Browsing by Subject "tehotuntituottavuus"

Sort by: Order: Results:

Now showing items 1-3 of 3
  • Muhonen, Olli (Helsingfors universitet, 2012)
    Forest energy harvesting has increased significantly in recent years. The extraction of forest energy is usually done with conventional forwarders. The productivity of extraction work is, however, quite poor due to a low material density, which results in a small load size. The objective of the study was to increase the productivity of forest energy extraction via solutions that increase the load size. The first method that was studied involved widening the load space hydraulically. The other solution was based on compressing the load with hydraulically tiltable stakes. The study was conducted as a development study. The field studies were carried out in the summer and autumn of 2011 on harvesting sites managed by Metsähallitus and Metsäliitto in the Jyväskylä region. The study material comprises a total of 139 loads. There was a significant difference in raw density between the logging residues and stump pieces for the widening and compressing load space solutions. For this reason, it does not make sense to compare the two load space solutions to each other. The analyses were based on the reported load scale tonnes. Both load space alternatives increased the load size by 20-30 per cent depending on the assortment. For logging residues, the increase in efficient hour productivity for extraction was 13 per cent and for stump pieces it was 30 per cent. With the compressing load space, the efficient hour productivity for full trees increased by 17 per cent. For logging residues, the increase was 5 per cent and for stump pieces it was 12 per cent. Compression was not a successful method for stump pieces and even for logging residues the benefits were mainly based on the increased load space. Compressing the load is mainly beneficial when extracting full trees. The project was carried out together with Osuuskunta Metsäliitto (now Metsä Group), Metsä-Multia Oy and Ponsse Oyj. The modelling work was done by Metsäteho Oy. This study shows results of Metsähallitus project “Maastokuljetuksen kehittäminen”. The project is part of the EffFibre (Value through Intensive and Efficient Fibre Supply) research and development programme coordinated by Forestcluster Ltd.
  • Karjalainen, Reima (Helsingin yliopisto, 2019)
    Wood reserves and growth in Finland’s forests are greater than ever. The 12th National Forest Inventory (NFI12) 2014–2017 measured the volume of trees at 2.5 billion cubic meters and the annual growth rate at 107 million cubic meters. The results showed that forest regeneration was well managed, but there was room for improvement in the care of seedlings and young stands. The late tending of seedling stands increased about 11% compared to the previous NFI11 inventory in 2009–2013. Costs of tending seedling stands and for first thinning in young stands are high. Harvesting costs for thinning from below methods including forest haulage constitute over half of all expenses. Reducing forest management costs is one of the most important goals in Finnish forestry. Using a boom-corridor thinning method would improve the cost-effectiveness of harvesting timber and wood bioenergy. The purpose of this study was to examine the time required for boom-corridor thinning methods and productivity of the mechanical first thinning in young pine forests in the existing harvesting technologies and well as to compare the productivity and costs of harvesting to the traditional practice of thinning from below. The study was performed for a project of the Natural Resources Institute Finland (LUKE) that studied boom-corridor thinning as a harvesting method for the first mechanical thinning of young Scots pines. The boom-corridor thinning development project was implemented in 2017–2018 as part of the rural development plans for North Karelia, Central Finland, and Northern Finland in 2014–2020. The objective was to sustainably manage forest resources and support renewable energy production. Study was made of Konnevesi test stands’ time study material and the tree database. The study compared the time required by three thinning methods: boom-corridor thinning in which the corridor location was tagged beforehand, boom-corridor thinning in which the operator selected the corridor location, and traditional thinning from below. A Ponsse Beaver harvester equipped with a Ponsse H6 harvester head was used in the Konnevesi test stands to thin by single tree harvesting. Time study and comparative research shows that boom-corridor thinning was more productive and economical than traditional thinning from below. For boom-corridor thinning method M2, in which the location of a corridor was tagged, the productivity E₀ was 18% higher than the traditional thinning from below method, when the average density of the removed trees were18 % bigger than harvesting from below. For boom-corridor thinning method M3, in which the operator chose the location of a corridor, the productivity E₀ was 4,5% lower than the traditional thinning from below method, when the average density of the removed trees was 26% lower than the other thinning methods. For boom-corridor thinning methods M2 and M3, productivity E₀ was 6,7% higher than the traditional thinning from below method. The statistical analysis shows that the differences between the harvesting methods correlate with the stem size, which was bigger in the boom-corridor thinning methods than the thinning from below, especially in the treatment M2.The boom-corridor thinning method M2 unit costs €/m³ were 15% lower than those of the traditional thinning from below method. For boom-corridor thinning method M3, joint average unit costs €/m³ were 5% higher than those of traditional thinning from below method M1 and 20 % higher than boom-corridor thinning method M2. The study concluded that boom-corridor thinning is a productive harvesting method worth developing for the first thinning of young forests. Using boom-corridor thinning methods will reduce costs of first thinning forests significantly. Compared to previous research, the main results of this study were similar, with a 16% increase in productivity. Other studies suggest productivity could be doubled with technology developed for boom-corridor thinning.
  • Hämäläinen, Juuso (Helsingfors universitet, 2014)
    The newly reformed Forest Law in 2014 is going to expand the usage possibilities of uneven-aged forest management as it is no longer concerned to be a part of ”for special sites only” forest management. Nowadays, the number of forest owners, who are aiming towards multiattribute forest management, is increasing and uneven-aged forest management is probably going to increase its proportion. But there is a major problem of utilizing uneven-aged forest management, as there are basically neither significant practical models nor knowledge from the operational point of view. This research was completed as a part of Finnish Forest Research Institute’s research program in co-operation with Metsä Group Ltd. and Forest-Linna Ltd in Central Finland. The goals of the research were to analyze; the time-consumption of selection cutting and factors affecting it, the quality and quantity of the forest stand after cutting from the forest structure’s and tree damages’ point of view, and to research the need and possibilities of training for harvester operators. The effective time-consumption between Scots Pine and Norway Spruce didn’t statistically differ neither in clear cutting nor selection cutting, so a group of conifers was created for the comparison between them. The effective time-consumption was 15 – 17 % higher and the effective productivity 12 – 14 % lower in selection cutting, when the average stem volume was fixed between 0,700 m³ and 0,897 m³ in both methods. Processing of the stems located on the strip road was faster than those located on the sides. Out of the undergrowth saplings (h<2,5 m), which had growth-potential for future, 4,7% were injured and 42,5% destroyed or disappeared. The major factors causing either injury or destruction were slash and logs. Out of the remaining trees (h>2,5 m) 19,3% were injured, when all the recorded injuries were taken into account. According to the Finnish Forest Regulation, 7,7% of the remaining trees (dbh>7,0 cm) were injured. A prototype basal area chart was used for allowing the harvester operator to picture the remaining basal area at a single working location. The chart consisted of the basal area of different diameter classes at a half-circular location restricted by an 11-metre boom. The chart was designed for this research by Pentti Niemistö. By using the chart; oral information and a practice area, where trees were selected beforehand, the harvester operator was able to achieve different given basal area goals by fair means on the other parts of the research stumpage.