Interference in an ecosystem means a disturbance. When harvesting, forest roads have to be build to cope with heavy duty vehicles. Crossing brooks can not always be avoided. In this case bridges or culverts have to be built. There are many different kinds of culverts and depending on what type you choose and how you place the culvert, the watercourse and the water organisms can be harmed in different ways.

Syftet med denna studie var att utreda hur röststyrning kan användas för kontroll av aggregatet på en engreppsskördare. För att studera röststyrning genomfördes en så kallad Wizard of Oz-studie. Metoden går ut på att en människa ersätter en funktion i ett system som ännu inte finns eller är färdigutvecklad. I studien var det röstigenkänningen och inmatningen av korrekt respons som utfördes av en människa, trollkarlen. Rollen som trollkarl utfördes av en före detta skördarförare som numera arbetar som forskare på Skogforsk. Studien genomfördes i Skogforsks skogsmaskinsimulator. I den kan en försöksperson på ett verklighetstroget sätt arbeta med en engreppsskördare.

Vid gallring med normalstora skördare och skotare används vanligtvis noll, ett eller två beståndsstråk mellan stickvägarna. Arbetsmetodiken har studerats empiriskt, men med en begränsad omfattning per studie. Fördelen med simulering som studiemetod är att man med bra modeller över maskiners prestation kan jämföra flera gallringsmetoder vid inverkan av en stor mängd olika förhållanden. I denna studie har en matematisk prestationsmodell konstruerats för deterministiska jämförelser av dessa metoders drivningskostnad i förstagallring av tall. Modellen innehöll en spatial del för skördaren, med bl.a.

The most predominant method for forest harvesting in Sweden is the cut-to-length method based on two-machines, a Harvester that fells trees and cut them in a predefined length, and a forwarder which transports logs to a landing area for further transport to a processing facility. New machine solutions have to be much gentler to the ground than today?s machines. To be able to develop a forestry machine that preserves the terrain requires a proper understanding of the interaction between tire and soil.The goal of the project is to contribute to the existing knowledge of forest machine tire-soil interaction and to develop a tire-soil model that enables dynamic simulations of forest machines operating in rough terrain. The modeling has especially been focused on the interaction between tires and soft ground.A comparison of theoretical data of different WES-based terrain interaction models and a comparison test data from a full scale field test is presented.

The costs of logging and of transportation with truck are dominating the total cost of wood delivered at industry. To support the profitability for the members' forestry the processing and handling with the timber has to be as efficient as possible. Increased length of pulpwood in thinning is one conduct that can result in higher productivity and/or lower costs. The study is scaled as a system analysis with the aim to exemplify the differences between working with 3- and 4-meter as standard length of pulpwood, related to biological aspects, timber receipts, cost of logging and cost of transportation with truck. Important aspects are if the change is technically and biologically feasible and economically profitable.

The efficiency of the Harvesters work is more often reviewed, than the work of the forwarders. In a local Stora Enso office the differences between the Harvesters reported volume of timber, and the actual volume delivered to the industry had been noticed. Therefore, the decision was made to do a review on the forwarders work. The review was conducted together with a worker from Vmf Qbera, who is working daily with wood measurement, in order to get a valid evaluation of the logs. Eight sites were included in the survey, and on each site 50 logs were marked. Approximately one third of the marked logs were pulpwood, and the remaining logs marked were timber.

Hemp is an annual energy crop that fits very well in Swedish crop rotations. It is an interesting crop with many benefits, for example its ability to establish a large quantity of biomass in one year. Hemp is easy to grow and out-competes unwanted weeds through its aggressive growth pattern without the need for pesticides. Interest in growing hemp and other energy crops is currently decreasing, apparently because of high grain prices. These high prices give a higher net profit that we believe could partly cover the cost of hemp cultivation, while the hemp in turn would improve the crop rotation and thus repay its debts in the form of increased yields of other crops. The great disadvantage of hemp is the lack of knowledge about spring harvest of the crop.

The competition for Norway spruce pulp wood in Central Sweden increases, forcing the supply-structure of Holmen to face two important challenges. Firstly, it is of the outmost strategically importance to secure the long-term supply of Norway spruce pulp wood to the industries. Secondly, Holmen desires to increase the obtainable volume of Norway spruce pulp wood. This would enable the company to choose volumes in the lower price-segments and thereby decrease the dependency of costly marginal volumes. As this work shows, one part in managing these challenges could be to lower the quality standards concerning root rot (Heterobasidium annosum). Facts presented in the work shows that: 1. Technically, the TMP-industry of Braviken can handle a much more rotted pulp wood than that used today, although the cost of refinement increases.

GIS i kombination med GPS börjar användas allt mer i det moderna skogsbruket och då främst till traktplanering och inventering. Tidigare försök har visat att utrustningen även kan användas som navigeringshjälpmedel i skördare. Siljansfors försökspark har under en tid koordinatsatt försöksytor med hjälp av en DGPS mottagare och lagrat detta i ett Geografiskt Informations System (GIS). De vill nu se på vilket sätt denna geografiska information kan användas tillsammans med en GPS i en skördare för att hitta och skydda deras försöksytor. Detta examensarbete syftar till att undersöka hur noggrant en skördarförare kan gallra intill skyddsvärda objekt, endast med GPS och digitalt kartunderlag som hjälpmedel.

A recommendation for stand treatment of lodgepole pine (Pinus contorta) is, in a scientific point of view, lacking when it comes to harvesting for biomass energy. Within the next decades it is expected that 280 000 hectares of lodgepole pine will have reached thinning age on the domains of Svenska Cellulosa Aktiebolaget (SCA). Due to this the interest has grown rapidly for studying the possibilities of harvesting biofuel assortments already in the first thinning. In this study the distribution of the biomass within lodgepole pine trees has been studied and taken into account for estimating the proportions of harvested assortments when using different methods of thinning. The methods studied were conventional biofuel-harvesting (with delimbed branches gathered separately from the round wood) and thinning with cutting of round wood and long tops (incl.

The biodiversity of the Swedish forest has degenerated since the beginning of the 19th century when fire suppression and large scale logging first occurred. Together with a changed land use, these actions today have had a negative influence on many forest dwelling species, due to gradual reduction of natural processes, successions and different structures from the forest ecosystem. The Swedish Forest Act, together with different environment certifications, have today encouraged private persons and forest companies, among them Holmen Skog, to work actively to improve nature conservation. The aim of this study was to, by field inventories of already existing nature values, literature studies, recommendations from scientific reports and ecological gap analysis as a basis, make a management plan, for a non-production area, to conserve or improve the prerequisites for biodiversity. ?Storskogsberget? is located in the coastal area of Västerbotten County, 35 km from the city of Umeå.

Forest enterprises have always searched for ways to improve efficiency. For the past few years there has been an emphasis on stock-keeping levels. Increased demand for fresh round timber and the need to decrease the amount of tied-up capital has made the forest industry reduce its inventory levels. This has brought on a higher demand on the timber supply from the forest management districts concerning both delivery in time and assortment output. As a result, the flow of timber has fluctuated a lot with serious consequence for the timber supply during 1994.