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544 Uppsatser om Tree mortality - Sida 9 av 37
Shooting Target - Konstruktion : Product Development
The shooting sport is one of the most widespread sports in the world and it isbeing practice in most countries. Based on their own experiences, in competition -and hobby shooting, the client M4Solutions found a demand and need for ashooting target that is manufactured in Sweden.The purpose of the project has been to develop, with the help of Marcus Walldén,two shooting targets from idea to finished product. These two shooting targets,Plate Rack Target and Dueling Tree, would each be equipped with a mechanicalresetting system but will in the future have the ability to be provided with anelectronic resetting system.The project from the client was divided into two theses. One of these two, writtenby Marcus Walldén, focused on the tripod parts and the overall design work forboth Plate Rack Target and Dueling Tree. The thesis that is presented in thisreport have focused on resetting systems, the design of protective plates and otherperipherals for both shooting targets.This work has primarily been in CAD environment where design, constructionand development has been given free rein.
Skiktning och strukturell utveckling i unga naturlika skogsplanteringar: :
Multilayered woodland types are an important part of the urban forest. The knowledge how to establish and maintain such plantations are not as deep as other knowledge fields concerning forestry. Therefore this study has looked upon how to achieve multilayered structures in young nature-like woodland plantations. As a theoretical base for the study three different major knowledge culture have been studied that concerns the subject, ecology, forestry and landscape management/design. This three theoretical framework concludes that many natural processes strive in the opposite direction of multilayered structures in their youth.
Site preparation, planting position and planting stock effects on long-term survival, growth and stem form properties of Pinus contorta on southern Iceland
In order to evaluate different afforestation methods for exposed heath lands a field experiment was established in Mosfell on southern Iceland in 1989. The trial comprised six different site preparation methods (control, herbicide application, tree shelters, patch scarification, TTS trenching and mounding). In total 960 container seedlings (1+0) and 960 Nisula roll transplants (2+1) of lodgepole pine were planted. Various planting positions (furrow, hinge, no site preparation (control) and on top of mounds) were tested within the site preparation treatments. This study involves renewed measurements and analyses of the trial.After 19 years the overall survival was 51,7 %.
Lövsuccessioner i sluttningar längs nedre Umeälven :
Secondary deciduous forests, which have their origin in earlier pasture- and meadow-land in slopes along the lower reaches of the Ume river, are thought to contain high nature conservation values, in spite of a relatively low age. The aim of this study was to clarify how factors as historical use, exposition, disturbance dynamics and successional age influences the conservation values in these types of riparian forests and how this can be implicated in the practical work with conservation and management at Umeå municipality. Sample plots were placed in seven stands with a variation of their historical use, exposition, disturbance dynamics and age of succession. Conservation values as structure, tree-regeneration, abundance and composition of vascular plants, amount of dead wood and the abundance of signal-species were measured and registered. The species composition and especially the composition of tree species, differed between forests with different exposition and different historical use.
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.
Tillskottsutfodring av smågrisar under digivningsperioden :
Weaning is one of the most critical events in the piglet production with problems such as growth check and post-weaning diarrhea as a result. The lighter the piglets are when the growth check occurs, the harder they have to get back to normal growth rate. Creep feeding of piglets is used to reduce the problems by increasing the weaning weight and adapting the digestive tract to a starter diet. Hodge (1974) showed that the sow?s milk can not provide enough nutrients for maximal growth rate.
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?.
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).