I Sverige gallras årligen ca 360 000 ha skogsmark. Skogsbolagen efterfrågar effektivare skogsmaskiner för att minimera kostnaderna i skogsbruket. Två finska och en svensk studie pekar på produktivitetsökningar i storlekar upp till tio procent vid användandet av griptilt. Griptilten är en tilläggsmodul som monteras mellan gripen och rotatorn på en skotarkran och möjliggör uppresning av virkesknippen till vertikal position. Syftet med studien var att mäta om det blev någon effektivitetsskillnad för krankörningsarbetet under lastning av en skotare, med och utan griptilt i gallringsbestånd med tre olika beståndstätheter: 1000, 1500 och 2000 stammar/ha. Studerade faktorer i bestånden var ackumulering och jämndragning mot mark.

Growth models are very useful tools for forestry to predict growth and yield. With growth models and optimising tools you can manage forest stands in a way that maximize benefit and income. There are three major types of growth models. Stand models; stage structured models and single-tree models. The most advanced models give the most accurate forecasts.

The aim of the study was to compare productivity in first Thinning of birch stands, when either energy- or pulpwood was harvested. The systems total profitability was also compared by including forwarding and chipping costs. A Gremo 950 HPVR harvester was used and the same driver was used under the entire study. During the pulpwood harvest a Logmax 4000b harvester head was used and a feller buncher head made by Silvatec was used during the energy wood harvest. Six study unit pairs were located in a birch dominated stand outside Ängelholm in Skåne.

Röjning är en skötselåtgärd som påverkar det framtida beståndets utveckling och skördeutfall. Olika och delvis motstridiga mål måste beaktas vid röjningstillfället. I praktiken blir många bestånd röjda mer än en gång. En orsak till upprepad röjning är att det kan uppstå behov av förnyad lövröjning när stubbskott har vuxit ifatt barrträden. Röjningens utförande kan också påverka nästa skötselåtgärd, dvs.

Forest fertilization had its peak in the late 60´s, when almost 200 000 ha was fertilized annually. The silviculture of today has high demands for timber production at the same time as the demand for nature conservation increases. It means that it?s necessary to produce more volume in smaller areas in the future. The use of DGPS equipment has in modern forestry in Sweden become more and more common.

The purpose of this thesis work is to evaluate how the physical behaviour of a pipe bend is affected by the pipe bending procedure. Effects such as initial ovalization, Thinning, thickening and plastic hardening from the bending procedure are examined and the mechanical properties of pipe bends containing these effects are investigated.This has been evaluated by creating a detailed Finite Element model of a pipe that is being bent. Then the differences compared to a bent tube in a virgin state, so called Elbow elements and an analytical in-house program have been evaluated. The virgin state refers to a model of a pipe that is bent from the beginning, thus having a homogeneous thickness and not containing any plastic hardening. The Elbow element is a calculationally cheap element, specially developed for accurate calculations of pipe bends in an initially virgin state.The goal with the thesis work is to get a better picture of what happens to a pipe as it is being bent, how this affects the mechanical properties and to evaluate the possibility to develop an easy method for taking these effects into account when using the Elbow element.This report describes the layout of the work and how the detailed FE-model has been constructed.

The Lodgepole pines susceptibility to Heterobasidion spp. was investigated in three parts ofthis study. In the first part, discs from freshly cut stumps were collected and analyzed to seeif the fungi can spread and grow naturally in Lodgepole pine stands. In the second part, rootsamples were collected from Lodgepole pines planted in former infected Norway sprucestands to see if the fungi can spread through root contacts. For the third part, new stumpswas created and artificially infected with spores of both the S?type (H.

This thesis analyzes the effects of different fertilization strategies on forest management at Holmen Skog in Umeå district. Harvesting volumes, net present values and fertilization intensity are presented for each fertilization scenario. The planning reserve (percentage area older than minimum final felling age) was also analyzed in this study.The thesis covers the analysis of five different fertilization scenarios, varying in fertilization intensity, from no fertilization at all, to fertilization at every harvesting operation (Thinning or final felling). A sub-study was also carried out so the reader in detail can see how the different fertilization scenarios affect individual forest stands of different nature. The analysis has been done with the planning tool PlanWise, which is an application of the Heureka analysis and planning system.

The purpose of this thesis work is to evaluate how the physical behaviour of a pipe bend is affected by the pipe bending procedure. Effects such as initial ovalization, Thinning, thickening and plastic hardening from the bending procedure are examined and the mechanical properties of pipe bends containing these effects are investigated.This has been evaluated by creating a detailed Finite Element model of a pipe that is being bent. Then the differences compared to a bent tube in a virgin state, so called Elbow elements and an analytical in-house program have been evaluated. The virgin state refers to a model of a pipe that is bent from the beginning, thus having a homogeneous thickness and not containing any plastic hardening. The Elbow element is a calculationally cheap element, specially developed for accurate calculations of pipe bends in an initially virgin state.The goal with the thesis work is to get a better picture of what happens to a pipe as it is being bent, how this affects the mechanical properties and to evaluate the possibility to develop an easy method for taking these effects into account when using the Elbow element.This report describes the layout of the work and how the detailed FE-model has been constructed.

This thesis analyzes the effects of different fertilization strategies on forest management at Holmen Skog in Umeå district. Harvesting volumes, net present values and fertilization intensity are presented for each fertilization scenario. The planning reserve (percentage area older than minimum final felling age) was also analyzed in this study.The thesis covers the analysis of five different fertilization scenarios, varying in fertilization intensity, from no fertilization at all, to fertilization at every harvesting operation (Thinning or final felling). A sub-study was also carried out so the reader in detail can see how the different fertilization scenarios affect individual forest stands of different nature. The analysis has been done with the planning tool PlanWise, which is an application of the Heureka analysis and planning system.

A third party access to district heating networks has been proposed in Sweden, to increase the competition on the district heating market. Such third party access could create opportunities for the agricultural sector as an energy producer. This study describes the technical, economical and environmental prerequisites for a farmer cluster to build and run a heating plant, fueled with local wood fuel. The heating plant in the described scenario is 8 MW and will supply a village of 1000 houses, and is fueled with wood chips exclusively. Supplying a heating plant with fuel puts high demands on the logistics, since there need to be a continuous flow of fuel. In the scenario, wood residues from felling and Thinning is stored in stacks in the forest, and a few times a year chipped and transported to a storage area at the heating plant. In the study, an estimation of the profitability has been made by estimating the cost of the investment, personnel, operating and maintenance costs and costs for the fuel and ash handling.

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.

Bergvik Skog is one of the leading forest companies in Sweden who use airborne laser scanning for forestry information. They utilize laser data retrieved by the Swedish National Land Survey to describe the forest holdings and facilitate planning for Thinning and final felling operations. However, the possibility to identify stands with clearing needs by using laser scanning data has not been tested in a large scale. The data used in the current study are field data from The Swedish National Forest Inventory in combination with laser data from the Swedish National Land Survey acquired in 2009. The collected data is used to find one or several laser variables that best describe the relationship of the field measured samples with clearing needs.

This work broadly illuminates the conditions for increasing the commissions of forestry services within the whole, or parts of, the western regions of Stora Enso?s operating area. Through a questionnaire, a survey was made examining whether the owners of the forests themselves do the forestry on their woodlands. This foremost concerns the pre-commercial Thinning, but also planting and soil scarification. The survey also shows who are buying the most part of their forestry services and who are carrying it out themselves.

The supply of raw materials has always been an important issue in the Swedish Forest industry. Buying timber from local suppliers is important. To ensure raw materials to their industries the forest company must offer good prices and good business deals to their suppliers. The aims with this work are to find out how the contact between private suppliers of raw materials and how the forest company can be developed. To be able to do a complete study of the problems connecting with this subject a quality interview study has been done.