Quadria heterophylla Ruiz & Pav.

Gevuina avellana is a medium-sized evergreen tree, 10-12 m, rarely over 15 m high; canopy compact but much more open under shady conditions; branches stout, pubescent; young shoots covered in dense reddish hair. Leaves large, bipinnate, leaflets glossy, coriaceous dark green with serrated margins. Inflorescence racemose, flowers snow- to ivory-white, borne on the outside of the canopy in pairs; tepals 4, fused into a single structure with stamens curving back at anthesis to reveal the simple style and ovary. Fruit a globose, woody drupe derived from an indehiscent follicle; 1.2-2.3 cm diameter, coral-red when mature then brown or black. Seed 1, globular with smooth, tough shell. Gevuina is a monospecific genus restricted to the southern Sub Antarctic forests of South America. The specific epithet means hazel or nut-brown.

The tree is hermaphrodite but seems to require or benefit from out-crossing. Flowering starts from February-May in the late Chilean summer and early autumn, attracting a variety of insect pollinators including honeybees. Fruits ripen at the following year’s flowering time. Trees take up to 7 years before fruiting.

G. avellana prefers highly organic and well drained volcanic soils, although it will also grow well on almost swampy and shallow, eroded, acidic soils.

G. avellana is an understorey tree common in the Valdivian forests of southern Chile. These diverse subantarctic forests show many Gondwana affinities. It grows from the snowline of the Pacific slopes of the Andes to the coast in areas that have Mediterranean (mild moist temperate maritime) climate with occasional radiation freezes in spring and autumn, as well as winter frosts. The habitats are open areas where forest vegetation regenerates spontaneously and Proteaceae are important in the secondary communities.

The tree has been introduced to England, Ireland and California in areas with mild, moist climates. Efforts to develop gevuina nut commercially have been made in New Zealand since the 1950s.

Gevuina is easily propagated from seed or cuttings. Sowing should be in early autumn, without pretreatment, in normal substrate. Survival can be enhanced by germination under sterile conditions or treatment of cuttings with 80 % fosetyl-aluminium at 5 g/l at 28 days intervals. In an experiment using in vitro techniques, germination started 7 days after sowing and was complete in 32 days, with 92% germination. The tree roots easily but is difficult to establish due to the weak root system making it extremely sensitive to transplanting outside its native habitat.

The tree requires protection from strong winds due to the weight of foliage. G. avellana shows a 2-year rhythm in seed production which is concentrated in summer and autumn. Spacing of 2-4 m x 2-4 m has been used in trials in Chile. The tree does better on sunny slopes, it coppices well.

A fungus, Pestalotia truncata [Pestalotiopsis theae] has been isolated from the leaves of G. avellana. One of the main limitations to gevuina propagation is infection with Phytophthora cinnamomi. Mature trees have been known to wilt and die abruptly. Broad mites (Polyphagotarsonemus latus) pest on seedlings and the leaf roller caterpillars (Tortricidae) damage young leaves.

Erosion control: The tree is found on badly eroded slopes and has potential for erosion control by binding soil liable to erosion. Reclamation: It is a pioneer species tolerating situations occasioned by sun, wind and frost; qualities which can be exploited for reclaiming sites where top soil has been destroyed. Ornamental: Gevuina is an attractive garden and park specimen with showy sprays of creamy flowers contrasting vividly with the dark green foliage and bright red nuts.

Food: The fruit pulp and kernel are edible. The kernel is similar to hazelnut (Corylus avellana) in appearance and flavour and is eaten fresh or roasted. The protein concentration after oil extraction has been found to be 16 %. Of the 18 amino acids found in the flour, glutamic acid, followed by aspartic acid and arginine, are present in the greatest concentrations; lysine is the only limiting essential amino acid when compared with the FAO/WHO standards. Coupled with its low fat and high fibre content, gevuina flour has prospects as a health food. The whole nut is processed into a gevuina butter paste of high nutritional value, which can be at par with peanut butter. Fodder: The high protein content of cracking residue is used as stock feed. Apiculture: Flowers have abundant nectar and are excellent bee fodder. Timber: The timber is pale brown with an attractive grain, light, strong, durable and easy to work. It is used in its native range for turnery, musical instruments, picture frames, furniture and shingles. Tannin or dyestuff: Husks left over after nuts processing are rich in tannin. Lipids: Lipid content is comparable to rapeseed, sunflower and peanuts. The oil is of high quality as table oil rich in polyunsaturated fatty acids such as linolenic and ecosaenoic. G. avellana nuts are rich in oils that have health-cosmetic purposes. The oil is particularly high in palmitoleic acid (up to 27.6 %), which is a good natural UV filter for sun lotions. Other products: Its fine foliage is in demand in the cut flower market.