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Technology and systems for stump harvesting with low ground disturbance

Berg, Simon (2014). Technology and systems for stump harvesting with low ground disturbance. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2014:95
ISBN 978-91-576-8138-6
eISBN 978-91-576-8139-3
[Doctoral thesis]

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Tree stumps could make a significant contribution to the transition from a fossil- to a bio-based economy, but current stump harvesting operations have adverse ecological effects. The ground disturbance caused by the up-rooting leads to increased carbon emissions from the soil and increases risks of leaching of heavy metals and nutrients, while removal of stump wood increases nutrient removal and reduces amounts of dead wood in the forest. However, the ground disturbance could be reduced by introducing new techniques. The overall objective of the studies this thesis is based upon was to investigate possible future systems for stump harvesting capable of reducing ground disturbance, and estimate their economic sustainability. Studies were based on experimental field studies and simulations. The ground disturbance depends on the type of harvesting head, as harvesting the whole stump creates more disturbance than harvesting the central part of the stump; the ground disturbance is also larger on peat soil than on mineral soil, but does not depend on time since clear cutting; and the root breakage diameter is surprisingly small (5-30 mm) after whole stump harvests and is not affected by the time since clear-cutting. Twisting stumps loose requires large torques and cannot be considered a viable way of extraction. The ground disturbance and cost to industry was estimated for four systems: a conventional whole stump harvesting system (WSH), a stump centre harvesting (SCH) system and two possible future systems for integrated harvest and forwarding of stem and stump centres with separation of the stump centres at either the landing (IHL) or industrial sites (IHI). The IHI and SCH systems are estimated to be up to 100 % and 60 % more costly, respectively, than WSH. However, costs of IHL were estimated to be similar with WSH for large trees. WSH (up-rooting) caused five times more ground disturbance per hectare compared to the other systems. In conclusion, the conventional up-rooting system was estimated to be best from an economic perspective, but caused more ground disturbance then harvesting of stump centres only. If ground disturbance restrictions are introduced, and new technologies are developed accordingly, costs of utilizing stump wood will be higher than at present. In development of integrated stump centre harvesting systems, as described here, it is crucial to design techniques and methods that minimize possible risks of damaging the stem wood in order to secure timber quality. Finally, regardless of future regulations, whole stump up-rooting technologies will still be warranted for treating stands infected by root rot.

Authors/Creators:Berg, Simon
Title:Technology and systems for stump harvesting with low ground disturbance
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2014
Depositing date:14 November 2015
Number of Pages:83
I.Berg S & Nordfjell. Effect of stump size and timing of stump harvesting on ground disturbance and root breakage diameter. (manuscript).
II.Berg S, Bergström D, Athanassiadis D & Nordfjell T (2012): Torque required to twist and cut loose Scots pine stumps. Scandinavian Journal of Forest Research 27(8), 724-733.
III.Berg S, Bergström D & Nordfjell T (2014): Simulating conventional and integrated stump- and round-wood harvesting systems: a comparison of productivity and costs. International Journal of Forest Engineering DOI: 10.1080/14942119.2014.941640
IV.Berg S, Prinz R & Nurmi J. Comparison of ground disturbance caused by using a stump drill and a stump rake on frozen peatland. (manuscript).
Place of Publication:Umeå
Publisher:Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8138-6
ISBN for electronic version:978-91-576-8139-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:stumps, stump removal, forest trees, boreal forests, wood residues, tree felling equipment, timing, costs, environmental impact, leaching, sweden
Keywords:integrated harvest, system cost, root breakage diameter, nutrient removal, fuel consumption
Permanent URL:
ID Code:11641
Faculty:S - Faculty of Forest Sciences
Department:(S) > Department of Forest Biomaterials and Technology (from 131204)
External funders:Energimyndigheten and Jämtkraft AB and Skellefteå Kraftaktiebolag and Swedish District Heating Association
Deposited By: Simon Berg
Deposited On:17 Nov 2014 10:41
Metadata Last Modified:02 Dec 2014 11:09

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