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912 Uppsatser om Tree species - Sida 21 av 61
Utvärdering av Naturvårdsverkets bedömningsgrunder för makrofyter i sjöar
According to the Water Framework Directive of the European Union, macrophytes should be used as indicators in the ecological and environmental monitoring of lakes. In the member state Sweden the Environmental Protection Agency has elaborated assessment criteria for determining lake status based on macrophytes. The main focus of this thesis is to evaluate the efficiency of the assessment criteria for macrophytes. In addition the concordance between the ecological status classes of the four quality factors included was analysed.The assessment criteria for macrophytes are based on the total phosphorus preference of the respective species. The focus is thus mainly on the nutrient level of the investigated lakes and the environmental problem monitored is eutrophication.
Naturvårdande skötsel (NS) - blir resultatet som man tänkt sig? : en fältstudie över föryngring, trädslagsfördelning och död ved 14 år efter åtgärd
A new Swedish political approach to forestry was initiated 1993, that put goals of production and environmental issues into equal importance to Swedish Forestry Law. Earlier nature conservation very often declaimed preservation the best way to conserve nature, but recently it is clear that many highly biological values are due to former land use or disturbance. Many old pastures or cultivations dominated by deciduous trees are today characterized by a dense overgrowth of Norway spruce. By actively paying attention to nature in forestry (nature restoration), it is possible to partly reconstruct habitats or disturbances that are necessary to favour the biological values.
The aim with this master thesis is to study the nature restoration, (NS, Swedish abbreviation), performed in 11 forest sites in the middle of Sweden 8-14 years ago. Since NS recently have become applied, it has never yet been evaluated.
Serum Amyloid A as a possible marker of health and disease in non-domesticated mammals : a retrospective pilot study of SAA levels in dolphins, elephants and tapirs at Kolmården Wildlife Park
The veterinary handling of wildlife, both in zoos and in the wild, commonly requires that the patients need to be captured and immobilized for examination or treatment. This emphasises the need for quick, on-site, laboratory equipment, in order to minimize the analysis time and thus the stress for the animal and also in order to increase the possibility of starting relevant treatment early on.
The aim of this pilot study was to determine whether Serum Amyloid A (SAA) could be a measured in blood samples from bottlenose dolphins (Tursiops truncatus), Asian elephants (Elephas maximus) and South American tapirs (Tapirus terrestris). SAA rises to its maximum about 24 hours after the introduction of an inflammatory agent in companion animals. This also correlates with the estimated time it takes for animals at Kolmården Wildlife Park to be examined and having blood samples collected after being observed as sick. The study also evaluated whether the Eurolyser SOLO, using a turbidometric immunoassay (TIA) developed for human diagnostics, could be used for such analysis.
This pilot study was a retrospective analysis of SAA in convenience sampled frozen serum, collected from dolphins, elephants and tapirs.
Ekonomi vid uttag av långa toppar som skogsbränsle i slutavverkning :
The market for biofuels from the forests have had a positive development and the job initiators for this master´s thesis wanted to examine the profitability of a method for harvesting forest fuel, which was unfamiliar to them. The method was the ?long tree tops-method?, here called the LT-method.
The LT-method is characterised by the fact that timber is harvested as the only roundwood assortment while the rest of the stem, which in other cases would become pulpwood, is harvested as forest fuel together with the logging residues. The method is based on the assumption that advantages in handling of the forest fuel assortment such as increased load weights for forest hauling and truck transportation, should compensate for the lower price for pulpwood when sold as forest fuel.
The aim of the study was to compare the profitability of the LT-method with the GROT-method (harvest of timber, pulpwood and logging residues) and conventional logging without any harvest of forest fuel, and aslo to try to identify factors affecting the profitability of the different methods.
Goat production in Laos and the potential of using Erythrina variegata as a feedstuff
Lao People?s Democratic Republic (PDR) is a country where the majority of the population works within the sector agriculture in one way or another. The number of goats are increasing and the animals can be an important income source for families. However, during the dry season, lack of feed is a great problem for the farmers. Fodder trees have shown great potential as dry season feeding, due to that the trees often hold green and fresh leaves a long time into the season, compared to grass that dry out quickly.
Inventering av vecklare i Svenska äppelodlingar
Over the last couple of years, growers, researchers, advisors and plant protection companies have noticed increasing problems with tortricids in Swedish apple orchards. Since the insecticide Gusathion (azinphosmethyl) has been banned (end of 2008; KemI 2008), a further increase of tortricid populations can be expected. In order to get a picture of species composition and population densities among the tortricids, an inventory of seven species, Adoxophyes orana, Archips podana, Archips rosana, Cydia pomonella, Hedya nubiferana, Pandemis heparana and Spilonota ocellana was made in 11 orchards in southern Sweden (Skåne) in 2008. Population densities were estimated by bud sampling (April 20-25), pheromone trapping (May 5-September 22) and assessment of fruit damage (September 9-12). In all orchards A.
Lek hos Stinkpadda (Bufo callamita): jämförelse av restaurerade och ickerestaurerade hällkar
The natterjack toad (Bufo calamita) is one of three species of toads living in Sweden. During the last decades declines in population numbers have been detected and are thought to be primarily due to loss of habitat, overgrown breeding ponds and competition from common toad (Bufo bufo) and common frog (Rana temporaria). In 2012 20 ponds in the location of Glommeskallen in Smögen were restored by clearing the ponds from overgrowth. The aim of this study was to investigate if natterjack toads used the restored ponds and if the restoration had made an impact on the natterjack population on the location. Presence of common toad and common frog was recorded, as was the presence of eggs and larvae of any of the three species.
Elementkoncentrationer i gran utmed en markfuktighetsgradient :
One key factor in silviculture today is sustainability. In order to achieve sustainability it may be important to restore lost nutrients to the forest after clearcutting. In order to calculate the removal, you need to know how much of different elements you will find in different tree compartments. The aim of this study was to investigate if the concentration of elements in different tree compartments of spruce (Picea abies (L.) Karst) were related to the moisture conditions of the site. Five plots at Risfallet (60º 21´ N, 16º 13´ E), was placed along a moisture gradient in a 40- year spruce stand.
Bräkanden från förr : att skilja får från getter utifrån kv. Apoteket 4-5 i Visby
To differentiate between bones from sheep (Ovis aries) and bones from of goats (Capra hircus) is a long lasting challenge for zoologists, archaeozoologists and osteologists. Especially considering archaeological remains which are often found fractured and poorly preserved due to taphonomic processes. Zeder & Pilaar?s (2010) and Zeder & Lapham?s (2010) methods of species differentiation has shown promising results when used on bones from modern sheeps and goats. This paper aims to evaluate these methods by exerting them on excavated bones from kv.
Askgödsling och dess lämplighet i torvmarksskogar tillhörande Sveaskog Förvaltnings AB : en litteraturstudie
During whole-tree harvesting, there is a risk that the soil will become impoverished of nutrients. To prevent this, nutrients are returned to the harvested site as wood ash. This action also reduces the risk of soil acidification. Nevertheless, the ash does not result in any increase of tree growth if it is added on mineral soils, which is where the measure is most commonly used in Sweden. Due to the lack of growth response, the interest from landowners is small, which is why ash amendment today is not done enough to compensate for the need.
Platt Hierarki : Metoder för omvandling av relationsdata till hierarkisk data
The relational database model was defined in the 1970?s and is the dominating database type today. The main difference between data from a relational database and a hierarchical data structure is that the relational database stores records in tables. The records have no particular order, but can include links in terms of relationships with other records. A hierarchical structure organizes data in the form of a tree structure and can for an example be found in organizational structures in which different levels involves different responsibilities. If the data stored in a relational database is to be presented in a hierarchically, a conversion of the data structure is required. The intention of this paper is to describe how such a conversion can be performed. To investigate the conversion methods, case studies has been conducted on the basis of a specific organization?s hierarchical structure.
Lilaköttig taggsvamp, Sárcodon fuligíneovioláceus : miljökrav i Sverige och en analys av vad som styr artens etablering
Burnt Spine-cap Sárcodon fuligíneovioláceus are one the most endangered
mycorrhizal fungal species in Europe. They have their main distribution in Sweden. It
form mycorrhiza with pine and dependent on limestone, which makes it connected to
a rare environment. It has therefore been important to study the ecology of it further
and to recognise the requirement it has on the environment more accurate and what it
need to establish in a new area. In this study, 31 of 34 known sites in Sweden was
visited and studied in field and their history analysed through aerial photographs.
Tidsstudie av containerhuggbil
The fork lifter chipper truck is a concept which has been developed for harvest and transport of bio fuel. The system consists of one fork lifter chipper truck and 1, 2 or 3 transport lorries, usually two, which serves the fork lifter chipper truck. The system is driven by the fork lifter chipper truck that produces chipped material into a container on the truck. When the container has been filled the truck drives to the landing site where it?s offloaded.
Effects of ten year old enrichment plantings in a secondary dipterocarp rainforest : a case study of stem and species distribution in Sabah, Malaysia
Large areas of forests in the tropical region have during the last decades been lost and converted to new land uses while other areas have been degraded into secondary forests. These secondary forests need to be restored and rehabilitation through enrichment planting and liberation may help to speed up the recovery process. The objective of this thesis was to evaluate a rehabilitation method that includes enrichment planting, slashing of weeds and girdling of unwanted trees. The site for the project is situated in Sabah, Borneo in a secondary forest which had been logged and burnt by a wildfire. The project?s goal is to rehabilitate and increase biodiversity through enrichment planting of seedlings mainly belonging to the family Dipterocarpeaceae (dipterocarps).
Förutsättningar för återintroduktion av stora gräsätare i Sverige
Biodiversity is under threat in Sweden and many species are on the brink of extinction. This is mainly due to the large-scale drainage projects during the 19th and 20th century and the increasingly intensive land use in agriculture and forestry. The intensive land use with sharply defined boundaries between the production units has in many cases led to either overgrazing or overgrowing. As a result many species have been pushed back to "leftover" habitats like shooting ranges, power line corridors, roadsides, dumps, embankments and other similar areas. Therefore the question has been raised, wether or not it is needed to re-introduce large herbivores into the wild in order to maintain the biodiversity that is related to the extensive land use.This study has been conducted as a literature review and will focus on the European bison?s (Bison bonasus) impact on other species and biodiversity; conditions for reintroducing large herbivores in Sweden are also discussed.Free roaming populations of large herbivores have a positive impact on plants, insects and many other groups of organisms.