Novel extracting methods for conifer stumps

Laitila, Juha; Poikela, Asko; Ovaskainen, Heikki; Väätäinen, Kari

doi:10.1080/14942119.2019.1564614

Cited by 7 publications

(13 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hofsten et al 2012). The stump drill was also faster for most stump sizes than the modified crusher grapple recently studied by Laitila et al (2019) when harvesting Norway spruce stump on mineral soil. However, time consumption was still much higher than for Norway spruce harvesting with stump rakes on mineral soils (Kärhä 2012;Palander et al 2015).…”

Section: Time Consumptionmentioning

confidence: 73%

“…Estimated time consumption (s) per kg dry substance (DS) when harvesting Scots pine stumps. The DS for harvesting Scots pine stumps in the studies by Athanassiadis et al (2011), von Hofsten et al (2012, and Laitila et al (2019) was calculated according to Hakkila (1972), assuming that 53% of the stump and root system was harvested by the head studied by von Hofsten et al (2012), Laitila et al (2019), and the stump drill in our study. The time consumption was assumed to be equal when harvesting Scots pine as when harvesting Norway spruce.…”

Section: Time Consumptionmentioning

confidence: 95%

“…Currently, tree stumps are mainly harvested in Finland, and focused on Norway spruce (Picea abies) dominated clear cuttings on mineral soil (Laitila et al 2019). Stump harvesting is done during the ground frost and snow-free parts of the year, after logging residues (branches and tops) have been forwarded from the site (Laitila et al 2008(Laitila et al , 2019Anerud 2010). Harvesting is typically conducted using 20-25 t excavators (Kärhä 2012) fitted with a special stump rake (Laitila et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…However, the prototype needed modifications in order to achieve efficient stump harvesting. More recently Laitila et al (2019) investigated a modified crusher grapple for harvesting the central part of Norway spruce stumps on mineral soil. Although, the ground disturbance of this head has not yet been assessed, the disturbance might be similar to those determined by von Hofsten (2014).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of ground disturbance of frozen peatland during stump harvesting using a stump drill and rake

Berg

Nurmi

Prinz

2019

Scandinavian Journal of Forest Research

View full text Add to dashboard Cite

Tree stumps could be a source of renewable energy, contributing to a reduced dependence on fossil fuels. In Finland, stumps are currently harvested when the ground is not frozen to avoid co-removal of large amounts of soil and stones. Hence, the machinery used for stump extraction is not operated year-round. On peatlands, stumps could potentially be harvested when the ground is frozen. However, peatlands are highly sensitive to ground disturbance. There is, therefore, a need to identify equipment that causes low ground disturbance. In this study, peatland ground disturbance at stump level caused by stump harvesting using either a stump drill or a conventional stump rake was evaluated and compared in winter conditions. Results show that the stump drill caused up to 90% less ground disturbance per harvested stump than the conventional stump rake, but harvested 32-53% of the stump wood. Additionally, the size and shape of the disturbed areas changed between the harvesting year and following year, indicating that frost heaving plays a role in filling holes caused by stump extraction. The stump drill also consumed similar time to the conventional stump rake when harvesting Scots pine stumps on mineral soils, but far more when harvesting Norway spruce stumps.

show abstract

Section: Time Consumptionmentioning

confidence: 73%

Section: Time Consumptionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of ground disturbance of frozen peatland during stump harvesting using a stump drill and rake

Berg

Nurmi

Prinz

2019

Scandinavian Journal of Forest Research

View full text Add to dashboard Cite

show abstract

“…While new devices have been tested, excavators equipped with a specially designed harvesting head are generally used for roots and stump harvesting from final fellings (see Laitila et al 2019). While the degree of mechanisation is high in the Nordic countries, particularly in Finland, manual operations are more common in other parts of Europe.…”

Section: Díazmentioning

confidence: 99%

Improving performance and energy efficiency of biomass supply through machine alteration and organisational redesign

Prinz¹

2019

Diss. For.

View full text Add to dashboard Cite

This thesis summarises the findings of four case studies focussing on the redesign of specific aspects of the forest chip supply chain, the use of alternative terminals for chip supply, the interdependencies of chipper and chip trucks and the performance of individual machines after machine alteration. The aim of the work was to analyse and improve the fuel economy and energy efficiency of the forest chip supply system by modifying the settings of CTL harvesters, investigating the performance of an innovative hybrid chipper, introducing alternative supply systems through the use of a feed-in terminal and an analysis of forest chip supply systems under selected operational and environmental conditions. The analysis of the case studies involved individual machines and the entire forest chip supply system. Two study methods were used: work study and discrete event simulation (DES). Work study carried out to investigate the performance of individual machines and their alteration; the DES method was used for investigating the organisational redesign of the forest fuel supply system. The study resulted in the following findings and conclusions: 1) extreme machine settings have a statistically significant impact on the fuel economy of CTL harvesting machines; 2) hybrid machine technology can improve the fuel consumption and energy efficiency of chipping operations in forest chip production; nevertheless the productivity of the analysed prototype was below that for compared traditional chippers; 3) as an alternative to the direct supply of forest chips, the effect of utilising terminal operations on the overall supply cost can be quantified; terminal use improves the annual use of the supply fleet and enhances fuel supply security to the plant thereby reducing the need for supplementary fuel and 4) applying different types of types of chipper and truck-trailer combinations, supply costs and efficiencies can be quantified and vehicles with increased carrying capacity can improve the cost competitiveness. In the study an integrated approach taking physical, technological, enterprise and industrial levels of energy efficiency into account is proposed. Thereby state-of-the-art forest technology and current biomass supply ideally can be upgraded to achieve new, improved levels of performance and energy efficiency.

show abstract