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Forces required to vertically uproot tree stumps

Lindroos, Ola and Henningsson, Marina and Athanassiadis, Dimitris and Nordfjell, Tomas (2010). Forces required to vertically uproot tree stumps. Silva Fennica. 44 :4 , 681-694
[Research article]

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Stumpwood attracts renewed interest due to increased use of forest biomass for bioenergy. In Nordic countries stumps are generally uprooted with crawler excavators, which have strong cranes (ca. 400 kNm gross lift torque), but are not designed for moving in forest terrain. Their use is based on practical experience with available and tested machine types rather than thorough examinations of requirements, partly due to limited knowledge of force requirements for uprooting of stumps. Therefore, in this work mean and maximum forces required to vertically uproot stumps of Norway spruce (Picea abies) and birch (Betula spp.) were quantified together with the effects of various soil types and uprooting methods. The used excavator’s crane-mounted uprooting device enabled comparisons between usage of solely crane force, and a method in which preparatory loosening forces were applied prior to crane force. Uprooting stumps in single pieces proved difficult; 61% split unintentionally. Force requirements were similar across tree species, increasing curve-linearly with stump diameter, and stumps uprooted in a single piece required more force than split stumps. Preparatory loosening reduced crane force requirements and, surprisingly, less force was required to uproot stumps from a mesic, till soil than from a moist, finer-textured soil. No stump required more than 60 kN crane force and functions for maximum force requirements indicate that powerful harvesters and forwarders (gross crane lifting capacity of 273 and 155 kNm, respectively) should be able to uproot all stumps with ≤ 61 cm and ≤ 32 cm diameter, respectively, in one piece. Larger stumps could be managed if it is acceptable that stumps are split before uprooting.

Authors/Creators:Lindroos, Ola and Henningsson, Marina and Athanassiadis, Dimitris and Nordfjell, Tomas
Title:Forces required to vertically uproot tree stumps
Series Name/Journal:Silva Fennica
Year of publishing :2010
Page range:681-694
Publisher:The Finnish Society of Forest Science, The Finnish Forest Research Institute
Additional Information:Sveaskog AB and SRG Carrier Systems AB kindly provided forest ground and machinery for the study. Financial support was received from the Swedish research program Efficient Forest Fuel Supply Systems (ESS).
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Full Text Status:Public
Agris subject categories.:J Handling, transport, storage and protection of agricultural products > J12 Handling, transport, storage and protection of forest products
K Forestry > K11 Forest engineering
P Natural resources > P05 Energy resources management
P Natural resources > P06 Renewable energy resources
Keywords:stump harvesting, machine development, bioenergy, forest fuels, Picea abies, Betula spp
Permanent URL:
Alternative URL:http://www.metla.fi/silvafennica/abs/sa44/sa444681.htm
ID Code:8221
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
Deposited By: Ola Lindroos
Deposited On:05 Jul 2011 11:30
Metadata Last Modified:12 Sep 2017 07:13

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