I Sverige finns ca 1,2 miljoner hektar skog som bedöms ha omedelbart röjningsbehov. Skog där röjningen uteblir eller är svag kan komma att klassas som konfliktbestånd. I konfliktbestånd är stammarna många och diameterspridningen stor och dessa kan då behövas underröjas innan gallring. I denna studie jämfördes produktionen, kostnaderna och intäkterna från fyra olika underröjningsbehandlingar, oröjd, siktröjt, röjt allt upp till 5 cm i brösthöjd och röjt allt upp till 7 cm i brösthöjd. Behandlingen oröjd gav det bästa nettot och sämst hade upp till 5 cm efter gallring och uttransport av virke.

The main purpose of this study is to investigate how to reduce the high, and every decade raising, pre-clearance cost. The pre-clearance is today carried out with a brush saw and paid per labour hour. All small trees not suitable for pulpwood are removed to simplify the later work of the harvester. The study compares the economic results from thinning of four parcels each treated differently regarding harsh or light pre-clearance and extraction of only pulpwood, or both pulpwood and fuel wood. In this type of spruce stand the study indicates that a lighter pre-clearance, followed up with both pulpwood and a fuel wood extraction, has a much better economy than the traditional method of hard pre-clearance and only pulpwood extraction..

By using the children's own thoughts and stories this theses aim to investigate and illustrate the phenomenon of rough and tumble play and its existence among five year olds in preschool.    The formulations of the questions are:What do children consider as rough and tumble play? - and what characterise that?From without a perspective of rough and tumble play, which kinds of rough and tumble play do the children play in preschool? - and how do those characterise?What makes rough and tumble play possible and accepted for the children to play in preschool?In this thesis I have investigated the questions above by interviewing 11 five years olds about how they consider rough and tumble play in preschool. From without Birgitta Knutsdotter Olofsson's and Torben Hangaard Rasmussen's view about play and rough and tumble play I created a perspective of rough and tumble play, which I used for analyzing the empirics. With rough and tumble play I mean games or plays that includes wrestling, hitting, kicking, pushing, chasing, running or/and the use of weapons against other human beings or other visualized beings or/and human beings.The conclusions are that children has many different opinions of what rough and tumble play is. Depends on who you are asking you will get a different perspective.

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.

This thesis presents the implementation of a knowledge base system for rough sets [Paw92]within the logic programming framework. The combination of rough set theory with logic programming is a novel approach. The presented implementation serves as a prototype system for the ideas presented in [VDM03a, VDM03b]. The system is available at "http://www.ida.liu.se/rkbs". The presented language for describing knowledge in the rough knowledge base caters for implicit definition of rough sets by combining different regions (e.g.

The purpose of this study is to compare the economic differences between withdraw of forest fuel and withdraw of pulpwood in first thinning, to see which method gives the maximum profitability (income - cost). Another purpose is to investigate the economic impact of the thicket cleaning. The study compares four different methods: i) pulpwood output with thicket cleaning, ii) pulpwood output without thicket cleaning, iii) forest fuel output with thicket cleaning and iv) forest fuel output without thicket cleaning. The study was conducted in a 30-years old stand, dominated by spruce, outside Harg in Uppland. The method that generated the best economic net income was pulpwood without thicket cleaning. It generated a positive net of 1,383 SEK per hectare. Forest fuel output without thicket cleaning also generated a positive net in 720 kronor per hectare.

The demand for renewable energy is increasing in Sweden. This consequently increases the pressure for and willingness to pay for forest fuels. One method to extract forest fuel from suitable commercial thinnings is the "long top method? (LT-method). With this method saw logs and non-delimbed tops are recovered, i.e.

The bioenergy market has been introduced relatively late in a perspective of the Swedish forestry. Nowadays branches and tops are used more frequently as bioenergy after harvesting. Therefore, it has developed a competitive situation between pulpwood and bioenergy. This situation has even established some questions. Two examples of these are: ? At what top diameter should the final piece of pulpwood be crosscut to get the best economically result? ? Should the top diameter, at the final piece of pulpwood, be crosscut at a thicker or smaller diameter than what is done today? The purpose of this report is to answer these two questions when the harvesting is made motor manually in beech stands.

The purpose of this study was to estimate the removal of biomass in connection with thinning operations in young stands that are dominated by small diameter trees. The economy of such operations depends on the products generated as well as the performance of the harvesting systems. Conversion tables designed to predict the outcome based on harvesting method was another goal of this study. Removal of biomass affects the nutrient composition of the site. Therefore it is a purpose that this study will provide researchers with some variables that can be utilized when studying this aspect. Trees were harvested and divided into bunches based on diameter.

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.

Stands where pre commercial thinning has been ignored or inadequate often tend to have high stem density and low average diameter when they reach heights of thinning. In such stands, it can often be expensive to do a conventional pulpwood harvest as a first thinning. This study investigates the development of the stands and the economic outcome of forest fuel extraction, or a combined harvest as alternatives to the ordinary pulpwood harvest. Simulations in Heureka StandWise were performed for two thin and dense stands, which were constructed by data from the Swedish National Forest Inventory. The simulations show that the extraction of forest fuel in first thinning at an early stage can provide higher net revenue compared to conventional pulpwood harvest at the same time or later.

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.

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.

Holmen Skog AB is an important supplier of conifer pulpwood to the Iggesund Paperboard mill. After logging and transport to the landing by a forwarder, the wood is loaded on trucks for further transport, often by using separate loaders. During this handling process considerable amounts of stone material is sometimes mixed into the pulpwood and this causes problems for the industry. The aim of this study is to identify which part of the chain from forest to pulpmill, that contributes the most to this contamination. Sizes and total volumes of the contaminating stones were also investigated.

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.