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Gotska Sandön is dominated by pine forests, which in many places have become or are in the process of reverting to natural forests. In many places the forest is of the same vintage and height, but dead wood in the form of standing trees, high stumps and fallen trunks occurs relatively often. Due to the limited supply of water and nutrients and a thick ground cover the forests grow slowly. At ground level the vegetation consists mostly of heather, crowberries, cowberries (lingon), cup lichens, Schreber’s feather moss, broom moss and mountain fern moss. Even twin-flower, ericaceous plants, creeping lady’s tresses, and lesser twayblade can also be found. PINE FORESTS On parts of the island the pine forest has grown very dense. Here and there you can find former solitary trees, both living and dead, shaded nowadays by younger forest growth. Large parts of the forest are rather sparsely treed however due to the lack of nutrients and water, the often compact ground vegetation and that there are still areas where moving sand makes re-growth difficult.
Dendrochronical investigations show that forest fires have occurred 30 times since 1487. The majority of the fires were in the 16th and 17th centuries and were probably started by people wanting to improve the heaths for sheep grazing. The latest fire took place in 1880 when large parts of eastern Sandön were burnt down and then in 1917 when a smaller area of the south-eastern part burned. Even today you can find charred standing dead trees and trees with fire scars (welts on the trunks that are produced when the tree “repairs” a damage) witnessing to forest fires. The fires are not believed to have led to any extensive sand erosion, since the ground is seldom totally exposed during a forest fire and the remaining dead trees and fallen branches help to bind the sand. Re-growth of the forest and an increase in the amount of dead wood, which benefit mostly the wood insect fauna, are the most important effects of the forest fires on Gotska Sandön. Perhaps the repeated fires are also the reason why spruce trees are so rare on the island.
There are also traces of logging operations in the forest. In the 1820s an intensive logging period began and continued with a few minor interruptions right up until the 1940s. Much of the timber was meant to be used to build boats, which meant that the heaviest, highest and straightest of the pines were cut down. In the 1920s parts of the forest were “cleaned up” in the spirit of the times by thinning out the damaged and dead trees. Since the 1940’s though, only occasional logging has occurred, the latest in 1966.
DECIDUOUS FOREST Decoiduous forests or groves of leafy trees are found only in some 20 smaller areas on Sandön. The largest of them is Stora Idemoren (mor is the word for leafy trees in the local dialect on Fårö) south of the lighthouse settlement. In general the deciduous areas are found where there are dips in the ground bringing the ground water closer to the surface. The combination of plant species varies. At the tree and bush level, aspen, hazel, oak, pine, Swedish whitebeam, yew, Goat willow, mountain ash, birch and juniper are all represented. The ground vegetation here generally has a much richer number of plant species than that in the pine forest, and even here the combination of species varies from place to place. Some examples of species found are: liver leaf (hepatica), woodruff, wood millet, small cow-wheat, bracken, May lily, bearberry, common dog-violet, sanicle, fingered sedge, wavy hair-grass, stone bramble, twinflower and Danzig vetch. Among the orchids are found: narrow-leaved helleborine, red helleborine, lesser butterfly-orchid, bird's-nest orchid, common twayblade, and military orchids. The two helleborines sometimes create a hybrid with pink flowers, called Hybrid Helleborine.
SHORES Nearer the shore on the western and north-eastern sides of the island, lies the rubble-covered headland. Generally it lies between the ridge dune on the land side which is often covered with pines, and the gray fore-dune that consists of leached sand with a low nutritive content. The headland has relatively few plant species. Biatora lichens grow on the rubble, orange elegant sunburst lichens on the limestone and on the sandy parts mostly lichens, mosses and grey hair grass. Bearberries, biting stonecrop, windflowers and Breckland thyme also occur, as well as mountain everlasting on the headland inside Norra Sidan (the Northern Side).
The grey sand dune is seldom if ever affected by the waves from the sea and is leached of nutritive substances. It is often partially or completely covered by vegetation; common species are grey hair grass, sand sedge, reindeer lichen, and mosses accompanied by occasional clumps of marram grass. In certain hollows in the grey dune the ground is damper. Here the nutritive levels increase thanks to plant materials supplied by the sides of the dune and the shallow ground water level which results in a higher level of calcium. This means that the herbal vegetation becomes richer with bird’s eye primroses, common spotted orchids, dark-red helleborine, and marsh helleborine. The largest wet dune-slack has been Yttre dynkärret (the Outer Dune Marsh) which is nearly completely covered in sand nowadays. Thousands of Bird’s eye primroses bloom in Inre dynkärret (the Inner Dune Marsh) in the southern part of Bredsand in the springtime.
SAND DUNES Outside of the grey sand dune lies the white sand dune, which largely consists of exposed moving sand. Here nutritive levels are higher than they are in the leached grey dunes, especially closest to the sea where seaweed sometimes drifts in and fertilises the ground. Vegetation is dominated by marram grass which binds the sand. When the marram grass is covered by sand its growth is stimulated, the marram grows higher, and the wind deposits more sand which is bound by the marram which grows even higher, and so on. In some places the marram grass and the wind build the sand up to five-meter high dunes sharply sloping towards the sea with a flatter lee-side.
SHORE MEADOWS Along parts of the coast, areas which were nearly completely open ground earlier are gradually becoming overgrown. This is perhaps most evident on the “burg” or open flat areas at Bredsands udde (point), where sparsely-growing pine forests have spread closer and closer to the beach over the past 20 years and nowadays cover countless hectares that were previously open ground. Sand erosion kept the trees from getting established earlier. The pines have even begun to spread onto the grey and white dunes.
THE WOODLAND MEADOWS Several smaller meadows still exist on Sandön. The Chapel meadow south of the lighthouse settlement was overgrown for number of decades, but has been cleared of brush and is now mowed and maintained by the Gotska Sandön Hieritage Society. Here oaks, hazels, and the odd yew grow quite widely scattered while at ground level there are wood anemones, liver leaf (Hepitica), lady's bedstraw, common cow-wheat, Germander speedwell, buttercups, windflowers, sweet Vernal-grass, spring vetch, perforate St John's-wort, sheep's-fescue, hoary cinquefoil, mouse-ear-hawkweed, and harebells. The largest yew tree on the island with a circumference of about 155 cm grows in the Chapel meadow, east of the cemented dam. The oaks in the area have lung lichens growing on them, a species which ordinarily is found on ash and elms. ARABLE LAND The open land at Gamla gården (the Old Farm), which is also mowed, was formerly tilled fields and pastures, which is evident in the present flora. Among the plants that grow here are: yarrow, Germander speedwell, hare's-foot clover, Nottingham catchfly, common sorrel, windflower, common rock-rose, field bindweed, tormentil, forget-me-not, and greater knapweed. In the surrounding forest traces of earlier grazing can still be seen, for instance, in the aged junipers, remains of ditches and a relatively large number of deciduous trees and herbaceous plants.
DRY MEADOWS The dry meadows at Hamnudden display a rich flora, for instance, meadow saxifrage, windflower, heath dog-violet, Teesdale violet, common stork's-bill, common Whitlow grass, wild strawberry, Thale cress, common rock-rose, mouse-ear-hawkweed, bulbous buttercup, sickle medick, common restharrow, narrow-leaved everlasting-pea, salad Burnet, field wormwood, angular Solomon's-seal, Breckland thyme, spiked speedwell, moonwort, basil thyme, black medick, and the rare luddvedel (Oxytropis pilosa). Another rarity which also grows here is thyme broomrape, making Gotska Sandön probably its northernmost growing place in the world. Thyme broomrape is lacking in chlorophyll and lives as a parasite on the roots of Breckland thyme.
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