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402 Uppsatser om Descision Tree - Sida 7 av 27
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.
Retention of stumps on wet ground at stump-harvest and its effects on saproxylic insects
Low stumps represent on their own up to 80% of the dead wood remaining on clear cuts and therefore supply suitable habitat for saproxylic insects i.e. insects depending on dead wood for their survival. Recent stump harvesting activities threaten this substrate of ecological importance and increase the anthropogenic negative impacts on these species. Because of technical and environmental reasons (nutrient leakage, erosion) guidelines for stump harvesting recommend to retain stumps standing in wet parts of clear cuts. However, stumps in wet positions might not be a satisfactory substrate for saproxylic insects and therefore might not be as much used as stumps in dry positions.
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.
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.
Productivity of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) in coastal areas of northern Sweden
Productivity of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) was
studied on 12 sites in coastal areas of northern Sweden. On each site, sample
plots were placed in adjacent Norway spruce and Scots pine stands with similar
ages in between. Basal area, tree height, Site Index, volume production,
simulated maximum mean annual increment (MAImax) and tree vitality were
compared for the two species. Average basal area at the time of measurement
was 30.4% larger for Scots pine stands than for Norway spruce stands. The
difference between the two species in basal area increment during the last 10
years was related to stand age.
Ajuourhållning av ungskogsdata med hjälp av digitala flygbilder :
The purpose of this study is to investigate whether it is possible for SCA to update their stand register with use of digital aerial photos photographed with a Zeiss/Intergraph DMC. ?Updating? in this study implies the delineation of stands and estimating stand variables such as average stand height, volume density, stand volume, and tree species composition in order to identify stands which can be of current interest for thinning.
The study also includes how the aerial photo material and experience of the interpreter can influence the quality of the interpreted variables.
The aerial photo interpretations were made by both experienced and inexperienced interpreters.
A, B, SEE ? 1, 2, TREE : om konsten att se det som är osynligt för andra
Gungstolen är en möbel med en säregen relation till sin brukare. Känsloladdad, lite opraktisk men omtyckt. Jag önskar att fler ska få uppleva glädjen och stoltheten i att bidra till skapandet av en möbel. En träram som fylls med personligheten av sin brukare. Kan detta också göra relationen till möbeln starkare?.
Habitat preferences and reproductive success forthe threatened longhorn beetle Plagionotusdetritus
Plagionotus detritus is a threatend longhorn beetle that only exists at one site in Sweden. It is saproxylic and depending on recently dead coarse oak wood for its larval development. Trees at Djurgården, Stockholm that have been colonized by Plagionotus detritus has been studied to find out the habitat preferences of the species and to see what affects the density of beetles in a tree. The bark of some trees and wood from the breeding project at Nordens Ark has also been studied to find out what affects the species reproductive success. The reproductive success was measured in two ways, the larval mortality and the size of the hatching holes.
Tillväxtreaktion hos skärmträd i högskärm av gran i Medelpad :
Different methods for shelterwood cutting have been used in differ-ent parts of Europe since the middle ages. The use of shelter wood cutting in Norway spruce (Picea abies (L.) Karst.) forests in Sweden met a revival in the early 1990s as an alternative for the dominating clear-cutting system when silvicultural costs increased dramatically for the latter. Shelterwood cutting systems involve some possible problems but also a lot of positive effects. Among the problems are increased risk of wind throw and damage of the remaining shelter trees caused by the cutting operation. Positive effects are for example a valuable growth in the remaining trees and increased biological di-versity.
This study is based on a total of 79 trees from 4 different treatments in a spruce shelterwood, cut in 1994, in the middle of Sweden (62,4º N).
Allanblackia stuhlmannii ? a tree under current domestication: what are the soil requirements?
Allanblackia is a genus of trees that grows in the rainforests of West, Central and Eastern Africa. Its big fruits contain seeds very rich in oil which has been used by
local communities for cooking and making soaps. The native stands are threatened by overexploitation and the demand for the oil is much greater than the supply.
Domestication programs, aiming at introducing the trees to small holder agroforestry systems, have been started for some of the species. The main aim of this study was to investigate the soil requirements of Allanblackia
stuhlmannii in terms of chemical and physical parameters, as revealed by the soil conditions in native stands. Another aim was to see if these varied along an altitudinal transect.
Mångfaldsarbete : En jämförelse mellan privata och offentliga sektorn
The aim of this thesis is to study whether social welfare secretaries experience occupational pride and what affects this feeling. Previously made research indicate that occupational pride is essential for performance and work-related health. Research has also shown that social welfare secretaries often experience unhealthiness due to working conditions and a lack of professional self-esteem.This thesis is based on four qualitative interviews which have focused especially on critical incidents, according to the critical incident technique. This study has a hermeneutic, interpretative approach. As a theoretical framework, Pierre Bourdieu? s theory on social space and positions aswell as Aaron Antonovsky´s theory on Sence of coherence have been used. The result shows that the interviewed social welfare secretaries do experience occupational pride.
Hållbar Textil Produktutveckling : med växtfärgning
Författarna har haft ett samarbete med Panduro Hobby i samband med deras årliga miljökampanj. Syftet med examensarbetet har varit att med hjälp av befintliga produktutvecklingsprocesser och livscykelanalyser (LCA) ta fram en hållbar textil produkt med växtfärgning. Tanken var att konsumenter sedan själva skall kunna ta fram och växtfärga denna hållbara textilprodukt. Miljömedvetenhet och hållbarhet inom textilindustrin är ett aktuellt ämne. Trots det saknar dagens konsumenter förståelse för textilindustrins påverkan på miljön och har bristande kunskap om textila material för att kunna göra miljövänliga val ute i handeln.
Socialsekreterare och stolt? : En kvalitativ studie om socialsekreterares yrkesstolthet
The aim of this thesis is to study whether social welfare secretaries experience occupational pride and what affects this feeling. Previously made research indicate that occupational pride is essential for performance and work-related health. Research has also shown that social welfare secretaries often experience unhealthiness due to working conditions and a lack of professional self-esteem.This thesis is based on four qualitative interviews which have focused especially on critical incidents, according to the critical incident technique. This study has a hermeneutic, interpretative approach. As a theoretical framework, Pierre Bourdieu? s theory on social space and positions aswell as Aaron Antonovsky´s theory on Sence of coherence have been used. The result shows that the interviewed social welfare secretaries do experience occupational pride.