Vertical force requirement for stump lifting

Czupy, I.; Horváth-Szováti, E.

doi:10.17221/4/2013-jfs

Cited by 6 publications

(2 citation statements)

References 4 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The stumps are uprooted and split using a tracked excavator, and impurities are shaken off by the crane movements Lazdins et al 2009;Lindroos et al 2010;Athanassiadis et al 2011;Tolosana et al 2011;Kärhä 2012;Berg et al 2012;Czupy and Horvath-Szovati 2013;Berg et al 2014;Berg 2014). Shaking off the impurities from the extracted stumps take a relatively large proportion of the excavator's working time, and stump shaking by the crane movements also causes stress to the driver (Laitila 2008;Kärhä 2012).…”

Section: Procurement Of Stumps and Delimbed Stems For Fuelmentioning

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.

View full text Add to dashboard Cite

• 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.

show abstract

Section: Procurement Of Stumps and Delimbed Stems For Fuelmentioning

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.

View full text Add to dashboard Cite

show abstract

“…16). Salīdzinot celmu raušanas ražīguma rādītājus ar līdzīgiem pētījumiem Ziemeļvalstīs, kuros salīdzinātas dažādus celmu raušanas kausus, konstatēts, ka Latvijā iegūti būtiski labāki ražīguma rādītāji.…”

unclassified

Technology for extraction and transportation of coniferous stumps = Technology for extraction and transportation of coniferous stumps

Zimelis¹

View full text Add to dashboard Cite

Zimelis A. Technology for extraction and transportation of coniferous stumps: PhD thesis - Salaspils: Latvian State Forest Institute (LSFI) ‘Silava’ and Jelgava: Latvia University of Life Sciences and Technologies, 2020, 75 p. The thesis contains of 19 tables and 29 figures. Stump harvesting has been well studied in Scandinavian countries. More detailed studies on stumps as a renewable wood energy resource have been carried out since 1970ies. From the beginning this type of wood resource was linked with planned supply materials for pulp mills. For instance, in Finland for the last couple of decades the extraction of stump wood is carried out as a source for biofuel where in 2005 more than 0.4 mil m3 of raw material was used in the cogeneration cycle. First extensive studies in Latvia were done in 2006 where experimental stump harvesting have been performed in JSC ‘Latvian State Forests’ and LLC ‘Rīgas Meži’. In the past this raw material was used in chemical industry for extraction of rosin, turpentine and their further refined products. In this thesis the assessment of available stump wood energy resources was made using the data from State forest register (SFR) and National forest inventory (NFI). After summarizing abovementioned data, more than 103 thousand GWh of primary energy resource from stumps in clear-cuts of coniferous have been detected. Technically extracted annual amount of primary energy corresponds to 349 GWh. According to the Latvian forest typology largest amount of biomass was detected in Hylocomiosa and Oxalidosa forest types. The majority of available resources 62% can be obtained in state forests and 38% in other forests. To characterize the efficiency of stump extraction in common technological process, in this study all previous studied sites where stump harvesting for biofuel purposes was performed in the territory of Latvia. In total data from 3022 stumps were included. During the modelling process, in which energy efficiency parameters were detected, a need for additional information on soil preparation and stump harvesting was detected. Furthermore, theoretical calculations were started to model the stump operational process under different scenarios. These calculations were based on theoretical mechanical rules where technical stability is detectable, which is mainly depended on diameter on removable stump and site-specific location. Mostly, these two factors are crucial, where technical parameters such as excavator unladen weight, required hydraulic flow and other important parameters should be changed. Based on abovementioned calculation, in this study the elaboration and approbation of particular methods for stump pulling and crushing was done. In the result of this study, it is suggested that the most effective technological approach of stump extraction using MCR 500 II stump lifting head (in additional, this feature is made in Latvia) with medium class forwarder (in this particular study John Deere 810D forwarder is included). Furthermore, for stump grinder it is suggested to use, for instance, CBI Magnum Force 6800P where delivery of grinded wood to the final consumer would be performed by the truck with a capacity at least 90 m3 (in this study the Volvo FM truck is included). The use of this technology scheme, the total amount of energy efficiency factor ir 3.9. This explains the fact that the amount of energy obtained from further use of the wood extracted from stumps will be higher compared to the amount of energy supplied in the extraction process. The main results of the thesis are published in 11 scientific papers and based on research results two Latvian patents have been developed and approved for stump pull and crush, and soil preparation as a part of forestry technology.

show abstract