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437 Uppsatser om Tree rings - Sida 3 av 30
Laserdata i skogsbruket : - och möjliga tillämpningar för privata skogsägare
Data retrieved from airborne laser scanning represents a new source of forest data. Today, the technology has matured so that it can function in an operational environment. The aim of this study was to compile areas of application of laserdata in forestry. Moreover to analyze costs and accessibility of laserdata. The goal was to provide private forest owners information to support assessments of possible benefits of laserdata.
Skötselns och ståndortens betydelse för kärnvedsbildningen i tall
Heartwood has always been a desirable part of the tree, due to it?s superior decay qualities com-pared to the sapwood. How the formation of heartwood works has been known for a long time, but which factors that initiates and stimulates the production are poorly understood. This case study presents the results of a study in which silvicultural treatments and site properties had a key position as factors to the formation of heartwood. According to the hypothesis the amount of sapwood is directly controlled by the size of the crown.
Examination of mycorrhizal associations of Allanblackia stuhlmannii : a tree under current domestication
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.
Hyggesbränning på Orsa besparingsskog - en studie på tillväxt och föryngring,15år efter etablering
The main purpose with this study was to investigate whether the tree growth differs or not in prescribed burnt areas compared to mechanically scarified. Together with the result from the main purpose, answers of whether it's possible or not to combine nature conservation with tree production in prescribed burnt areas was presented. In these areas the regeneration were analyzed to see if there was enough tree plants to comply with the Swedish Forestry Act regulations terms for approved regeneration. A field survey was conducted at 6 objects, three objects for prescribed burning and three for mechanically scarification. All objects were planted within the same year.
Provtagning av trädkärnor för att bedöma föroreningsgraden av klorerade lösningsmedel i grundvatten
Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons.
Tree species traits response to different canopy cover for 34 tree species in an enrichment planted tropical secondary rain forest in Sabah, Malaysia
Tropical rain forests only cover around six percent of the world?s land area and contain around 70 % of the world´s animals and plants. Tropical rainforests have been, and still are, negatively affected by human activities. These activities lead to forest degradation which has negative impacts on production and biodiversity.
Between 1970-1980 forests in Borneo, Sabah, Malaysia, was subjected to intense logging.
Vindfällning i naturliga och skapade bryn och kanter :
The aim of this work was to study if the edge of the forest is more resistant to heavy winds than the trees located further in from the edge, and how this edge effect changes between different types of tree species and site types.
The data was collected from an electric power line going from the north to the south of
Sweden. The mean value of the clearcutted area around the power line was 120 meters. The
main direction of the storm in January 2005 was west-southwest and thus the power line was a perfect place for gathering a large data set.
The main parameter studied was the damage frequency at the edge of the forest compared to
the trees located further in from the edge (up to 100 m from the power line). Tree species mixture, soil moisture class, soil type, topography, stand height, stand height of the stand on the other side of the power line and wind exposition was estimated.
The results showed a distinct edge effect. The edge of the forest had clearly lower damage frequency for all tree species.
A marked difference was observed between tree species and damage frequency.
Vedrötor i stadsträd : biologi, detektionsmetoder och förebyggande åtgärder
Urban trees have very little in common with trees on natural sites, such as forests or pastures. Trees in urban environments are often planted in packed soil and in small volumes. This can lead to decreased availability of water and oxygen, as well as deteriorated ability for the soil to store nutritional elements. Also above ground the tree usually have limited space in cities. Regulations on free height over roads and cycle tracks demands high stems at an early stage of their development.
Mätning av stamdiameter med markstående scanner :
Booth for operational planning of harvesting and for long term planning, data is today collected manually. Intensive objective field inventories are usually too expensive. To enhance optimisation of timber flow from forest to industry Moore efficient methods for measuring tree stems of standing trees are needed. The performance of terrestrial laser scanners have improved and these could possibly be used within forestry in the future. The objective of this study was to validate how a terrestrial laser scanner could be used to measure stem diameter, and to test how the errors depend on distance from the scanner and tree species.
Two plots (one pine and one spruce) were used for this study.
Filmernas kristna Midgård : En undersökning kring Sagan om ringen-filmernas kristna motiv
Syftet med denna uppsats är att försöka finna de kristna motivens plats i berättandet i de tre Sagan om ringen-filmerna (The Lord of the Rings) av Peter Jackson. Arbete har lagts ned på att studera litteratur inom både religion och filosofi kring filmernas Midgård-berättelser, där dessa behandlar kristna motiv. Den etablerade forskningen kring detta ämne har hittills till stor del handlat om Tolkiens böcker och inte i särskilt stor utsträckning om filmerna. Därför kan uppsatsen anses relevant i en tid där filmen mer och mer ses som lika betydelsefullt medium som boken.Det resultat som har nåtts är att det förefaller vara en stor del av filmernas handling som har sitt ursprung inom kristendomens berättelser och motiv. Detta inte bara i filmernas stora och övergripande berättelse (i synnerhet berättelsen om Frodo och Sam) utan även i sidoberättelserna (särskilt de som berättar om Aragorn och Gandalf).
Kostnader vid gallring med flerträdshanterande aggregat, från skog till industri
Profit in first commercial thinnings of today is hard to achieve. This is because of prevailing pulpwood prices and because of high costs of logging and transport. To reduce these costs higher productivity is advocated. One way to increase the productivity is the use of multi-tree handling harvester heads. The aim of this study was to calculate logging and transport costs in first thinnings, where multi-tree handling has been used.
Nya träd för stadsmiljö
Trees in urban environment are exposed to extreme conditions, foremost the ones that grow in the hard packed soil along our streets. They are also exposed to damaging insects and fungal diseases both local and new ones spreading from South Europe. The global warming with warmer temperatures provides a longer growing season, making it easier for insects and fungus to establish a habitat. Based on these facts new tree species need to be available for future urban plantings.To determine what these trees would be an interview study began. Six people were selected who have experience in the field of urban environment planting.
Nyckeltal för älg och fodertillgång på tall Pinus sylvestris och rönn Sorbus aucuparia
It has been shown that moose can affect plant community composition and structure. Selective browsing with other damages of large herbivores on tree species with different tolerance to disturbance could reshape the tree layer in both managed and natural forests. Rowan Sorbus aucuparia is widely distributed throughout Sweden and Europe. Research has shown that browsing by moose may prevent rowan from reaching browsing safe heights. The goal has been formulated that, where rowan is indigenous, it should have a good competition status and be able to reach tree level.
Skogsbränsledrivare i klen förstagallring med contorta
The aim for the study was to examine a harwarder´s (combined harvester-forwarder) productivity when harvesting forest fuel in first thinning stands that contains Lodgepole pine and calculate the economy of the harvesting work and estimate the quality of the thinning . The field study area where located near Arvån, about 15 kilometres south ?east from the city of Lycksele. The field studies were taken place in three different stands. All tree stands had the same tree age, but the tree species combination and the density varied.
Optimering av testning av säkerhetskritiska funktioner
Inom industrin används olika testmetoder för att uppnå hög kvalitet i mjukvarukontrollerade system. Kvalitetskraven är särskilt höga för säkerhetskritiska system t.ex. styr- och reglersystem i fordon. I det här examensarbetet används två analysmetoder (Fault Mode and Effects Analysis och Fault Tree Analysis) för att ta fram ett nytt säkerhetstest för ett broms- och växlingssystem som Scania tillverkar. Det studeras även hur formella metoder kan användas för att ytterligare öka kvalitet ochh tillförlitlighet.