recovering in early summer. In the equatorial highlands there is no clear seasonal pattern of foliage loss.

Reproductive Biology

Under favourable conditions, flowering and seed production of G. robusta commence at age 2-3 years (Kalinganire et al., 1996). In subtropical and warm temperate latitudes, first flowering may occur at 4-6 years (Swain 1928). Flowering in the native range occurs for a few weeks in October-November but in equatorial latitudes the species may flower at any time of year and in Jakarta, Indonesia, it does not flower (World Agroforestry Centre, 2002). There are about 40,000 viable seeds/kg. The species seeds heavily and regenerates strongly after site disturbance in rainforests and along riverbanks.

The breeding system in natural populations was found to be highly outcrossing in isozyme studies of progeny arrays (Harwood et al., 1992). Multi-locus estimates of outcrossing rates of 0.97 and 0.86 were obtained for two natural populations. Observations and experimental studies in a planted stand in western Kenya (Kalinganire et al., 1996) confirmed that the species is fully outcrossing and self-incompatible, and that nectivorous birds are the principal pollinating agents in Kenya, as was found in Australia (Brough, 1933). According to the World Agroforestry Centre (2002) pollinating agents also include honeybees and tree-living marsupials (Phanlangeridae) but Kalinganire et al. (2001) report that ants and bees are nectar robbers that rarely come into contact with the stigmas. The period from the start of inflorescence development to anthesis is about 40 days. Stigmas become receptive 1 day after anthesis, and the period from fertilization to fruit maturity is about 60 days. Hot, dry weather stimulates seed release once the fruits are mature. G. robusta may also vegetatively reproduce by root suckering (World Agroforestry Centre, 2002).

Environmental Requirements

The distribution is in the warm humid to warm sub-humid climatic zones. Climatic analysis of the natural occurrences and locations where the species is successfully grown as an exotic has been carried out by Harwood and Booth (1992) and a modified description of climatic requirements was prepared by CSIRO (Booth and Jovanovic, 2000). Within its natural distribution range, climate varies widely because of the substantial altitudinal range (0-2500 m) and the rainfall gradients created by prevailing weather systems interacting with rugged topography. Mean annual rainfall is in the range 700-2400 mm, but droughts of 6 months or longer will cause death or damage to established trees, although towards the hotter extremes of the tolerated temperature range, the dry season should be no longer than 4 months for good growth.. It has some resistance to frost, as during the winter months in temperate latitudes, G. robusta can survive temperatures down to -8°C with little or no damage, but milder frosts of only -2°C or so will cause damage during the growing season.

While it occurs naturally along riverbanks and will survive short periods of flooding by moving water, G. robusta will not grow on poorly-drained, swampy sites where waterlogging occurs for more than a few days at a time. The species is more common on rather fertile soils such as those derived from river alluvia or basalts but will grow on shallower, less fertile soils derived from sedimentary material. Best growth is obtained on sandy loam, loam and clay loam soils and it performs poorly on heavy clays. The pH range for good growth is around 4.5 to 7.5. In highly acid soils, symptoms of boron deficiency (Smith, 1960) and manganese toxicity (Child and Smith, 1960) have been observed. While the species is frequently planted as a windbreak around plantations of food and cash crops, it cannot withstand severe gales or persistent strong winds without damage to the branches. Even low-intensity ground fires will kill seedlings and young trees.

Associations

G. robusta is present in riverine gallery rainforest of the Castanospermum australe (black bean) alliance, the natural vegetation along larger Australian rivers. The frequency of mature trees has, however, been reduced across much of the natural range as a result of past logging and land clearance. G. robusta is also associated with river she-oak (Casuarina cunninghamiana) along smaller streams where rainforest has not developed. The second major habitat type for the species is the Araucarian vine forests and vine thickets dominated by Araucaria cunninghamii. These forests contain rainforest elements but are subject to occasional fires. The species is not known to form symbiotic associations with soil bacteria or mycorrhizal fungi, although it develops proteoid roots that are believed to enhance nutrient uptake. 

Latitude/Altitude

Air Temperature

Rainfall

Rain Regime

Soil Tolerances

Soil drainage

• free

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• light
• medium

Notes on Natural Enemies

In the humid tropical lowlands and other regions with high humidity, G. robusta is vulnerable to attack by fungal diseases such as Botryosphaeria dothidea in Guatemala (Schieber and Zentmeyer, 1978) and Corticium salmonicolor [Erythricium salmonicolor] in Karnataka, India (Nayar, 1987). Pathogenic fungi such as a Amphichaeta grevilleae [Seimatosporium grevilleae] (Loos, 1950; Venkataramani, 1954), Cercospora sp. (Chiddawar, 1956) and Phyllosticta sp. (Rao, 1961) have been observed to cause considerable damage to leaves and stems of young plants in Sri Lanka. In lowland environments in the Caribbean, G. robusta is severely attacked by the scale insect Asterolecanium pustulans (Martorell, 1940), effectively precluding its use there. Attack by termites can be a problem when the species is planted on dry sites in Africa.

Means of Movement and Dispersal

The seeds of G. robusta are dispersed by wind (Smith, 1998). G. robusta has gained widespread popularity in warm temperate, subtropical and tropical highland regions of many countries, originally as a shade tree for tea and coffee and now as an agroforestry tree for small farms (Harwood, 1989) and intentional introduction is the principal means of long-distance dispersal.

Pathway Causes

Pathway Vectors

Impact Summary

Economic Impact

Its use as tea shade has been largely discontinued in Kenya and Rwanda because of the risk of Armillaria and other root pathogens spreading from dead G. robusta roots to those of the tea plants (Tea Research Institute of East Africa, 1969).

Environmental Impact

G. robusta drops much leaf and fruit litter (Gilman and Watson, 1993). Its leaves produce an allelopathic substance that inhibits the establishment and development of native species. G. robusta also causes changes in patterns of nutrient cycling (ISSG, 2015).

Biodiversity

Smith (1998) reports allelopathic effects that restrict the growth of other plants including other individuals of G. robusta. Webb et al. (1967) considered that an auto-allelopathic compound associated with the living roots of G. robusta was responsible for the poor performance of plantations in Australia. The good growth of many successful plantations and woodlots in Africa suggests that in most plantations such an effect is minor, if present at all. Henderson (2001) regarded G. robusta as a potential transformer of habitats. 

Social Impact

The sap of G. robusta is an irritant to skin and eyelids (Henderson, 2001) and its pollen may trigger hay fever (Motooka et al., 2003). 

Risk and Impact Factors

Impact mechanisms

• Allelopathic
• Competition - shading
• Pest and disease transmission

Impact outcomes

• Altered trophic level
• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Modification of nutrient regime
• Modification of successional patterns
• Negatively impacts human health
• Reduced native biodiversity

Invasiveness

• Has high reproductive potential
• Highly adaptable to different environments
• Highly mobile locally
• Invasive in its native range
• Long lived
• Proved invasive outside its native range
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc

Likelihood of entry/control

• Highly likely to be transported internationally deliberately

Uses

G. robusta is a common element in agroforestry and forestry applications, and is one of the most important trees for agroforestry in the tropical highlands of East and central Africa (Harwood, 1992b). It is commonly planted as a boundary tree around the perimeter of small farms, in a single row at 2-2.5 m spacing. It is also planted in rows between small fields, and as scattered individuals over crops such as coffee and maize (Spiers and Stewart, 1992). G. robusta has been planted as a component of contour rows in a number of farming systems that aim to conserve soil on sloping lands in the tropical highlands (e.g. Neumann, 1983). The use of the leaves as a mulch is frequently advocated and practised, and studies have shown that this can reduce soil losses on sloping land (Omoro and Nair, 1993).

The dense, brilliant golden-yellow or orange flower heads, attractive silver, fern-like leaves and symmetrical crown encourage widespread and increasing use of the species as an ornamental. It is used in many tropical and subtropical countries for park and roadside plantings. In the UK and Europe it is commonly available as an indoor plant. In Australia, other Grevillea species and interspecific hybrids are commonly grafted onto rootstocks of G. robusta to produce ornamental planting stock. This practice takes advantage of the resistance of the root system of G. robusta to Phytophthora cinnamomi and its non-susceptibility to phosphorus toxicity, which is a problem for most other Grevillea species (Burke, 1983).

From the late 1800s onwards, G. robusta has been planted extensively as high shade for tea and coffee plantations, and this use continues in many countries. The trees are often pollarded to produce a spreading crown, and have a typical working life of 40-50 years before they become senescent and must be replaced (Rao 1961). Shade trees of G. robusta provided effective protection against frost that caused extensive damage to open-grown coffee plants in southern Brazil at planting densities of 71 and 119 trees per hectare, but not at 26, 34 and 48 trees per hectare (Baggio et al., 1997), and the economic productivity of coffee and G. robusta wood at 34, 48 and 71 trees per hectare was greater than that of coffee in unshaded plantations. Only at 119 trees per hectare was there a significant (15%) reduction of total coffee production to age 10 years, relative to unshaded stands.

The sawn timber is of medium strength and is used for furniture, packing cases, flooring, panelling, plywood and the manufacture of small wooden items such as pencils (Bolza and Keating, 1972; Skolmen, 1974). The wood produces short-fibre pulp of acceptable quality (Ghosh, 1972) but has not been used for pulp production on a commercial scale. Poles are used for house construction, scaffolding and rafters in rural areas (Spiers and Stewart, 1992). The branches and twigs are used for firewood and charcoal (Mbuya et al., 1994).

In addition to their use as a soil mulch, the leaves of G. robusta are used by some farmers in the Embu district of Kenya as a fodder supplement for cattle in the dry season when other fodder sources are scarce (Spiers and Stewart, 1992). They are also used as bedding in livestock stalls. The leaves contain a number of useful chemical compounds, in particular rutin which has pharmacological applications (Cannon et al., 1973). However, the rutin concentration of 0.6% of leaf dry weight is too low to be of commercial value. The gum produced from the wood of trees that are stressed or wounded may have commercial value (Anderson and de Pinto, 1982).

Uses List

Animal feed, fodder, forage

• Fodder/animal feed

Environmental

• Agroforestry
• Boundary, barrier or support
• Erosion control or dune stabilization
• Graft stock
• Shade and shelter
• Windbreak

Fuels

• Charcoal
• Fuelwood

General

• Ornamental

Human food and beverage

• Honey/honey flora

Materials

• Carved material
• Fibre
• Gum/resin
• Miscellaneous materials
• Wood/timber

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical

Wood Products

Prevention and Control

G. robusta is vulnerable to fire, which may be used as a means of control. Also, grazing with goats can contribute to the control of G. robusta (PIER, 2002). Herbicides such as triclopyr ester, picloram and glyphosate may be used against G. robusta, with modes of application including basal bark applications, cut surface, frill cut and continuous frill techniques, though it appears to be resistant to 2,4-D and dicamba (PIER, 2002). Smith (1998) reports that biological control has not been investigated on Hawaii because of conflicts with forestry and farming industries.

References

Acevedo-Rodríguez P, Strong MT, 2012. Catalogue of the Seed Plants of the West Indies. Smithsonian Contributions to Botany, 98:1192 pp. Washington DC, USA: Smithsonian Institution. http://botany.si.edu/Antilles/WestIndies/catalog.htm

Akyeampong E, Hitimana L, Franzel S, Munyemana PC, 1995. The agronomic and economic performance of banana, bean and tree intercropping in the highlands of Burundi: an interim assessment. Agroforestry Systems, 31(3):199-210.

Anderson DMW, de Pinto GL, 1982. Gum exudates from the genus Grevillea (Proteaceae). Carbohydrate Polymers, 2:19-24.

Anon, 2003. Alien invasive plant species of Jamaica. Clearing house mechanism. http://www.jamaicachm.org.jm/aliens_i_pl.htm.

Baggio AJ, Caramori, PH, Androcioli Filho A, Montoya, L, 1997. Productivity of southern Brazilian coffee plantations shaded by different stockings of Grevillea robusta. Agroforestry Systems, 37:111-120.

Binggeli P, 1999. Invasive woody plants. http://members.lycos.co.uk/WoodyPlantEcology/invasive/index.html.

BMCS, 2002. BMCS Submission to Draft LEP, 2002. Schedule 6, Weeds of the Blue Mountains. Blue Mountains Conservation Society, Australia. http://www.bluemountains.org.au/conservation/DLEP2002/bmcssi2.shtml.

Boland DJ, Brooker MIH, Chippendale GM, Hall N, Hyland BPM, Johnston RD, Kleinig DA, Turner JD, 1984. Forest trees of Australia. 4th ed. Melbourne, Australia:Thomas Nelson and CSIRO. xvi + 687 pp.; 77 ref.

Bolza E, Keating WG, 1972. African timbers - the properties, uses and characteristics of 700 species. Melbourne, Australia: CSIRO Division of Building Research.

Booth TH, Jovanovic T, 2000. Improving descriptions of climatic requirements in the CABI Forestry Compendium. A report for the Australian Centre for International Agricultural Research. CSIRO - Forestry and Forest Products, Client Report No. 758.

Brough, P, 1933. The life history of Grevillea robusta Cunn. Proceedings of the Linnaean Society of New South Wales, 58:33-73.

Burke D, 1983. Growing grevilleas. Sydney, Australia: Kangaroo Press.

Buss CM, 2002. The potential threat of invasive tree species in Botswana. Department of Crop Production and Forestry, Ministry of Agriculture, Government of Botswana, 40 pp.

Cannon JR, Chow PW, Fuller MW, Hamilton BH, Metcalf BW, Power AJ, 1973. Phenolic constituents of [the leaves of] Grevillea robusta (Proteaceae). The structure of robustol, a novel macrocyclic phenol. Australian Journal of Chemistry, 26(10):2257-2275; 50 ref.

Charles Darwin Foundation, 2008. Database inventory of introduced plant species in the rural and urban zones of Galapagos. Galapagos, Ecuador: Charles Darwin Foundation.

Chiddarwar PP, 1956. A new species of Cercospora on an economic host. Current Science, 25(8):267.

Child R, Smith AN, 1960. Manganese toxicity in Grevillea robusta. Nature, Lond. 186 (4730):1067; 1 ref.

Chong KY, Tan HTW, Corlett RT, 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Singapore: Raffles Museum of Biodiversity Research, National University of Singapore, 273 pp. http://lkcnhm.nus.edu.sg/nus/pdf/PUBLICATION/LKCNH%20Museum%20Books/LKCNHM%20Books/flora_of_singapore_tc.pdf

Cronk QCB, Fuller JL, 1995. Plant invaders: the threat to natural ecosystems. London, UK; Chapman & Hall Ltd, xiv + 241 pp.

DAISIE, 2015. Delivering Alien Invasive Species Inventories for Europe. European Invasive Alien Species Gateway. www.europe-aliens.org/default.do

Faridah Hanum I, Maesen LJG van der, eds., 1997. Plant resources of southeast Asia. No. 11. Auxillary plants. Leiden, Netherlands: Backhuys.

Ghosh KL, 1972. Pulping characteristics of Silver Oak [Grevillea robusta]: unbleached kraft paper for wrapping and packing purposes. Indian Pulp and Paper, 26(11):185-193; 12 ref.

Gilman GF, Watson DG, 1993. Grevillea robusta: silk-oak. University of Florida Extension. Fact Sheet ENH-444. http://edis.ifas.ufl.edu/pdffiles/ST/ST28500.pdf.

Harwood CE, 1989. Grevillea robusta: an annotated bibliography. Nairobi, Kenya: International Council for Research in Agroforestry (ICRAF); 123 pp.; 224 ref.

Harwood CE, 1992. Grevillea robusta in agroforestry and forestry: proceedings of an international workshop. Nairobi, Kenya: International Council for Research in Agroforestry (ICRAF): 190 pp.

Harwood CE, 1992. Natural distribution and ecology of Grevillea robusta. In: Harwood CE, ed. Grevillea robusta in Agroforestry and Forestry: Proceedings of an International Workshop. Nairobi, Kenya: International Council for Research in Agroforestry (ICRAF); 21-28.

Harwood CE, 1997. Grevillea robusta A. Cunn. ex R. Br. In: Ibrahim FH, van der Maesen LJG, eds. Plant Resources of South-East Asia (PROSEA). No 11, Auxiliary Plants. The Netherlands: Backhuys Publishers; 151-155.

Harwood CE, Bell JC, Moran GF, 1992. Isozyme studies on the breeding system and genetic variation in Grevillea robusta. In: Harwood CE, ed. Grevillea robusta in Agroforestry and Forestry: Proceedings of an International Workshop. Nairobi, Kenya: International Council for Research in Agroforestry (ICRAF): 165-176.

Harwood CE, Booth TH, 1992. Status of Grevillea robusta in forestry and agroforestry. In: Harwood CE, ed. Grevillea robusta in Agroforestry and Forestry: Proceedings of an International Workshop. Nairobi, Kenya: International Council for Research in Agroforestry (ICRAF): 9-16.

Harwood CE, Moran GF, Bell JC, 1997. Genetic differentiation in natural provenances of Grevillea robusta. Australian Journal of Botany, 45:669-678.

Harwood CE, Owino F, 1992. Design of a genetic improvement strategy for Grevillea robusta. In: Harwood CE, ed. Grevillea robusta in Agroforestry and Forestry: Proceedings of an International Workshop. Nairobi, Kenya: International Council for Research in Agroforestry (ICRAF): 141-150.

Henderson L, 2001. Alien Weeds and Invasive Plants. Plant Protection Research Institute Handbook No. 12. Cape Town, South Africa: Paarl Printers.

Holm LG, Pancho JV, Herberger JP, Plucknett DL, 1979. A geographical atlas of world weeds. New York, USA: John Wiley and Sons, 391 pp.

Howard SB, Ong CK, Black CR, 1996. Using sap flow gauges to quantify water uptake by tree roots from beneath the crop rooting zone in agroforestry systems. Agroforestry Systems, 35:15-29.

I3N-Argentina, 2014. Invasive alien species database, I3N Argentina. Bahía Blanca, Argentina: I3N Argentina - Universidad Nacional del Sur. www.inbiar.org.ar

I3N-Brasil, 2014. Base de dados nacional de espécies exóticas invasora (National database of exotic invasive species). Florianópolis - SC, Brazil: I3N Brasil, Instituto Hórus de Desenvolvimento e Conservação Ambiental. http://i3n.institutohorus.org.br

IABIN, 2003. Preliminary List of Alien Invasive Species occuring in Jamaica. The United States Node of the Inter-American Biodiversity Information Net (IABIN). http://www.iabin-us.org/projects/i3n/i3n_documents/catalogs/catalog_jamaica.html.

ISSG, 2015. Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species Survival Commission. http://www.issg.org/database/welcome/

Johnson LAS, Briggs BG, 1975. On the Proteaceae - the evolution and classification of a southern family. Botanical Journal of the Linnean Society, 70(2):83-182.

Jones L, 1967. Effect of storage at various moisture contents and temperatures on seed germination of Silk Oak, Australian Pine and Eucalyptus spp. Research Note No. SE-83. U.S. For. Serv. Res. Note. South East Forest Experimental Station; pp. 4.

Kairo M, Ali B, Cheesman O, Haysom K, Murphy S, 2003. Invasive species threats in the Caribbean region. Report to the Nature Conservancy. Curepe, Trinidad and Tobago: CAB International, 132 pp. http://www.issg.org/database/species/reference_files/Kairo%20et%20al,%202003.pdf

Kalinganire A, 1996. Performance of Grevillea robusta in plantations and on farms under varying environmental conditions in Rwanda. Forest Ecology and Management, 80(1-3):279-285; 20 ref.

Kalinganire A, Hall JB, 1993. Growth and biomass production of young Grevillea robusta provenances in Rwanda. Forest Ecology and Management, 62(1-4):73-84; 25 ref.

Kalinganire A, Harwood CE, Simons AJ, Slee MU, 1996. Reproductive ecology of Grevillea robusta in western Kenya. In: Dieters MJ, Matheson AC, Nikles DG, Harwood CE, Walker SM, eds. Tree Improvement for Sustainable Tropical Forestry. Proc. QFRI-IUFRO Conf., Caloundra, Queensland, Australia, 27 Oct - 1 Nov 1996; 238-243. Gympie:Queensland Forestry Research Institute, 238-243.

Kalinganire A, Harwood CE, Slee MU, Simons AJ, 2001. Pollination and fruit-set of Grevillea robusta in western Kenya. Austral Ecology, 26:637-648.

Loos CA, 1950. Amphichaeta grevilleae n.sp., on Grevillea robusta seedlings. Trans. Brit. mycol. Soc. 33 (1/2):40-2. [Tea Research Institute of Ceylon.].

Martorell LF, 1940. Some notes on forest entomology. Carib. For., 1(2):31-32. [Agricultural Exp. Sta., Rio Piedras, Puerto Rico.].

Mayne WW, 1947. Coffee planting in South India: an example of conservation agriculture in the tropics. Trop. Agriculture, Trin. 24 (4/6) (54-6).

Mbuya LP, Msanga HP, Ruffo CK, Birnie A, Tengnas B, 1994. Useful trees and shrubs for Tanzania: identification, propagation and management for agricultural and pastoral communities. Technical Handbook: Regional Soil Conservation Unit, Nairobi.

McGillivray DM, Makinson RO, 1993. Grevillea, Proteaceae, a taxonomic revision. Melbourne, Australia: Melbourne University Press.

Meyer JY, 2008. Report of the expert mission to Rapa Nui, 2-11 June 2008. Strategic action plan to control invasive alien plants on Rapa Nui (Easter Island) (Rapport de mission d'expertise a Rapa Nui du 02 au 11 Juin 2008: Plan d'action strategique pour lutter contre les plantes introduites envahissantes sur Rapa Nui (Île de pâques)). Papeete, Tahiti: Délégation à la Recherche, Ministère de l'Education, l'Enseignement supérieur et la Recherche, 62 pp. http://www.li-an.fr/jyves/Meyer_2008_Rapport_Expertise_Rapa_Nui.pdf

Morales JF, 2014. Proteaceae. Monographs in Systematic Botany from the Missouri Botanical Garden, 129:394-400. [Manual de Plantas de Costa Rica. Vol. VII.]

Motooka P, Castro L, Nelson D, Nagai G, Ching L, 2003. Weeds of Hawaii's Pastures and Natural Areas; an identification and management guide. Manoa, Hawaii, USA: College of Tropical Agriculture and Human Resources, University of Hawaii.

Muchiri MN, 2004. Grevillea robusta in agroforestry systems in Kenya. Journal of Tropical Forest Science, 16(4):396-401.

Nayar R, 1987. Die back in Grevillea robusta A. Cunn. Myforest, 23(2):89-93

Nelson RE, Schubert TH, 1976. Adaptability of selected tree species planted in Hawaii forests. USDA Forest Service Resource Bulletin, Pacific Southwest Forest and Range Experiment Station, No. PSW-14, 22 pp.

Neumann IF, 1983. Use of trees in smallholder agriculture in tropical highlands. In: Lockertz W, ed. Environmentally Sound Agriculture. New York, Praeger: 351-374.

Nyoka BI, 2002. The status of invasive alien forest trees species in Southern Africa. Forest Resources Division, FAO, Rome. http://www.fao.org/DOCREP/005/Y4341E/Y4341EO4.htm.

Okorio J, Byenkya S, Wajja N, Peden D, 1994. Comparative performance of seventeen upperstorey tree species associated with crops in the highlands of Uganda. Agroforestry Systems, 26(3):185-203; 37 ref.

Omoro LMA, Nair PKR, 1993. Effects of mulching with multipurpose-tree prunings on soil and water run-off under semi-arid conditions in Kenya. Agroforestry Systems, 22(3):225-239; 35 ref.

Orchard AE, 1994. Flora of Australia. Vol. 49, Oceanic islands 1. Canberra, Australia: Australian Government Publishing Service.

Orwa C, Mutua A, Kindt R, Jamnadass R, Simons A, 2009. Agroforestree Database: a tree reference and selection guide version 4.0. World Agroforestry Centre. http://www.worldagroforestry.org/af/treedb/

Oviedo Prieto R, Herrera Oliver P, Caluff MG, et al., 2012. National list of invasive and potentially invasive plants in the Republic of Cuba - 2011. (Lista nacional de especies de plantas invasoras y potencialmente invasoras en la República de Cuba - 2011). Bissea: Boletín sobre Conservación de Plantas del Jardín Botánico Nacional de Cuba, 6(Special Issue 1):22-96.

Pandey D, 1987. Yield models of plantations in the tropics. Unasylva, 39(3-4):74-75; 7 ref.

PIER, 2002. Plant threats to Pacific ecosystems. Pacific Island Ecosystems at Risk (PIER). http://www.hear.org/pier/threats.htm.

PIER, 2015. Pacific Islands Ecosystems at Risk. Honolulu, USA: HEAR, University of Hawaii. http://www.hear.org/pier/index.html

Poulsen G, 1983. Using farm trees for fuelwood. Unasylva, 35(141):26-29; 2 pl.

PROTA, 2015. PROTA4U web database. Grubben GJH, Denton OA, eds. Wageningen, Netherlands: Plant Resources of Tropical Africa. http://www.prota4u.info

Rajasekaran P, 1994. Production of clonal plantlets of Grevillea robusta in in vitro culture via axillary bud activation. Plant Cell, Tissue and Organ Culture, 39(3):277-279; 10 ref.

Rao YRA, 1961. Shade trees for Coffee. II. Grevillea robusta A. Cunn. Indian Coffee, Bangalore 25 (11), (329-32 + 1 set of drawings). 15 refs.

Schieber E, Zentmyer GA, 1978. An important canker disease of grevillea in Guatamala. Plant Disease Reporter, 62(10):923-924

Skene KR, Kierans M, Sprent JI, Raven JA, 1996. Structural aspects of cluster root development and their possible significance for nutrient acquisition in Grevillea robusta (Proteaceae). Annals of Botany, 77(5):443-451; 47 ref.

Skolmen RG, 1974. Some woods of Hawaii - properties and uses of 16 commercial species. USDA Forest Service General Technical Report, Pacific Southwest Forest and Range Experiment Station, No. PSW-8, 30 pp.

Smith AN, 1960. Boron deficiency in Grevillea robusta. Nature, Lond. 186 (4729):987; 2 refs.

Smith CW, 1998. Hawaiian Alien Plant Studies. Grevillea robusta A. Cunn. ex R. Br. University of Hawaii Botany Department. http://www.botany.hawaii.edu/faculty/cw_smith/gre_rob.htm.

Sosef MSM, Hong LT, Prawirohatmodjo S, eds, 1998. Plant resources of southeast Asia. Timber trees: lesser-known timbers. Leiden, The Netherlands: Backhuys Publishers, 5(3).

Space JC, Falanruw M, 1999. Observations on invasive plant species in Micronesia. Honolulu, Hawaii: USDA Forest Service, 32 pp.

Space JC, Flynn T, 2000. Report to the Government of Niue on invasive plant species of environmental concern. USDA Forest Service, Honolulu, 34.

Space JC, Flynn T, 2001. Report to the Kingdom of Tonga on invasive plant species of environmental concern. Institute of Pacific Islands Forestry, Honolulu, Hawaii, USA: USDA Forest Service.

Spiers N, Stewart M, 1992. Use of G. robusta in Embu and Meru districts of Kenya. In:Harwood CE, ed. Grevillea robusta in Agroforestry and Forestry:Proceedings of an International workshop. Nairobi, Kenya: ICRAF: 37-48.

Stein BA, 2001. Proteaceae. Monographs in Systematic Botany from the Missouri Botanical Garden, 85(3):2185-2186. [Flora de Nicaragua.]

Stevens PF, 2012. Angiosperm Phylogeny Website. http://www.mobot.org/MOBOT/research/APweb/

Sun D, Dickinson GR, Bragg AL, 1995. Morphological variations between twelve provenances of Grevillea robusta planted in north-east Queensland. Australian Forestry, 58(3):129-134; 12 ref.

Swain EHF, 1928. A silvicultural note on southern silky oak. Queensland Forest Service Bulletin No. 9.

Swarbrick JT, 1997. Environmental weeds and exotic plants on Christmas Island, Indian Ocean. Report to Parks Australia. J.T. Swarbrick, Weed Science Consultancy, 131 pp.

Tea Research Institute of East Africa, 1969. Tea Growers Handbook 1969. Tea Boards of Kenya, Tanganyika and Uganda.

USDA-NRCS, 2004. The PLANTS Database, Version 3.5. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov.

Venkataramani KS, 1954. A leaf disease of nursery plants of the Silver Oak. Planters' Chronicle, Coonoor 49 (21):570-1; 4 refs.

Webb CJ, Sykes WR, Garnock-Jones PJ, 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Christchurch, New Zealand: Botany Division, DSIR, 1365 pp.

Webb LJ, Tracey JG, Haydock KP, 1967. A factor toxic to seedlings of the same species associated with living roots of the non-gregarious subtropical rain forest tree Grevillea robusta. Journal of Applied Ecology, Oxford, 4(1):13-25; 22 refs.

Weeds of Australia, 2011. Fact Sheet for Grevillea robusta. http://keyserver.lucidcentral.org/weeds/data/03030800-0b07-490a-8d04-0605030c0f01/media/Html/Grevillea_robusta.htm

World Agroforestry Centre, 2002. Agroforestree Database. Nairobi, Kenya: ICRAF. http://www.worldagroforestrycentre.org/Sites/TreeDBS/AFT/AFT.htm.

Wu TL, 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised):384 pp. http://www.hkflora.com/v2/flora/plant_check_list.php

Ziller SR, Rosa F, 2001. Solicitaç¦o de colaboraç¦o para o workshop de 17-19 October 2001.

Contributors

13/04/15 Updated by:

Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Washington DC, USA

Distribution Maps

• = Present, no further details
• = Evidence of pathogen
• = Widespread
• = Last reported
• = Localised
• = Presence unconfirmed
• = Confined and subject to quarantine
• = See regional map for distribution within the country
• = Occasional or few reports

Download KML file Download CSV file

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Please click OK to ACCEPT or Cancel to REJECT

OK Cancel

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Please click OK to ACCEPT or Cancel to REJECT

OK Cancel