Geography of Norway - Vegetation

Vegetation

Natural vegetation in Norway varies considerably, as can be expected in a country covering such a variation in latitude. There are generally fewer species of trees in Norway than in areas in western North America with a similar climate. This is because the migration routes after the ice age is more difficult in the north - south direction in Europe, with bodies of water (like the Baltic Sea and the North Sea) and mountains creating barriers, while in America there is a continuous continent and the mountains follow a north - south direction. However, recent research using DNA- studies of spruce and pine and lake core sediments have proven that Norwegian conifers survived the ice age in ice - free refugees even north to Andøya. Many imported plants have been able to ripen seeds and spread, and less than half of the 2,630 plant species in Norway today actually occur naturally in the country. About 210 species of plants growing in Norway are listed as endangered, and 13 species are endemic. The national parks in Norway are mostly located in mountain areas; about 2% of the productive forests in the country are protected.

Some plants are classified as western due to their need for high humidity and/or low tolerance of winter frost; these will stay close to the southwestern coast, with the northern limit near Ålesund; some examples are holly and bell heather. Some western species occur north to Helgeland (such as Erica tetralix), some even to Lofoten (such as Luzula sylvatica). The mild temperatures along the coast allows for some surprises; some hardy species of palm grow even as far north as Sunnmøre, one of the largest remaining Linden forest in Europe grows at Flostranda in Stryn and planted deciduous trees such as horse chestnut and beech thrives north of the Arctic circle (as in Steigen).

Plants classified as eastern need comparatively more summer sunshine, with less humidity, but can tolerate cold winters; these will often occur in the southeast and inland areas, examples are Daphne mezereum, Fragaria viridis and spiked speedwell. Some eastern species common in Siberia grows in the river valleys of eastern Finnmark. There are also species which seems to be in-between these extremes, like the southern plants, where both winter and summer climate is important (such as pedunculate oak, European ash and dog's mercury); other plants are dependent on the type of bedrock.

There are a considerable number of alpine species in the mountains in Norway; these will not tolerate summers that are comparatively long and warm or can not compete with plants adapted to a longer and warmer growing season; many alpine plants are common in the North Boreal zone and some in the Middle Boreal zone, but their main area of distribution is on the alpine tundra in the Scandinavian mountains and on the Arctic tundra. Many of the most hardy species have adapted by using more than one summer to ripen seeds. Examples of alpine species are glacier buttercup, Draba lactea and Salix herbacea. A well-known anomaly is the 30 American alpine species, which in Europe only grow in two mountainous parts of Norway; the Dovre-Trollheimen and Jotunheim mountains in the south and the Saltdal to western Finnmark in the north (Gjærevoll, 1992, pp 146–160; Moen, 1998, p 52). Other than in Norway, these species grow only in Canada and Greenland, such as the Braya linearis and Carex scirpoidea. It is unknown whether these survived the ice age on some mountain peak penetrating the ice, or they spread from further south in Europe, or why did they not spread to other mountainous regions of Europe. Some alpine species have a wider distribution and also grow in Siberia, such as the Rhododendron lapponicum (Lapland rosebay). Other alpine species are common in the whole Arctic, some only grows in Europe, such as globe-flower.

The following vegetation zones in Norway are all based on botanical criteria (Moen, 1998; Gjærevoll 1992), although, as mentioned, some plants will have specific demands. Forests, bogs and wetlands, as well as heaths, are all included in the different vegetation zones; a South Boreal bog will differ from a North Boreal bog, although some plant species might occur on both.