Weight and volume of small-sized whole trees at different phases of the supply chain

Laurila, Jussi; Lauhanen, Risto

doi:10.1080/02827581.2011.629621

Cited by 11 publications

(12 citation statements)

References 7 publications

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“…Correspondingly, tree species-specific net calorific values of dry matter (MJ kg -1 ) were used according to Nurmi (1993). Moisture contents of 20%, 30% and 40% were used for artificially dried stem wood chips and a moisture content of 40% (Table 2) for delimbed stems stored at roadside landings (Hakkila 1989;Nurmi and Hillebrand 2007;Laurila and Lauhanen 2012;Nuutinen et al 2014). The dry matter loss of delimbed stems during nine months of storage was set to be 6.75% (Mäkelä et al 2000).…”

Section: Harvesting Conditions and Estimation Of The Potential Supplymentioning

confidence: 99%

“…Demand for fuel chips is often diachronic and shortages are usually buffered by means of stored material (Jirjis 1995;Rauch 2010;Filbakk et al 2011;Laurila and Lauhanen 2012;Laurila 2013;Rauch 2013;Eriksson et al 2014;Nurmi 2014). During the cold season of the year, the comminuting machinery and transportation equipment are in intensive use, while during the summer months, the problem is a lack of work (Laitila et al 2010b).…”

Section: Introductionmentioning

confidence: 99%

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Pre-feasibility study of supply systems based on artificial drying of delimbed stem forest chips

Laitila¹,

Ahtikoski²,

Repola³

et al. 2017

Silva Fenn.

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Highlights• With artificial drying and quick delivery, avoiding dry material losses of harvested timber, it could be possible to reduce the current costs of the prevailing procurement system based on natural drying of stored timber at roadside landings.• The maximum cost for the prospective drying process of fresh chips corresponds to, e.g., organization costs or stumpage price of delimbed stems. AbstractThis study was aimed at determining the maximum cost level of artificial drying required for cost-efficient operation. This was done using a system analysis approach, in which the harvesting potential and procurement cost of alternative fuel chip production systems were compared at the stand and regional level. The accumulation and procurement cost of chipped delimbed stems from young forests were estimated within a 100 km transport distance from a hypothetical end use facility located in northern Finland. Logging and transportation costs, stumpage prices, tied up capital, dry matter losses and moisture content of harvested timber were considered in the study. Moisture content of artificially dried fuel chips made of fresh timber (55%) was set to 20%, 30% and 40% in the comparisons. Moisture content of fuel chips based on natural drying during storing was 40%. Transporting costs were calculated according to new higher permissible dimensions and weight limits for truck-trailers. The procurement cost calculations indicated that with artificial drying and by avoiding dry material losses of timber, it could be possible to reduce current costs of the prevailing procurement system based on natural drying of timber at roadside landings. The maximum cost level of artificial drying ranged between 1.2-3.2 € MWh -1 depending on the supply chain, moisture content and procurement volume of fuel chips. This cost margin corresponds to, e.g., organization, forwarding and transportation costs or stumpage price of delimbed stems.

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Section: Harvesting Conditions and Estimation Of The Potential Supplymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pre-feasibility study of supply systems based on artificial drying of delimbed stem forest chips

Laitila¹,

Ahtikoski²,

Repola³

et al. 2017

Silva Fenn.

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show abstract

“…Studies on the quality management and profitability of energy wood procurement have been carried out (e.g. Hakkila 1962;Nurmi 2000;Laurila & Lauhanen 2012). Recently, the effect of girdling on the moisture content of small-sized trees for energy wood utilization has been discussed.…”

Section: Introductionmentioning

confidence: 98%

“…The survey of Hillebrand and Nurmi (2004) showed that the moisture content of small-sized whole trees at a good roadside storage site was about 40% after one summer. According to Laurila and Lauhanen (2012) the average moisture content of small-sized whole trees measured at the heating plant was about 43% after a roadside storage period of one year.…”

Section: Introductionmentioning

confidence: 99%

The effect of girdling on the moisture content of small-sized trees

Laurila¹,

Lauhanen

Hakonen

2014

Scandinavian Journal of Forest Research

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In this study, the effect of girdling on the moisture content of small-sized trees for heat energy production was clarified. The moisture content was measured for Scots pine (Pinus sylvestris), Norway spruce (Picea abies), and Downy birch (Betula pubescens) during two growing seasons after girdling. The trees were girdled at breast height for around 30 cm by removing the bark, phloem, and cambium from around the stem. At the beginning of the growing season the mean moisture content of the living Scots pine (P. sylvestris) and Norway spruce (P. abies) was 60%, and for Downy birch (B. pubescens) it was 50%. During the first growing season the effect of girdling on the moisture content was low, but during the second growing season the moisture content decreased significantly. The moisture content of the Norway spruce (P. abies) (23%) and Downy birch (B. pubescens) (33%) was at its lowest point at 14 months after girdling. There were no significant changes in the moisture content of the Scots pine (P. sylvestris) in this study. The results of this study can be used in basic research and in the development of energy wood production.

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“…Correspondingly, tree species-specific net calorific values of dry matter (MJ kg -1 ) were used according to Nurmi (1993) for stem wood, and for conifer stumps values from Hakkila (1978) were used. Moisture content of 31% was used for stumps (Laurila and Lauhanen 2010) and moisture content of 40% for delimbed stems (Hakkila 1989;Nurmi and Hillebrand 2007;Laurila and Lauhanen 2012;Laitila 2008;Nuutinen et al 2014). Moisture content was held constant within each system during availability and procurement cost calculations.…”

Section: Fuel-property Parametersmentioning

confidence: 99%

The cost competitiveness of conifer stumps in the procurement of forest chips for fuel in Southern and Northern Finland

Laitila¹,

Ranta²,

Asikainen³

et al. 2015

Silva Fenn.

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• Pre-grinding and integrated screening is a way of guaranteeing fuel quality, but, when the stumps' ash content is six per cent or below, the procurement costs are higher than with grinding of stumps at the plant. Because of high transportation costs, stump harvesting is the most profitable in Southern Finland, where there is greater availability of stumps than in Northern Finland. AbstractThe aim of this study was to evaluate cost competitiveness, at regional level, of various systems for stump transportation and grinding, and to compare the results to the procurement costs of delimbed stems from early thinnings at the stand and regional level. The accumulation and procurement costs of stumps and delimbed stems were estimated within a 100-kilometer radius from two power plants located in Kouvola and in Kajaani. The analyses were performed as simulated treatments in clear cuts and thinnings of young stands, using existing productivity and cost functions, alternative ash percentages for stump wood, and yield calculations based on the forest industry regeneration felling stand data and the sample plots data of the National Forest Inventory of Finland. The results were expressed as Euros per solid cubic meter (€ m -3 ) and Euros per megawatt hour (€ MWh -1 ).The results highlight the need to improve stump fuel quality and increase the heating value. The procurement cost of stumps was about 1 € MWh -1 lower in Kouvola compared to Kajaani, when using conceivable ash content of 6% for stumps ground at the plant, and ash content of 1.5% for stumps pre-ground at the roadside landing. The procurement costs of stumps were, on average, 0.55 € MWh -1 lower compared to delimbed stems in Kouvola, and on average 0.6 € MWh -1 higher in Kajaani. Pre-grinding and integrated screening is a feasible way to guarantee the fuel quality expressed as ash content already at roadside landings, but the procurement costs are higher compared to grinding stumps at the plant, when the ash content of ground stumps is 6% or less.

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Weight and volume of small-sized whole trees at different phases of the supply chain

Cited by 11 publications

References 7 publications

Pre-feasibility study of supply systems based on artificial drying of delimbed stem forest chips

Pre-feasibility study of supply systems based on artificial drying of delimbed stem forest chips

The effect of girdling on the moisture content of small-sized trees

The cost competitiveness of conifer stumps in the procurement of forest chips for fuel in Southern and Northern Finland

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