A characterisation of the ash content of conifer stump wood hogfuel

Alejandro Nieto Gámez, Enda Coates, Brian Cronin, Tom Kent

Research output: Contribution to journalArticlepeer-review


A study was carried out in the south-east of Ireland in which stumps were harvested on two conifer clearfell sites: a peat soil site and a peaty gley site. The stumps were harvested by excavator machines with a stump harvesting head which split and shook the stumps during excavation in order to remove soil. The stumps were stored on the site for a period of 9 to 10 months to further reduce soil contamination by weathering. The stumps were forwarded to the roadside and comminuted into hogfuel with a shredder. Samples were collected and prepared in three ways: clean stumpwood, hogfuel as received, and sieved hogfuel. The clean stumpwood was collected from stumps with a chainsaw prior to shredding. The hogfuel as received was collected from the shredder. The sieved hogfuel was prepared using an oscillating screen sieve with sieves ranging between 1 mm and 63 mm circular holes. The samples were analysed for ash content using a muffle furnace, and gross calorific values using an oxygen bomb calorimeter. Results have allowed for the comparison of clean stumpwood and hogfuel as received, which identifies the proportion of ash content associated with soil contamination, and that which is inherent to stumpwood. Results also describe the ash content and calorific value along the particle size distribution, and describe which particles, and thus the proportion of the fuel, need to be sieved out in order to increase the fuel quality to an acceptable condition.

Original languageEnglish
Pages (from-to)67-72
Number of pages6
JournalBulletin of the Transilvania University of Brasov, Series II: Forestry, Wood Industry, Agricultural Food Engineering
Publication statusPublished - 2017


  • Ash content
  • Sieving
  • Stump harvesting


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