Sea Buckthorn

Hippophae rhamnoides

The Sea Buckthorn is a deciduous, scaly and thorny shrub which is native to most parts of Eurasia. An unpretentious plant which holds up well against the elements, the Sea Buckthorn develops an extensive root system, even in poor soil, and is often a pioneer plant in dry river beds, on gravel banks, at high elevations, or on rocky cliffs. Its attractive, bright orange fruit contains high levels of vitamin C, which has made the Sea Buckthorn a popular crop in some parts of the world. In the National Park, this shrub may commonly be found in the xeric, or extremely dry, habitats of the Lobau.

Description
The Sea Buckthorn is a thorny shrub or small tree with widely-spreading branches, normally growing straight, not crooked, and reaching heights of 6m (at most 10). Above ground, the spiny shrub acts as a natural windbreak and barrier; below ground it develops an extensive, deep, creeping root system, while at ground level there is much suckering. Of great ecological significance is the species' interaction with a class of bacteria called Actinomycetes, which enables it to convert atmospheric nitrogen to a form that can be used for food; this symbiosis also serves to improve the quality of the soil. Fully-grown shrubs often have a rounded habit. Both the tree and shrub forms of the Sea Buckthorn sprout annual shoots whose tips lignify during the first growing season. The spreading twigs with short shoots which have turned to thorns are initially glandular-pubescent, dark reddish-brown to grey in colour. Later the bark becomes smooth and, as a mature plant, flaking. Winter buds are globate to egg-shaped and bud scales are a coppery gold and minutely haired. The alternating leaves with very short stalks are unbroken, have a lineal or lancet-type form with a length up to 6.5cm and width up to 1cm. Top of the leaf is greyish-green with a silver gloss; underside is dull silver white. Leaf margin is slightly rolled-up. As early as midsummer the leaves may turn a dark reddish-brown. The Sea Buckthorn flowers in early spring (March/April), long before foliation. A dioecious plant, its small (approx. 3mm in size), inconspicuous flowers are found at the base of the previous year's growth. After flowering, the female head, which is conical in shape, develops into a bladed shoot. The numerous berry-like stone fruits (achenes), which mature in August-September, develop out of the calyx. In the beginning they are bright orange, later almost white, with a diameter of approx. 8mm. They are sour to the taste. The berries remain on the shrub over the winter and are eaten by diverse bird species, but also by foxes and wild boars. Sea Buckthorn timber is fine-grained, moderately heavy and has a sheen. It has narrow yellow sapwood and lively brown heartwood which is sought after by turners.

Distribution
The Sea Buckthorn is a Eurasian floral element and is represented by four subspecies in Europe, Asia Minor and the Far East. Its range extends in a broad band from the Pyrenees to the foothills of the Alps, the Alps themselves; to the Caucasus; and all the way to the steppes and mountains of southern Siberia and Tibet. The species is particularly widespread along the gravel banks of Alpine rivers such as the Salzach, Inn, Isar, Lech and Danube, but it also occurs in sand dunes near the shores of the North and Baltic seas. Extreme montane specimens have been documented at high elevations of 4000m and even 5000m, for example in Tibet or in the Pamir mountain range. At the heart of Central Europe, where the species is not naturally occurring, the Sea Buckthorn has been able to naturalize itself after having been cultivated. In Austria, the species is non-occurring in Burgenland and Styria. In the Donau-Auen National Park, it is most often found in the xeric habitats of the Lobau.

Endangerment and Conservation Status
The Sea Buckthorn, which in our latitude thrives best on gravel banks, has been negatively impacted by intensive river regulation and construction activities along Alpine rivers. In many parts of Europe, the species is listed as lower risk but near threatened. In Austria, it is vulnerable in certain climatic regions, such as the Pannonian Plain and in the northern Alpine foothills. In the National Park, it is found mainly in the extremely dry habitats of the Lobau, where the species is in part stand building.

Ecological Characteristics
In light of the Sea Buckthorn's very expansive natural range, it is difficult to formulate location conditions which are generally prevailing. As a rule, it favours loose, aerated soils with access to ground water in sunny locations. The species is also documented as an indicator for low-nitrogen, calcareous soils or those not rich in humus. It is thus often a pioneer plant in dry river beds on sand and gravelly soils, on gravel beds at high Alpine elevations, on rocky cliffs, sparse areas within pine and dry forests, as well as on sand dunes in coastal areas. Its natural occurrence thus extends from flat lowlands to high mountains.

Special Characteristics
Two special attributes have made the Sea Buckthorn an ecologically and commercially viable shrub. First, its expansive root growth enables it to prevent soil erosion and wind erosion, for example on gravel beds and sand dunes. At the same time, soil is fortified thanks to its nitrogen-fixing capabilities resulting from the above-mentioned symbiosis with the Actinomycetes. Second, its tart-sour fruits contain substantial amounts of pure ascorbic acid and are thus a suitable and easily-accessible source of vitamin C. In fact, the fruit of the Sea Buckthorn contains five times as much vitamin C as most citrus fruits; it also contains glycosides, calcium, organic acids, oils, pro-vitamin A and the B1, B2, B6 and E vitamins, which work to stimulate circulation and metabolism, improve heart and kidney functions, and help prevent colds, scurvy and much more. To better exploit these properties, this vitamin-rich plant is cultivated on large plantations in Eastern Europe and Asia, in particular. Yet the oils in its pulp are equally important and are used to alleviate stomach and intestinal maladies, and to treat radiation burns. In Central Europe, the ripe fruit has traditionally been used to make juices, conserves, fruit salads and is also used in baking. The freshly-squeezed juice tastes vaguely "orangey" and is often obtained directly from the bough using squeezing instruments made of wood. Finally, the Sea Buckthorn is a valuable plant in naturopathy.