Rhamnoides hippophae Moench

Hippophaë rhamnoides is an arborescent armed, deciduous shrub or tree sometimes reaching up to 18 m. Crown irregular in shape with spiny, grey branches. Leaves linear-lanceolate, alternate, 2-6 cm long, covered on both sides with silvery-white scales, undersides with brown dots. Flowers inconspicuous, yellow,unisexual appearing before leaves. Fruit a 1-seeded drupe, reddish orange, varying in length from 5-12 mm. The ancient Greeks named the genus Hippophaë or "glittering horse," its leaves were part of the diet for racing horses, and they also believed that horses became plump and healthy when maintained on pastures with these trees. According to another legend, sea buckthorn leaves were one of the preferred foods of the Pegasus (flying horse). The species is distributed in more than 20 countries of Europe and Asia, and its morphological traits vary considerably according to this wide range of climatic conditions.

H. rhamnoides is dioecious and wind pollinated. Shrubs usually begin to bear fruit after three years and give maximum yields after seven to eight years. Male trees flower slightly earlier than females and for a period of 6-12 days. H. rhamnoides requires about 12-15 weeks from flowering until fruit become fully mature. Ripening can be as early as late July until early October in China, depending on subspecies, location and altitude. Leaves begin to fall at the end of October, when the average daily temperature falls below zero.

Prefers sandy soils with pH 9.5.

Sea buckthorn is native to the temperate zones of Asia and Europe, where it is widely distributed. It is also well represented at higher altitudes in the sub-tropical zones of Asia. China has the largest area (920 000 ha) under Hippophaë of any country, and also the largest variety of Hippophaë species. Sea buckthorn grows on sand dunes near the sea to the Eurasian plateau at 5 200 m. However, they are extremely drought tolerant, with extensive root systems that scavenge soil humidity and groundwater aggressively.

The species has a history of utilization that goes back at least 12 centuries. The ancient Greeks maintained pasture fields with these trees. The plant was widely used as a folk medicine in ancient Greece, the Roman Empire, Mongolia and Russia. The Tibetan medical classic, the RGyud Bzi or Four Books of Pharmacopeia, attributed to the Tang Dynasty (618-907 AD), lists 84 prescriptions for the preparation of sea buckthorn medicines. References to its medicinal use in Greece are found in writings of Theophrastus and Dioscorides. Russian immigrants took sea buckthorn to America at the beginning of the 20th century.

The species propagates well asexually because lignified branches of any age possess a strong ability to form adventitious roots. H. rhamnoides can also be propagated from softwood cuttings under mist. For introduction or breeding trials, seed propagation is the most suitable treatment. Seeds can be sown in autumn or stratified.

Management varies according to objectives and environment factors. Sea buckthorn is a light-demanding species, trees growing in forested areas die if the canopy density exceeds 50%. However, its wide adaptability and varied reproductive strategies indicate it could be a serious weed in some environments. Its extensive, suckering root system may make it unsuitable for agroforestry technologies that include close tree/crop associations. Removal of six year old sea buckthorn plantations can produce 6.32 t/ha of wood. To ensure adequate pollination, orchards should have between 7-12% of the trees as pollinators. In China six year old sea buckthorn plantations can produce 6.32 t/ha of wood. Thorny stems and branches often make it difficult to harvest the fruits. Estimates of 1500 hours/hectare for fruit harvesting can be expected. Mechanical harvesters have been tried with little success, removing branches from the tree works well, but is still very labour intensive. Expected yields are around 5-7 kg per plant or 4-5 t/ha. Plants should be spaced between 1-4 m. An annual growth of 10-20 cm is estimated for this species.

Holotrichia oblita, Gryllotalpa unispina and Agrotis segetum are the main underground pests in nurseries, attacking young roots. These can be controlled with poisonous baits and lamplight luring. Holcocerus arenicolus is another root-boring cossid. Defoliating pests include Malacosoma neustria testacea and Maladera orientalis. Fruit-eating pests include Rhagoletis batava and Curculio spp. Flooding in combination with pesticide applications can be used to control Gelechia hippophaes (sea buckthorn moth. Fusarium and Pythium diseases can be important diseases at the seedling stage.

With indoor storage seeds retain viability for 3-4 years. Under suitable conditions, they will germinate during any season of the year. In China plantation establishment has been successful by broadcasting seed from aircraft.

Erosion control: A good soil protector, useful for soil conservation, conserving water, and stabilizing sand dunes. Shade or shelter: H. rhamnoides is a shade provider. Reclamation: Sea buckthorn shows a strong tolerance for toxic pollutants in the soil and air. It can thus be used to revegetate heavily industrialized areas or to reclaim mining sites. With its hardy drought resisting attributes, this species is ideal for afforestating marginal areas. Nitrogen fixing: Hippophaë possesses a strong capacity to fix atmospheric nitrogen in its root nodules when associated with the actinomycete, Frankia. Most soils possess enough Frankia to support nodulation. In one stand on the east coast of England, annual nitrogen fixation was estimated as high as 179 kg/ha-¹. All of the plant's characteristics, especially its strong nitrogen-fixing ability and rapid growth, make it a good species for improving soil fertility. In mixed plantings, it can promote the growth and development of adjacent plants. Ornamental: Sea buckthorn is also useful as an ornamental shrub. Boundary or barrier or support: It is used successfully as a windbreak and to stabilize sand dunes, and several of its products have high value. Other products: Cosmetics derived from sea buckthorn are widely used in creams. Medicinal value of sea buckthorn oil is linked with its apparent ability to promote skin cell and mucous membrane regeneration, explaining its long use as a skin remedy and cosmetic aid with nourishing, revitalizing and restorative action. Day creams and a shampoo developed in Romania have received international patents.

Food: The fruit is edible and has a tart, bittersweet taste. Sea buckthorn fruit is rich in vitamins C, E, K, B1 and B2, as well as niacinamide, pantothenic acid, carotenoids and other substances such as oil, sugar, malic acid, amino acids and pectin. The vitamin C content of the Chinese sea buckthorn subsp. sinensis fruit can be as high as 1253 mg/100 g-1. In China, peasants have become prosperous by collecting and processing the fruit. Hippophaë leaves also contain various nutritious substances and minerals. A nutritious herbal tea, (shaji tea) high in vitamin C and trace elements is made from hand picked, young and tender leaves of H. rhamnoides. Fodder: Herdsmen in northwest China often feed sea buckthorn leaves to their animals. In Russia, fodder supplements of sea buckthorn by-products are reported to improve liveweights and coat condition. Feeding poultry with meal made from sea buckthorn fruit and fruit oil has been observed to increase the pigmentation of egg yolks and body fat. The oil also increases flesh pigmentation in rainbow trout. Fuel: The tree yields good quality fuelwood. Lipids: A valuable natural oil, sea buckthorn oil (shaji oil) rich in vitamin C, E, carotene (vitamin A) and essential fatty acids is obtained from the seeds. Alcohol: Sea buckthorn wine is well known in Russia where a new variety has been bred by hybridizing geographically distant plants. Medicine: The plant is considered a general panacea and extensive use is made of its roots, stems, leaves, flowers, fruits and seed. Oil from the fruit acts as an antioxidant and may thus be used to treat wounds, frost bite and pathological problems of the alimentary mucous membranes. Serotonin (5-hydroxy-tryptamine) extracted from sea buckthorn possesses antitumor capabilities.