According to the Board of Forestry, in Västerbotten, many natural regenerations of Scots pine (Pinus sylvestris) carried out on privately owned forest in the middle of 1990 in Västerbotten have rendered a bad regeneration outcome and will provide a low future forest production. The Board of Forestry believes that the negative result can be explained by the fact that the regeneration has been carried out in wrong locations and that scarification failed to work as planned. In order for an accepted rate of regeneration the guidelines of the Forrest Act require, not less than 10 years after final cutting at natural regeneration, that there should be at least 1300 (site indices 16 m) - 1700 (site indices 20 m) main crop stems per hectare. Main crop stems are defined as stems according to the place of growth and appropriate tree type, in addition with regard to quality, stage of development and damage risk have a prospect of succeeding. In addition main crop stems should be separated by surface so that the proportion sample plots with 3 meters radius, and lack main crop stems, are not more than 10 % of site indices 14 meters or higher.

A lot of habitats have declined or disappeared as the old cultural landscape changed to the modern agricultural landscape of today. Places such as power line corridors, racing tracks, gravel pits and military training sites have become refuges for many species associated with the old cultural landscape. These sites have been exposed to ecological disturbances that create the same type of habitats that were found in the old cultural landscape.The military training sites in Sweden has an impressive diversity of species. Disturbances from the military exercises have created habitats that are important for a wide range of species.The purpose of this thesis is to study some of the ecological disturbances occurring in the military training sites of the Swedish Armed Forces and examine how they affect different types of habitats. The thesis explains through litterateur and field studies the reason to the rich biodiversity often found at military training sites.

The ammonia emissions are an environmental issue since they contribute to eutrophication. By far the largest source of ammonia emissions is manure from agriculture and should therefore be reduced. Loss of ammonia is not only negative for the environment but also to the farmer who loses nitrogen that could have been used by the crop. The focus of this study has been emissions from spreading slurry where the loss can vary widely depending on slurry-, soil-, and weather conditions. There are mainly two different ways to reduce the emissions. One is to inject or mix the slurry into the ground to avoid air contact. The other way is to use acid to reduce the pH in the slurry to a level between 5 and 6 where the equilibrium is so strongly pushed to NH4+ that hardly any NH3 can be lost.

AbstractThis essay discusses different explanations and interpretations of what characterizes large areas containing clearance cairns (cairn fields). Results from the analyses show that there are different explanations about when and why cairn fields and clearance cairns occur. Explanations vary from introduction of the wooden ard in the early Bronze Age to the introduction of rational hay-making in the Roman Iron Age.  There is, anyway, relative agreement considering why and when cairn fields were abandoned. The reason suggested is an increasing pasturage with the consequence of reducing soil to poverty during the period of the Great Migration or in the Viking Age.The most likely cultivation system in cairn fields is a system consisting of both intensive and extensive characteristics. The latter coincides with the probable mobility of settlements.

Allanblackia is a tree genus native to humid forests in West, Central and East Africa. Its fruits contain large seeds from which edible high-quality fat can be extracted. In order to create a sustainable supply chain of Allanblackia seeds, a domestication program has been initiated with the purpose to enable smallholder farmers to grow the tree as an agroforestry component and cash crop. More knowledge is required to understand the tree?s biology and possible symbioses involving soil microorganisms with plant growth enhancing poten-tial.

A secondary and a pioneer tree species can with advantage be included in a mixed stand to increase the use of sunlight. Nitrogen-fixing plants have been shown to increase the supply of nitrogen in the soil by, for example, litter fall. This deposition acts as a biological fertilization, which may be used by non-fixing plants. Alder is a nitrogen-fixing, pioneer tree species that loses its nitrogen-rich leaves late in the autumn. The aim of this study was to examine the effect on the total volume of production, when different proportions of nitrogen-fixing Alder were part of spruce stands.

The Department of Forest Products and Management, Swedish University of Agricultural Sciences has received means from Vinnova for a preliminary study of the organisation of logging work of today and how a better logging organisation should be brought about. This thesis reports results from qualitative interviews with nine forest machine contractors regarding the situation of their companies. The interviews have been analysed with respect to the genesis of the companies, which tasks they perform or that they could consider perform-ing, business relationships of the companies, relationships between the different partners of the companies, and the state of competition experienced by the contractors. The companies have developed either from the contractor previously being machine operator employee or from that the contractor in making has owned a machine and needed work. Their primary business is mechanised logging.

The aim of this study was to investigate and describe conceptions that been used when people talks about grapples and to put together parameters that the customers sees as important when they chose a grapple from Hultdins. Every year Hultdins manufacturer and sells about 3500 grapples around the world. With so many users its difficult to oblige everyone. To get an apprehension of what kind of grapple the operators wanted a formula with 18 questions was made. For the interviews 20 forestmachineoperators were choicest who had experience from Hultdins grapples, a lot of them also had experience from other grappleproducers and constructions. The study showed that it is the durability the users give priority to.

The aim of this study was to map the prevalence of aeolian sand dunes in Västerbotten, northern Sweden to find dunes formed during earlier deglaciation phases, which was then preserved in cold-based conditions during the youngest stadial of the Weichselian glaciation. These preserved dunes were expected to be covered by a layer of till and have a rather faint morphology compared to dunes formed during the Holocene. Consequently, high resolution LIDAR-derived images from the Swedish mapping, cadastral and land registration authority (Lantmäteriet) was used to detect the dunes throughout an area covering most of Västerbotten, above the highest coastline and below the mountain range. The analysis resulted in several new findings of aeolian dunes compared to the findings in the quaternary soil map created by the Geological Survey of Sweden. Despite the fact some of the dunes at the LIDAR-derived image had a strange faint appearance, it was quickly evident during the fieldwork that the aeolian sand was not covered by till on any of the dunes visited.

Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off.

Femsjö is a small parish situated in Hylte municipality, Växjö diocese. The parish has a total area of 8230 ha of which 5000 ha are covered with forest. There have not been any large industries in the parish offering work opportunities for the inhabitants, so they have had to generate income from their land and the forest. Instead of going to the bank to get a bank loan the people of Femsjö parish went out in to the forest and harvested trees for timber and extra cash revenue. Production of pine tar and potash were two other ways that the residents of Femsjö parish could earn extra money for the household in order to keep starvation away.

Due to soft grounds in combination with seasonal variation in soil humidity, there is a lack of stands that are possible to cut during spring and autumn in some geographical regions. For Holmen Skog this sometimes means that a large proportion of the contracted private forest is cut during the winter when the ground is frozen. One consequence of this is that the proportion of winter stands in the stand bank of own forest increases while spring and autumn stands becomes a scarcity. This in combination with milder winters, especially when there is a long period of reduced bearing capacity in spring or autumn, means that the situation rapidly can become critical. The overall goal with this study was to generate basic data for decision support in the work to achieve a sustainable distribution between own forest and contracted private forest in the stand bank. The study took place at Holmen Skog, district of Umeå, during autumn 2007 and was based on interviews and an analysis of harvest planning and delivery data. The study showed that there is a problem with how the cutting is distributed between own and contracted private forest during the year and that it foremost is the proportion of winter thinning of own forest that has increased in the stand bank.

Syftet med denna uppsats är att undersöka hur olika potentiellt skadliga faktorer påverkar nyetablerade stadsträd. För att göra detta utvecklas en metod för inventering av träd och ståndort, som sedan appliceras på ett urval på 94 stadsträd fördelade på 11 anläggningar i Uppsala och Stockholm. Faktorerna som framkom som resultatet av studien jämförs med skadliga och gynnsamma faktorer enligt uppgifter från trädexperter och litteratur. Uppsatsen inleds med en beskrivning av stadsträds situation idag och historiskt, samt nuvarande kunskapsläge. Därefter följer ett metodkapitel som beskriver metodutvecklingen. Metoden bygger på inventering och analys av ett antal punkter. Exempelvis behandlas vilken information stamomfång kan ge och hur det inventerats under rubriken Stamomfång.

Applicering av överlast på kalkcementförstärkta jordar är ofta förekommande idag, forskning indikerar dock på att överlasten här, inte ger samma effekt som på oförstärkta jordar. Med grund i uppmätta värden i fält, visas i denna rapport, sättningsdifferenser mellan att använda överlast jämfört med att endast applicera brukslast. Resultat av analyserna visar på sättningsbeteende observerat i fält. Om erforderlig liggtid för brukslast finns, uppstår endast små sättningsdifferenser mellan att använda överlast eller inte.Genom att utföra sensitivitetsanalys i FEM- programvaran PLAXIS studeras kryputvecklingen i den förstärkta jorden. Effekten av att applicera en överlast visas för krypsättningar över lång tid.Inget resultat från de numeriska FEM- analyserna visade att märkbart gynnsam effekt uppstår på grund av överlastens applicering, med avseende på krypsättningar.De numeriska analyserna utförs i 2 och 3 dimensioner för att belysa effekt av förenkling av ett lastfall som inte uppfyller krav för oförstärkta jordar i plant töjningstillstånd.Utöver detta ges efter en litteraturstudie, förslag på hur vissa indataparametrar kan utvärderas från empiriska relationer.

The purpose of this report is to examine the possibilities to decrease the number of insects and other pathogens in a crop of pak choi (Brassica rapa), grown with different types of cover and living mulches. Included in the report is a study of literature where amongst others, a summary on the vegetable pak choi and theories of living mulches and different kind of covers are to be found. To examine the amount of predators in the field, traps were used. During the autumn 2002 the tests were conducted in Alnarp. The pak choi and the living mulches were planted/sawn at the same time, the different covers were also applied at this time. The total experiment was divided into six different treatments (plus control) of which three were with covers and three were with living mulches. Once a week the number of leaves, the height and damages were read on ten of the plants from each parcel.