Stump harvest could be found in the late 1970?s and the early 1980?s. And now when the prices on energy are high it has become an interesting topic again. This work has been conducted within Holmen Skog?s stump harvest testing in Norrköping.

Stump biomass is energy rich and Stump harvesting for use as fuel become more and more interesting in Sweden. Swedish Forest Agency (2009) has estimated that Stump harvesting in Sweden would respond to an annual energy supply of 57 TWh/year. However, stump has not been recognized as a bioenergy resource in Sweden. Suitable methods for pre-treatment of stump are probably of great importance to make it accepted as fuel. It is therefore rewarding to carry out an investigation in this area for stump. This report represents results from a diploma project, which was aimed to develop a fixed bed reactor for experimental study of biomass torrefaction, followed by TG analysis and kinetic modelling employing Ozawa method and different kinetic models including one-step and three-pseudo-component models.

The Swedish parliament has decided that Sweden should increase its usage of renewable fuel sources to a level of 50% of the total energy consumption in Sweden by the year 2020. One way to reach that goal may be to increase the usage of stumps as a bio-fuel. In Sweden Stump harvesting is possible on about 5-10% of the total harvested area and thus contribute with 1,3 - 2,6 TWh per year. An increase stump harvest doesn't come without its drawbacks for the environment. When harvesting stumps a tracked excavator is used to pry the stumps from the ground and then cut the stumps into smaller pieces.

Stump wood was used between 1850 and 1950 for production of tar and as firewood. In the 1950s the use decreased because of the introduction of the cheap fossil oil. In the 1970s stump wood became an interesting issue again as a raw material for the pulp industry. Stump lifting has today become a possible source for bioenergy. The objectives with this study were to investigate the productivity of stump lifting and stump extraction, and to analyse the economy.

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.

Stump wood is a hot alternative when the heating plants demands more and more forest fuel. The aim with the study has bean to calculate the costs in four different systems for transportations of stump wood, examine if there are any differences in fuel quality for the stump wood in the different systems, analyse if the fuel quality in stump wood is affected with the time it lays by the road side and how much space the stump wood demands on the road side. To calculate the costs for the different systems a system analysis was carried out, where some of the costs were collected through field studies on Holmen Skog stump experiment and other costs were collected from literature and contacts. Data for the fuel quality study was collected from Eons heat plant in Norrköping. Data for the study of how much space stump wood takes along a roadside was collected from field studies.

Stump treatment today requires large quantities of clean water mixed with the protective product Rotstop, to fully cover the stump surface. In order to reduce the water consumption without reducing the coverage of the stump surface, the pressure in the stump treatment device can be increased. Therefore, the Phlebiopsis gigantea (Fr.) Jül. suspension used as a biological control agent to prevent Heterobasidion annosum (Fr.) Bref. infection was pressure-tested.

In order to reduce greenhouse gas emissions from human activities fossil fuels will have to be replaced with renewable energy alternatives, such as bioenergy. Sweden has a great potential to produce bioenergy derived from forest products and there is currently a great interest within Sweden in using stumps for bioenergy production. However, the environmental consequences of the method need to be investigated before stump removal can be performed on a large scale. Swedish forest soils contain large carbon pools and a different land use may change conditions so that soils that presently act as sinks of carbon could potentially turn into sources of carbon release instead. This study investigates the initial effects of Stump harvesting on the emissions of three greenhouse gases, carbon dioxide, methane and nitrous oxide. The emissions were measured from the soil surface in a Norway spruce forest located in the southern part of Sweden.

Dead wood is important for many species. The amount of coarse dead wood (diameter >10 cm) is much lower in managed forest than in unmanaged forests. Stumps constitute the largest proportion of the volume of coarse dead wood in managed forests. Since stump harvest for biofuel may increase, the amount of dead wood will decrease even more, which may threaten biodiversity. The first aim of this study was to compare the amounts of fine woody debris (FWD, .

The objectives of this research were to determine whether the natural rattan resources in Sulawesi, Indonesia can cope with the strongly increased harvesting pressure that has occurred over the last centuries. I was furthermore looking for patterns in the rattan population dynamics that might give a hint on how the harvesting system could be improved to ensure a maximum sustainable yield. To answer these questions, I developed an individual-based model to analyse the dynamics of rattan growth in connection with rattan harvests by locals to identify sustainable levels of rattan harvests around villages in Sulawesi, Indonesia. Scenarios with different harvesting intensities were run to compare the change in harvest amount. For a given harvesting pressure, scenarios with a high number of harvesters and a low harvesting frequency had the same effect as scenarios with high harvesting frequencies and a low number of harvesters.

The purpose of this report was to investigate if there are any correlation between spruce medium height in young spruce stands and the number of birch stump shoots. The purpose was also to investigate if there are any correlation between the spruce height growth after clearing and the mean height of birch stump shoots. The reason for this investigation is that the problem with birch stump shoots after clearing can be expensive if there must be additional clearings before the first thinning. The study provides no apparent association and therefore no special clearance height is recommended. In the final stages of the work there are given some comments on the study´s weaknesses. Finally topics for further research are suggested..

Dead wood is important for many species. The amount of coarse dead wood (diameter >10 cm) is much lower in managed forest than in unmanaged forests. Stumps constitute the largest proportion of the volume of coarse dead wood in managed forests. Since stump harvest for biofuel may increase, the amount of dead wood will decrease even more, which may threaten biodiversity. The first aim of this study was to compare the amounts of fine woody debris (FWD, .

In the near future we need to reduce the greenhouse gas emissions significantly for the benefit of the environment around us. The European Union has de-manded a variety of climate and energy goals to be achieved by year 2020, the ?20-20-20? targets. With these aims, The European Union means that we must reduce our emissions from fossil fuels and instead increase our renewable fuels. With stump harvest in the forest it?s possible to increase the use of renewable fuels and reduce our emissions from fossil fuels.

Dead wood is important for many species. The amount of coarse dead wood (diameter >10 cm) is much lower in managed forest than in unmanaged forests. Stumps constitute the largest proportion of the volume of coarse dead wood in managed forests. Since stump harvest for biofuel may increase, the amount of dead wood will decrease even more, which may threaten biodiversity. The first aim of this study was to compare the amounts of fine woody debris (FWD, .

Each year, Heterobasidion spp. is a major cause of economic losses to forestry in the northernhemisphere, including Sweden. New results indicate that pre?commercial thinnings could be at riskfor Heterobasidion spp. infections.