Suchergebnisse

During the 19th-century many lakes in Sweden were lowered because the need of agriculture land was high. The population was increasing so the government decided to lend money to farmers that wanted to expand their land. Today we are experiencing the environmental results of these actions. Hydrological effects like changed flowing directions and the damping effects of the lakes have been taken away. The management of the forest is also affecting the water system. In the catchment of Gråskaån several lakes has been lowered and a lot of land has been drained. The result is a quick outflow of water to the sea, when it's raining or when the snow is melting. Measurements in the field and also simulations with the HBV light model shows a quick decrease in flow when it's receiving water, during the summer months anyway. Computer simulations shows that during the 1980's the flow was higher, that is probably because of larger amount of precipitation during the 80's. The winters were also colder and that gives a larger amount of snow accumulation and more melting water in the spring. The low water flows are also affecting the fishes. The county administrative board of Stockholm wants to have a stock with salmon trout in Gråskaån. Therefore there have been projects going on, since the year of 1976, with putting out salmon trout in the river. In May 2003 were the last time for that, and test fishing in October the same year showed that there was no trout left in the river which is probably because of the low water flow during the summer months. The fish are responding to low water flows with heading downstream, and in this case, the fish probably swims out to Edeboviken. During the flow measurement the stream velocity varied between 37 cm/s and 1 cm/s. The salmon trout needs at least 15 cm/s to survive. So the big variation in water flow causes big problems. The salmon trout was reproducing in the stream during the 1980 but not anymore and that is probably because of the larger amount of precipitation during that time compared to now. So in order to keep the salmon trout in the river some counter measures has to be made. Countermeasures like damming of lakes to ensure a water flow during summer when the stream sometimes is completely dry, is one of the things that can be done. Also countermeasures like the removal of plants and construction of god playing grounds for the salmon trout has to be done in order to keep the fish in the stream.

The grandiose, but failed, attempts to produce silk in Sweden in the past have been largely ignored by historians. This thesis describes the history of sericulture in Sweden, including three periods of practical trials in 1735-1765, 1830-1898 and 1913-1918. For a long time, the secrets of sericulture were closely guarded in China but by the beginning of the 16th century, knowledge of silk cultivation techniques had reached a number of European countries. The pursuit of domestic silk production was often a costly undertaking instigated by royalty. Since conditions in Sweden and Denmark were partly similar, there was some degree of influence and cooperation between these neighbouring countries. The chapters dealing with attempts at silk production during the 18th century and the history of sericulture in northern Europe are primarily based on printed sources and literature. Several of the 18th century silk farmers documented their experiments, allowing us to follow their efforts and ideas on the feasibility of silk farming in Sweden. The descriptions of the two latter sets of Swedish silk production trials presented in the thesis are primarily based on archive materials, mainly consisting of minutes and annual reports. The history of sericulture in Sweden began in the mid-1730s, when Mårten Triewald conducted experiments and exhaustively described and published these. Carl Linnaeus was a significant influence in Swedish sericulture during this early period. Naturalists were hired as plantation managers and were tasked with supplying the silk industry in Sweden with home-produced raw material. The work was prompted by the desire to find an alternative for the huge Swedish imports of raw silk from China and Southern Europe. However, silk farming never became particularly common, despite the financial incentives available for producing silk and planting mulberry trees during the 1750s in the belief that some 'extravagance' was beneficial for society as a whole. When the 'Hats' position of power ended, so did the financial support for manufacturing luxury goods. Founded in 1830, the Swedish Association for Domestic Sericulture was active for nearly 70 years thanks to foreign influences and the notion that silk farming could be a popular livelihood. Members of the Swedish Royal Family served as patrons and several well-known scientists participated in the projects. The Association furnished mulberry plants and seeds, together with silkworm eggs, most of which were distributed to plantations controlled by the Association or county agricultural societies. However, the Association's annual reports show that many private individuals also planted mulberry trees and some pursued silk farming. Sericulture growing trials were carried out at a number of sites across Sweden, on the initiative of Jacob Berzelius, among others. These trials were mainly funded by Government grants, but numerous wealthy individuals also made contributions to the sericulture venture. Some income was generated by the silk products produced, which were almost solely bought by the Swedish Royal Family. The Swedish Sericulture Association was founded in southern Sweden in 1913 but this third brief foray into sericulture produced few results. All three periods of sericulture trials were initiated by enthusiasts with a firm belief that some silkworm host plants would survive the Nordic climate. There were a number of claims that the white mulberry tree had become acclimatised, but an equal number of cold winters and springs proved the opposite. Ultimately, Swedish sericulture was never economically feasible, since the natural conditions were unfavourable and the output from Swedish silk production was modest, and the cost high, in relation to imported silk. The almost 200-year history of sericulture in Sweden provides an important glimpse into the obsessions and culture of the age, but there were far too many obstacles for the dream of Swedish silk ever to become a reality.