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1245 Uppsatser om Mixed boreal forest - Sida 38 av 83
Frigörelse av fosfor från färskt, fryst och torkat växtmaterial : ett laboratorieförsök för att öka förståelsen för fosfordynamiken inom växtodlingen
Phosphorus is the single most potent contributor to eutrophication of freshwater and has also been shown to contribute to the toxic algae blooms in the Baltic sea. The
dynamics and paths of losses of phosphorus from arable lands are not fully understood.
It is known that phosphorus can be lost directly from plant material to water.
In studies where plant material has been subjected to several freeze-thaw cycles, large amounts of phosphorus have been lost. Most studies have been conducted
under field conditions, with many factors effecting the measured losses of phosphorus, such as weather and type of soil. This study was performed in a controlled environment without the presence of soil. Instead of soil, small glass beads were mixed with the plant materials in vessels, to make possible homogeneous leaching with water through the mixture of glass beads and plant materials.
In this study, clover, ryegrass and dry straw were cut to pieces, approximately 2 cm long.
En studie av sedimenttransport, död ved och kantzoner längs två vattendrag i Kilsbergen - från skog till slätt :
Headwater streams are affected by anthropogenic impacts at multiple scales.
One aspect of human impact is sediment transport associated to the
abundance of stream structures as large woody debris and the composition
of the riparian zone from forest to agricultural landscapes.
Riparian buffer zones and stream structures like dead wood are considered
as generally important structures for protection against an increasing
amount of sediment particles in the water. Hence, in this study these
structures were quantified in thirty different stream segments on land and in
the water.
To measure the transport of sediment Whitlock-Vibert boxes were used in
three different types of landscapes; forest, transition and fields. The boxes
were left in the stream segments for three months, the taken up and dried
and weighed. The results showed that the transition-land in Frösvidalsån
had the highest sediment transport. The second highest transport of
sediment was in Blackstaån at the fields.
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.
Ersättningsmodeller för ballasttransporter : vid anläggning och underhåll av skogsbilvägar
Construction and maintenance of forest truck roads are a necessary element of industrial forestry. Payment for contracting services in this context can be done according to a number of payment models. This study will focus on the methods and consequences associated with a change of Holmen Skog?s payment model from per hour to per metric ton for ballast hauling.
The aim of this study is to improve the economic efficiency of Holmen Skog?s ballast hauling in construction and maintenance of forest truck roads. This is done by formulating and evaluating a proposal for a payment model based on crowns per ton.
Fågelbär (Prunus avium L.) - överlevnad, höjdutveckling och skador i unga planteringar på småländska höglandet :
Plant survival, plant damage and height growth were studied in nine wild cherry (Prunus avium L.) plantations in southern Sweden established between 2000 and 2002. All stands were located to the county of Småland. The survey was conducted during May and June in 2007. During the survey the height, diameter and quality of the cherry trees were recorded. In one stand, red ? berried Elder (Sambucus racemosa L.) was a dominant species.
Effekt av gödsling och gallring på mö?belvirke av furu
This thesis is about the effects of fertilizing and thinning on furniture timber from redwood. Interviews of furniture manufactures have been made and observing of timber from the Swedish fertilizing and thinning trails. The result from the interviews showed which properties that is important for the furniture manufactures and then the result from the observation showed which type of management of the forest that gave the most timber that had those properties. .
Analysis of eucalyptus plantations on the Iberian Peninsula
This thesis analyses the prerequisites, profitability and competitiveness of eucalyptus plantation on the Iberian Peninsula and in Brazil. The thesis has a macro perspective and analyses a typical hectare of eucalyptus in each studied region.
A survey methodology was used as a strategy to cover a broad perspective using expert respondents.
The regions studied on the Iberian Peninsula were the ones found suitable for eucalyptus plantations from an economic point of view. The studied regions were Huelva in the South West of Spain, Galicia in the North West of Spain and Portugal.
Stamräkning och identifiering av åtgärdsbehov i röjnings- och gallringbestånd med hjälp av låghöjdsbilder
This report is an assessment of the feasibility of using aerial photographs to estimate number of stems per hectare in young forest stands, used together with upper height to determine the need for pre-commercial thinning or ordinary thinning cutting. Aerial photo-interpretation was conducted in 2007 on assignment of Stora Enso Skog AB. A mean height function based on stand age produced with data from Bergvik Skog AB?s 2006 forest inventory assessment was used as a proxy for upper height and used together with photo-interpreted number of stems per hectare to determine the need for thinning cutting according to Bergvik Skog AB?s definitions. The test area is located north of Falun on Bergvik Skog AB?s land.Flight altitude was approximately 900 m above ground and the aerial photos were taken by L&L Flygbildteknik AB.
Stormskador i lärk och gran : en jämförelse efter stormen Gudrun
The storm Gudrun January 8-9 2005 felled about 70 millions cubic metres forest in southern Sweden. The majority of the wind damaged forest was spruce (Picea abies). In order to decrease the risk of wind damages in the future other trees species are of interest for forestry in southern Sweden.
The purpose of this master thesis was to study if larch were more wind tolerant than spruce. The method was to compare larch, Japanese larch (Larix kaempferi Lamb.), European larch (L.
Underröjning i förstagallring :
This report is a thesis work for a B.Sc. in Forestry exam at the School for Forest Engineers,
SLU. The work was an assignment from Sydved and the aim of the work was to investigate the economical output of removing understorey trees before first thinning.
Four treatments were studied.
- no cleaning before thinning
- cleaning of all trees less than DBH 5 cm before thinning
- cleaning of all trees less than DBH 7 cm before thinning
- cleaning of all trees less then DBH 9 cm before thinning
The result shows a decrease of the cost per m3 for the harvester with about 38% if all trees less than DBH 9 cm was cleaned before thinning compared with the un-cleaned area. At the same time the total net revenue increases with about 22%.
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Effekter av gödsling i äldre tallbestånd på renbetesväxter i fält- och bottenskikt :
Reindeer husbandry and Forestry are both area related industries and will in big extent use the same lands. Conflicts often arise because of that the industries have different interests. Many of the activities done by the forestry influences the reindeer husbandry in an undesirable way, simultaneously as the reindeer husbandry activities can have negative consequences for the forestry. One such forestry activity is fertilization.
It was during the 1960´s forest fertilization began to be practiced and the reason was that the increase in growth that the fertilization gave could be able to cover for the future shortage in wood many feared.
During the 1970´s when the fertilizing activities were most intensive about 200 000 ha was fertilized annually.
Kolbalansen vid olika skötselstrategier för skogen på Tagels fastighet.
Since the 19th century the concentration of CO2 in the atmosphere hasincreased by 40 percent as an effect of the use of fossil energy sources.Increased concentration of CO2 will likely lead to increased temperature,changes in precipitation, rising sea level and increased frequency of extremeweather like storm events. A step to reduce emissions of CO2 and mitigateclimate change, for the property of Tagel, can be to adopt new silviculturalstrategies and analyse which is the most effective. As a result of that, threescenarios was produced, business-as-usual (BAU), increased set aside landand energy. An introduction of windpower at Tagels estate (property) andeffects on carbon balance was also examined. By using the Heureka systemand LCA-analysis in this study, it showed that the scenario of increased setaside land was the most efficient way to reduce carbon dioxide (CO2)emissions for the analysed period of 100 years.
Löpmagsförskjutning hos mjölkkor : en besättningsutredning för att identifiera riskfaktorer för metaboliska störningar
The purpose of this study was to find possible explanations to why the studied herd had an increased incidence of abomasal displacements. The incidence of abomasal displacement in the herd was three times higher than the incidence of an average Swedish herd. The cows in this study were fed a total mixed ration. The different parameters studied were: energy content in food, nutritional content in food, body condition scoring, concomitant other diseases, and blood parameters of glucose, fructosamine, cholesterol, insulin, betahydroxybutyrat and free fatty acids. The author?s suggestions to decrease the problems are to decrease the energy content in the TMR to lower the cows? body condition scores in the dry period and changing the content in the TMR to increase the amount of NDF and adding structure in the form of chopped straw.
Hur kan blöt vetedrank lagras, hanteras och utfodras till mjölkkor? :
Distillers? grain is a by-product of ethanol production. Corn, wheat and barley are the grains
that are generally used in the distillery process. Distillers? grain is rich in protein and
phosphorus.
Elevperspektiv på ämnet historia
Abstract
The purpose of this study is to further understand swedish highschoolstudents perspective on the subject of history. In order to produce an answer a series of qualitative interviews were conducted with six students of mixed ages, ethnicity an gender. Their answers were evaluated using relevant didactic theories focusing on the use of history, historical consciousness as presented by Klas-Goran Karlsson. Motivationtheories according to the RISE model. By Edward Hootstien.