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The study evaluates the development of national supply security. The aim of the paper was to examine the supply security of solid domestic fuels for Finnish combined heat and power plants (CHP) in a domestic fuel disruption. The consumption of wood fuels has increased in recent decades and discussion of supply security has become important nationally. On the other hand, the consumption of peat and coal has been replaced by biomass, which has created questions over its sustainable availability regionally and nationally. The study utilised a questionnaire targeting major combined heat and power plants utilising domestic fuels located around Finland. The response rate of questionnaire was as high as 88%, which reflected the importance attached to the subject. The most significant concern was that economical operating conditions for peat should be ensured, or wood fuels will face difficulties in securing the energy supply by itself. However, the CHP plants were prepared to increase the use of wood fuels, for example by developing logistical systems, investing in fuel terminals and intensifying cooperation with fuel suppliers. Topic of the study is also important internationally. [ABSTRACT FROM AUTHOR]

Increased use of forest biomass for energy and rising transportation costs are forcing biomass suppliers towards better moisture content management in the supply chain. Natural drying is used to decrease moisture content of energy wood. Drying is dependent on wood characteristics and weather conditions. Weather-dependent drying models for estimating the optimal storage time based on average moisture changes in fuel wood stacks stored outdoors have been developed for different stem wood and logging residues. Models are an easy option for estimating the moisture content of energy wood piles compared to sampling and measuring the moisture of samples. In this study, stand and roadside storage models for logging residues were validated against data from field studies and forest companies. Over 200 reference piles for the stand model, 23 piles for the roadside model and 10 piles for the combined model were studied. Results of the validation are promising. The difference between measured and modelled moisture was on average only 0.35%. The presented models can be implemented anywhere in Finland, because the Finnish Meteorological Institute has a weather observation service offering weather history data for every location in Finland. For international use, parameters need to be estimated on a case by case basis, but it should be possible to implement the approach also elsewhere. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to determine the amount of boron in three Norway spruce (Picea abies (L.) Karst) stands in eastern Finland, where boron deficiency is common. A further aim was to estimate the effects of logging-residue harvest on boron balance and the boron-to-nitrogen ratio on these sites. The data were obtained from a 30-year-old and a 62-year-old healthy spruce stand as well as from a 35-year-old spruce stand with boron deficiency and growth disorders. Altogether 2.1 and 2.4kgha−1 boron, respectively, were bound in trees+organic layer+0–10cm mineral soil layer in the two healthy stands, and 0.9kgha−1 in the boron deficient stand. For the amount of boron in the healthy stands the trees made up 43% and 49%, respectively, and in the boron deficient stand 38%. Stems contained 30% and 40%, respectively, of the boron in trees in the healthy stands and 37% in the boron-deficient stand. Only 11–13% of the tree boron was in the needles. The amount of nitrogen bound in the ecosystem studied was 2.1 and 2.5Mgha−1, respectively, in the two healthy stands and 3.0Mgha−1 in the boron deficient stand. In the ecosystem the trees contained 21–29% of the amount of nitrogen. Stems contained 14–24%, respectively, and needles 26–36%, respectively, of the nitrogen in the trees on the studied stands. In stem-only harvestings, relatively more boron than nitrogen would be removed from a site. In the boron-deficient stand, boron fertilisation for 3years nearly doubled the amount of boron in the ecosystem. Only 38% of the fertiliser boron (2kgha−1) was found in the ecosystem components studied. [Copyright &y& Elsevier]

Abstract: The effects of whole-tree thinning on soil were investigated in 9 Scots pine and 4 Norway spruce experiments in Finland. Three pine experiments had been thinned once, the other experiments twice. Time between thinning and soil sampling varied from 3 to 30years. Amounts of exchangeable base cations, Ca, K and Mg, seemed to have decreased after whole-tree thinning. The larger the amount of removed logging residues, the greater these decreases tended to be. Changes in base cations in soil due to whole-tree harvest were more expected than were changes in the amounts of nitrogen, because, e.g. potassium and magnesium in logging residues of one thinning corresponded, on average, to 60–70% and to 30–40%, respectively, of the total amounts of nutrients in the organic layer, but nitrogen only to 10%. Overall, in the experiments studied, whole-tree harvest induced only slight changes in soil nutrients. The changes would be even smaller if the present motorised whole-tree harvest, in which logging residues are not totally removed, were compared to the present motorised stem-only harvest, in which logging residues are not distributed evenly over the cutting area. [Copyright &y& Elsevier]

Abstract: Energy wood harvesting in young forests presents an economical challenge and has been dependent on subsidies in Finland. Whole-tree harvesting systems have proved to be most productive when carrying out energy wood harvesting in cleanings and early thinnings in young forests. The application of integrated energy wood and pulpwood harvesting is less common. It was hypothesized that multi-tree harvesting (MTH) with the OM-Waratah 745 single grip harvester head could change harvesting logistics and improve productivity for integrated energy wood and pulpwood thinnings. Two variations of MTH were compared with single-tree harvesting (STH). The logging methods studied were: (1) conventional single-tree harvesting with pulpwood and energy wood processed at the strip road; (2) multi-tree harvesting with pulpwood and energy wood processing along the strip road (MTH1); and (3) multi-tree harvesting at the stump where the aim was to leave the logging residues distributed evenly over the harvesting area and not on the strip roads (MTH2). MTH methods were 28–35% more productive than the single-tree harvesting. The biggest differences in work stages were found in the felling and delimbing stages. In single-tree harvesting felling was 9–26% and delimbing 14–27% slower than in multi-tree harvesting. MTH2 distributed 13% of residues further than 7 m from the strip road center. With STH and MTH1 only a good 1.2–1.7% was placed this far, and 74.4 and 62.0% respectively within 3 m. [Copyright &y& Elsevier]

Abstract: The number of slash bundlers and the volume of slash bundling have been rapidly increasing during the last few years in Finland. However, no comprehensive time or follow-up studies have been carried out on slash bundling technology in Finland or in any other country. Metsäteho Oy carried out studies on the productivity and costs of slash bundling in different Nordic recovering conditions. The study methods included both time and follow-up studies. Data were collected during the summer and winter period primarily in Norway spruce (Picea abies L. Karst.) dominated clear cutting sites. The bundling techniques performed by different types of bundler (Fiberpac 370, Timberjack 1490D, Pika RS 2000, Valmet WoodPac) were studied. The average productivity of slash bundling was 18.1 bundles per operating (E 15, including delays shorter than 15min) hour with the Timberjack 1490D and Fiberpac 370 bundlers in the follow-up study. The operator of the slash bundler had the greatest effect on the productivity of bundling. The prerequisite for increased bundling volumes is a reduction in the costs of the most expensive sub-stage of the bundling supply chain, i.e. bundling itself. This requires improved recovery conditions at bundling sites, increased bundling productivity, larger sized bundles, and the execution of bundling operations in two work shifts using an efficient bundler and effective operator working methods. Implementation of these development measures will bring the bundling supply chain up to a speed that makes it the most competitive supply chain for forest chips in terms of total supply costs for long-distance transportation distances of more than 60km. [Copyright &y& Elsevier]

Abstract: Renewable energy sources play an important role in the Finnish energy and climate strategies which are implemented partly through the Action Plan for Renewable Energy Sources. Enhancement of wood energy plays a key role in the plan. A special emphasis is given to forest chips produced from small-sized trees from early thinnings and above-ground and below-ground residual biomass from regeneration cuttings. The production goal of forest chips is 5 millionm3 solid (10TWh) in 2010. The use of forest chips is promoted by means of environmental taxes, financial aid for investments, and financial support for research, development and commercialization of technology. In 2002, altogether 365 heating and power plants larger than 0.4MW used forest chips. The total consumption was 1.7 millionm3, the use of small houses and farms included. The growth of use is presently about 350000m3 per annum, but reaching the official goal will require an annual growth of 400000m3 during this decade. The consumption of roundwood per capita, 15m3 per annum, is in Finland 20 times as high as the average consumption of the EU countries, respectively. Consequently, residual forest biomass is abundantly available. The capacity of heating and power plants to use forest chips is large enough to meet the goal. However, users require competitive chip prices, good quality control of fuel and reliable supply chains, and new efficient procurement systems are being developed. The paper deals with the drivers of this development: support measures of the Government; strong support to research, development and commercialization of forest chip production from the National Technology Agency Tekes; advanced infrastructure for the procurement of timber for the forest industries; positive attitude and active participation of the forest industries; the active role of leading forest machine and boiler manufacturers, and the possibility to cofire wood and peat fuels in large fluidized bed boilers so as to secure the availability of fuel in all conditions, stabilize the moisture content of fuel and reduce the emissions from combustion. [Copyright &y& Elsevier]

Abstract: In recent years the transportation of uncomminuted energy wood raw materials has been on the increase in Finland. As a result of the low bulk density of unprocessed raw material, the size of the load is usually limited by volume rather than mass capacity. In this study, the profitability of transporting uncomminuted raw materials is evaluated. A follow-up study was done to gather time consumption and load size data. In this study, we piloted a monitoring system installed in computers of trucks combined with GPS. In the beginning of the year 2004, the average load size of loose residues was 52MWh and the moisture content 47%, with stumps 67MWh (37%), with bundles 73MWh (50%) and with forest chips 85MWh (46%). The average total weight of loads was kept under the maximum weight limit, 60 tonnes, for all uncomminuted raw material types. There was some 10 tonnes of potential load capacity left. The most likely improvements in the transportation of the loose raw materials will involve increasing the load size and decreasing of the terminal times. Especially the truck–trailer combinations with extended trailers are becoming more common in Finland. [Copyright &y& Elsevier]

Abstract: Renewable energy sources have been identified to play an important role in mitigating climate change. The main reason is that carbon dioxide emission is avoided when fossil fuels are replaced. This paper presents a study focusing on direct and indirect greenhouse gas emissions from fuel chip production in Finland. The fuel chips studied were produced from logging residue at final harvest. Five different fuel production chains were considered. The calculations showed that fuel chip production from the residues of final harvest is very efficient from the viewpoint of energy use during collection, chipping and transportation. Only an input of 2–3% of the produced energy is needed, which means that roughly 30 to 50 units of bioenergy is produced for every unit of (fossil) energy consumed. The emissions from collecting, chipping and transporting the residues were evaluated to be about 4–7kg depending on harvesting and chipping methods and transportation distance. Emissions of greenhouse gases (other than ) from burning forest residues in a modern CHP-plant were evaluated to be small, about 2kg . If nitrogen losses are compensated for with fertilisation, the additional greenhouse gas emissions were calculated to be about . The calculations showed that in a favourable situation as much as 97–98% of the greenhouse gas emissions could be avoided by substituting a fossil fuel with wood fuel, but even in an unfavourable situation the amount avoided should be higher than 75%. [Copyright &y& Elsevier]

Abstract: Finland has large forest fuel resources. However, the use of forest fuels for energy production has been low, except for small-scale use in heating. According to national action plans and programs related to promotion of biofuels, the utilization of such resources will be multiplied over the next few years. The most significant part of this growth will be based on the utilization of forest fuels, produced from logging residues of regeneration fellings, in industrial and municipal power and heating plants. Availability of logging residues was analyzed by means of resource and demand approach in order to identify the most suitable regions with focus on increasing the forest fuel usage. The analysis included availability comparisons between power plant sites and resource allocation in a least-cost manner according to supply cost, and between a predefined power plant structure under given demand and supply constraints. Spatial analysis of worksite factors and regional geographies was carried out using the Graphics Information System-model (GIS-model) environment via geoprocessing and cartographic modeling tools. According to the site-specific analysis, the supply potential of different locations can differ multifold. However, due to technical and economical reasons of the fuel supply and dense power plant infrastructure, the supply potential is limited to plant level. Therefore, the potential and supply–cost calculations depend on site-specific matters, where regional characteristics of resources and infrastructure should be taken into consideration, e.g., by using a GIS-modeling approach constructed in this study. [Copyright &y& Elsevier]

Abstract: The integration of logging residue extraction, along with the establishment of a new stand and soil preparation is a new idea. A dual-purpose machine has been developed in Finland. It can be used as both a scarifier and a slash forwarder without the need for time-consuming conversion work. According to research results, the machine has proved to be rather competitive. In average conditions, the integration decreases the cost of scarification and residue recovery by about 10%, when compared to separate operations with two machines. Slash forwarder–scarifier is ideally suited for use in small regeneration areas, where the costs of moving two separate machines between sites would constitute a large share of the total costs. By the slash forwarder–scarifier operators exposure to the whole body vibration during the work decreases due to slower driving speed, the machine''s greater weight and the position of scarifying plates in the middle of the machine body. [Copyright &y& Elsevier]

• Dynamics of N cycling was studied under spruce logging residues on a clear cut. • Stimulated N cycling processes increased N losses via leaching and N 2 O production. • Amount of residues affected soil N cycling and losses. This study aimed to determine the effects of Norway spruce logging residues on the early-stage dynamics of N cycling processes on a clear cut and how this is related to N losses via leaching or nitrous oxide emissions. We compared N cycling processes in soil under spruce logging residues (fresh residues 40 kg m−2) and in corresponding soil without the residues for four growing seasons on a clear-cut in southern Finland. In addition, two other sites were studied in the same region six years after clear-cutting in plots with three different amounts of spruce logging residues (0, 10, 40 kg m−2). Logging residues strongly stimulated net nitrification within the first three months after the residue treatment, and this stimulation continued over the whole study period, although NO 3 -N concentrations in the soil decreased. Residues increased the pH, rate of net N mineralization and microbial C-to-N ratio. N 2 O production in the laboratory and fluxes in the field were both studied after four growing seasons. N 2 O production was higher in the humus layer under the residues and originated from both autotrophic nitrification and denitrification. N 2 O fluxes in the field were low but were also higher in the residue-containing plots. N concentrations in percolate water were monitored for four years at the same site. Logging residues increased NO 3 -N and NH 4 -N concentrations; the highest concentrations were found during the second and third years after clear-cutting. After that the concentrations of dissolved organic N increased. Both the percolate water study at this site and the N cycling studies at the two other sites six years after clear-cutting showed that the largest amount of residues resulted in the highest rates of net N mineralization and net nitrification and the highest concentrations of mineral N forms in the percolate water. The amount and decomposition stage of the logging residues as well as the development of ground vegetation may together determine the dynamics of soil N cycling processes and losses. [ABSTRACT FROM AUTHOR]