Grevillea robusta (silky oak).

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). It provides economically valuable products including timber, poles, firewood and leaf mulch; it is easy to propagate and establish and is relatively free of pests and diseases; its proteoid roots help it grow in low-fertility soils; it does not compete strongly with adjacent crops; and it tolerates heavy pruning of its roots and branches. With its fern-like pinnate leaves and prominent attractive, orange flowers, it is also popular as an ornamental. As a consequence of its colonizing abilities, G. robusta may become a noxious weed in favourable conditions.

Can Brisbane Remain a Subtropical City?

As the seasons change, public and private gardens become a riot of colour. Winter shows the scarlet flags of poinsettia – Brisbane's emblem, which, if really a Mexican beauty, has made itself very much at home. The lavender glow of jacaranda and the gold of laburnum, the green umbrella of poinciana crowned with gleaming scarlet, the massed magnificence of magenta bougainvillea, the creamy blossoms and heavy tropical scent of frangipani filling the air with sweetness, the glare of cannas, the pink and white of bauhinia, the old-gold feathers of silky oak and the red and green of hibiscus – these are but a few of the array of colours.C. C. D. BrammallBrisbane has been relentlessly cleared since the first British soldiers and convicts set up at Redcliffe and then moved to the site we know as Brisbane today. As in other Australian colonies the new settlers were keen to grow crops and to exploit the timber both as a building material and later as a rich source of export income. While early explorers and botanists recorded the richness of the vegetation most new settlers saw the landscape as a resource to be exploited, not a pristine environment to be treated with respect.

Apuntes sobre algunas latifoliadas de maderas valiosas. 4. Grevillea robusta A. Cunn

Grevillea robusta es un árbol nativo de Australia, descubierto y descrito por el explorador europeo Alan Cunningham en 1827. La especie pertenece a las angiospermas, dicotiledóneas, familia Proteaceae, y es llamada simplemente silky oak, grevillea géant, roble sedoso, silver oak, he-oak, o simplemente grevillea, y su sinónimo es Grevillea umbricata A. Cunn. Esta especie australiana es la más grande de su género, que comprende más de 260 especies, alcanzando alturas de 40 m y diámetros de hasta 1,2 m. La especie ha despertado gran interés, pues se trata de un árbol de fácil adaptación, de rápido crecimiento y con objetivos múltiples. En su región de origen es la especie de mayor resistencia, regenera vigorosamente y coloniza en forma agresiva las áreas alteradas. Para ser un árbol tan grande crece rápidamente y tiene éxito en un amplio rango de condiciones climáticas y edáficas, lo que lo hace de un gran interés. El éxito que ha tenido la especie se debe entre otros factores a su variedad productiva, no quedando excluida de ningún producto o servicio. Principalmente en las áreas bajas y secas, los agricultores han encontrado que la grevillea se reproduce y maneja fácilmente, presenta buenos rendimientos de leña y postes y no compite notoriamente con los cultivos adyacentes.

Herbicides for Container-grown Rain Forest Species

Four granular formulations of preemergence herbicides-oxadiazon, oxadiazon in combination with simazine, dichlobenil, and oxyfluorfen + oryzalin-were evaluated for weed control and phytotoxic effects on 10 species of container-grown Australian rain forest plants. Herbicides were applied at half and at one and two times the manufacturer's recommended rate. Oxyfluorfen + oryzalin, oxadiazon, and oxadiazon + simazine controlled all weed species at half the recommended rates (1.0 + 0.5, 2.0, and 2.0 + 0.5 kg·ha-1, respectively) with no phytotoxic effects after 10 weeks to nine of the 10 rain forest species tested: broad-leafed lilly-pilly [Acmena hemilampra (F. Muell. ex Bailey) Merr. and Perry], red ash [Alphitonia excelsa (Cunn. ex Fenzl) Reisseck ex Benth.], rusty bean [Dysoxylum rufum (A. Rich.) Benth.], macaranga [Macaranga tanarius (L.) Muell. Arg.], fibrous satinash [Syzygium fibrosum (Bailey) T. Hartley and Perry], Queensland golden myrtle [Metrosideros queenslandica L.S. Smith], cluster fig [Ficus racemosa L.], corduroy tamarind [Arytera lautereriana (Bailey) Radlk.], and celerywood [Polyscias elegans (F. Muell and C. Moore) Harms]. Dichlobenil depressed plant growth of red ash and failed to control bittercress (Cardamine hirsuta L.) and green amaranth (Amaranthus viridus L.), even at twice the recommended rate (4.0 kg·ha-1). All herbicides applied at half the recommended rates produced minor to moderate plant injury within 5 weeks of the first application to corduroy tamarind and northern silky oak [Cardwellia sublimis F. Muell.]. A second application 10 weeks after the first caused no significant plant injury to corduroy tamarind but resulted in severe plant injury to northern silky oak. This finding validates the previously reported sensitivity of Proteaceous spp. to preemergence herbicides. Chemical names used: (2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4 oxadiazoline-5-one) (oxadiazon); (2-chloro-4,6-bisethylamino-1,3,5-triazine) (simazine); 2,6-dichlorobenzonitrile (dichlobenil); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); and 3,5-dinitro-N4,N4 -dipropylsulfanilamide (oryzalin).