The aim of this study was to evaluate different types of volume and taper equations that can be used to predict Single-tree stem volume and stem diameter at any given height along the tree stem for plantation grown Sitka spruce (Picea sitchensis (Bong.) Carr.), Norway spruce (Picea abies (L.) Karst) and White spruce (Picea glauca (Mounch) Voss) in Iceland. A number of published tree volume equations were tested and modified to predict the total stem volumes over bark but three logarithmic equations were taken for more in-depth analysis. Three taper equations were tested. Two variable-exponent equations (Kozak 1997, Kozak 2004) and one exponential equation described by Biging (1984). Data from a total of 617 sample trees were used in this study, collected from stands in various parts of the country and present different types of stands growing in different soil types and cover most of the site conditions suitable for forestry in Iceland.

The aim of this study is to describe a number of type stands of lodge pole pine in Norrbotten with respect on stem volume and total biomass. Further questions to answer is if there is stand characteristics that make the stands more suitable for pulpwood in early thinning, or if it is better to apply whole tree harvest. The study shall also give an indication if bio energy can be an economical interesting alternative for Sveaskog. Sampled trees represented the variation in the different stands. Five trees were selected from each stand to represent that stand. Stem volume and biomass (kg dry weight (DW) per hectare) for each fraction was calculated.

The aim of this study is to investigate how multiple tree handling harvesters perform compared to earlier developed standards. The study shows that multiple tree handling harvesters are more efficient in thinnings stands with mean stock volumes less than 0,12 m3fub per stock. The increased efficiency is different for different mean stem classes. In stands with a mean stem volume of 0,04 m3fub per stock, the increase can be as high as 40 percent while it is about 10 percent in stands with a mean stem volume of 0,12 m3fub. Comparisons have been done between stands that are felled with partly limbed stands and stands without partly limbed assortments. The difference in performance is clear and shows that the partly limbed assortments strengthen the multiple tree handling harvesters positive effects in low dimension thinnings.

The main purpose of this study is to investigate the productivity effects of multiple tree handling in thinnings. Other important elements have been to investigate in which extent multi-tree handling is used in stands with different stem volumes and the impact of collecting partially delimbed fuelwood assortments has on harvesting performance. The study is based on data from thinnings in Sydved and contractors' operating activities. Collection and compilation of operating schedules, number of stems and surveyed volumes from several contractors and a large number of executed orders underlying the results. Multiple tree handling is used to a much greater extent at lower average stem volumes. Prediction models for productivity of the multiple-tree handling harvesters in the study differ from the productivity models for single-tree handling. In the model developed in this study productivity is not as dependent of stem volume as reference models.

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.

The aim of this study was to quantify the productivity and the costs of different harvesting systems (teams), containing harvesters equipped with accumulating harvester heads and forwarders, in first commercial thinnings were an integrated harvest of pulpwood and energy wood were performed. In the beginning the plan was to study and measure 20 sites before and after harvest. Due to storms during the summer of 2010, complete data could only be obtained from 8 of these 20 sites. Seven of these sites were privately owned and one was owned by UPM, all of the sites had been pre-commercially thinned. The mean stem density before harvest was 2578 stems per ha and the mean stem volume was 0.074 m3solid over bark.On average 1518 stems/ha was harvested.

Sitka spruce (Picea sitchensis) is a tree species that have its natural distribution along the West Coast of North America, from Alaska in the north to northern California in the south. Sitka spruce is a typical coastal tree species that can reach heights up to 85 meters and occurs in single pure as well as in mixed stands. The main purposes of this study were to describe the Sitka spruce growing characteristics and the volume production in comparison to spruce (Picea abies). The possibility to predict future volume production by using prognosis tools designed to be used on spruce were also studied. The material that has been used in this study are permanent sitka trials established by the Faculty of Forestry fixed Sitka trials and also material gathered in this study. A literature study was also carried out in order to determine the Sitka spruce growing characteristics. Sitka spruce has a high adaptation and a high volume production on a broad scale of soil types. The tree species is a pioneer species that has a fast early growth and in combination with sharp needles it is less susceptible to animal browsing than spruce. The factor that is the single most limiting factor for where the Sitka spruce can be planted is frost. This factor can be limited by using plant material with a well-suited provenance. According to the literature, the Sitka spruce has an average total volume production that is between 20-40% higher than spruce.

Prescribed burning was commonly used for site preparation in Sweden to establish new forests until the 1960?s, when mechanical scarification was introduced. During recent decades the interest in prescribed burnings has increased again, mainly due to certifications of forestry stating that 5% of the regeneration areas should be burned on dry and mesic soils. The objective of the study was to evaluate actual influence of prescribed burning compared to other site preparation on stand stem density, growth parameters and tree damages for Scots pine (Pinus sylvestris L.) after direct seeding and planting. The study also attempts to simulate growth until first thinning.

One of the most important components of a harvester is the crane. Most harvester cranes are only possible to pivot (or horizontally rotate) at the crane pillar. Cranab in Vindeln, Sweden, has developed a new type of harvester crane which has an extra pivot point on the outer boom. This makes it possible to reach around residual trees, easing thinning work in dense stands. The aim of the study was to analyze if the use of a pivoting outer boom (POB) crane gave an increase in thinning production and if there were any differences in time consumption between the work elements for the POB crane and a conventional crane. A Valmet 911.3 equipped with a POB crane was used in the study.

This study is done together with Sydved AB in the summer of 2012. The purpose of the study is to analyse how different quantity of assortments influence the production for forwarders and harvesters with multiple tree handling aggregate in thinning, by different tree volumes. To make this analyse a time study was performed where three entrepreneurs work has been analysed. Beside the analyse, of different quantity of assortments, has also been analysed how the tree volume and a forest fuel assortment effect the production. The result of this study shows that the quantities of assortments have a significant meaning for the production. The biggest differences are most distinct between one and three assortments in the smaller tree volumes where production goes down if the quantity of assortments increase.

The background to this study is that the forest company, Holmen, has found large discrepancies between harvested volume and the measured volume at the industry. Factors like bark features, breakage, double tops, bends and stem damages was noted, and all stems were measured manually. Hypothesis testing with the method "random in pairs" were used to examine whether the harvester measured values significantly differed from the manually measured. The result of a properly calibrated harvester shows in average underestimation of the volume with Skogforsk Pine as a bark function. This means that the harvester isn´t the reason why the volume measured in the industry is lower, the fault is elsewhere. The study also indicates a need for a unique bark function for logepole pine..

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.

The annual demands for forest fuels increases in Sweden. At present, large unutilized biomass resources is found in young, dense forests from which about five million oven-dry tonnes (ODt) (23 TWh) could annually be extracted as forest fuel. But harvesting small trees give high logging costs and new cost-efficient harvesting techniques are therefore required. The aim was to study the productivity of Vimek 608 BioCombi in forest fuel thinning of Lodgepole pine and to calculate the economy of the harvesting and estimate the thinning quality. The time study was performed in Åmarken in the county of Västerbotten.

This work was conducted during spring and summer 2012 together with the company Uppsala Academy of Management as the principal. The two main objectives for the work are that: ? Make a comparison between the measured volume in the standing forest and the measured volume at the industry on Uppsala Academy of Managements actual stumpage sale volume to see how well it conforms. ? Examine if the buyers see any particular advantages or disadvantages of actual stumpage sale volume and what they think of Uppsala Academy of Managements actual stumpage sale volume and structure in general. I chose to use actual stumpage sale volume from the tree years 2009, 2010 and 2011 in my work. I divided the actual stumpage sale volume following four categories which was pine, spruce, pine/spruce and seed trees. After that I picked out sixteen actual stumpage sale volumes from each category to be a part of the work.

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.