Journal Articles

See the latest peer-reviewed journal articles published in partnership with the Utah Biomass Resources Group.

Mobile Pyrolysis for Hazardous Fuels Reduction and Biochar Production in Western Forests

McAvoy, D.J., Dettenmaier, M., and Kuhns, M.R. 2018. Mobile pyrolysis for hazardous fuels reduction and biochar production in western forests, Journal of Extension, February, 2018, Vol 56/No. 1/Ideas at Work/ 1IAW3.


Mobile pyrolysis is a novel approach to fuels reduction. In this article, we address the experiences of the Utah Biomass Resources Group in developing mobile pyrolysis technologies and generating the products derived from pyrolysis of woody biomass—biochar, bio-oil, and syngas. We describe development of a mobile pyrolysis platform for biomass conversion demonstration, its use in a series of demonstrations conducted in several western states, and the usefulness of the resulting products. Additionally, we discuss our outreach and communication efforts to date and speculate on the future of the technology.

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Methods to reduce forest residue volume after timber harvesting and produce black carbon

Page-Dumroese, D., Busse, M.D., Archuleta, J.G., McAvoy, D.J., and Roussel, E. 2017. Methods to reduce forest residue volume after timber harvesting and produce black carbon. Scientifica. 2017: Article ID 2745764. 


Forest restoration often includes thinning to reduce tree density and improve ecosystem processes and function while also reducing the risk of wildfire or insect and disease outbreaks. However, one drawback of these restoration treatments is that slash is often burned in piles that may damage the soil and require further restoration activities. Pile burning is currently used on many forest sites as the preferred method for residue disposal because piles can be burned at various times of the year and are usually more controlled than broadcast burns. In many cases, fire can be beneficial to site conditions and soil properties, but slash piles, with a large concentration of wood, needles, forest floor, and sometimes mineral soil, can cause long-term damage. We describe several alternative methods for reducing nonmerchantable forest residues that will help remove excess woody biomass, minimize detrimental soil impacts, and create charcoal for improving soil organic matter and carbon sequestration.

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Preliminary Screening of the Effect of Biochar Properties and Soil Incorporation Rate on Lettuce Growth to Guide Research and Educate the Public Through Extension

Hunter, B., Cardon, G.E., Olsen, S., Alston, D.G., and McAvoy D.J. 2017. Preliminary screening of the effect of biochar properties and soil incorporation rate on lettuce growth to guide research and educate the public through Extension. Journal of Agricultural Extension and Rural Development, Vol.9 (1), pp. 1-4, January 2017.


Extension service of the land grant university system is often the first source of public information for emerging soil amendments such as biochar. Biochar is a charcoal product made by heating plant biomass via pyrolysis and is increasingly marketed as an organic soil amendment. As energy producing pyrolysis industries expand, there is increasing opportunity to utilize locally produced biochar for its potential value in sustainable agriculture. However, the highly variable properties of biochar materials and their effects on plant growth and soil nutrient supply make it difficult to objectively study the effect of this soil amendment and provide guidance to users of locally sourced biochar materials. Therefore, preliminary screening studies are needed to identify potentially beneficial ranges of biochar properties and their effects on soils and plants that can then be rigorously tested in field research. The role of extension in conducting such screening studies is invaluable to providing both guidance to researchers in developing sound study methods, and in educating the public on biochar and the myriad of uncertainties surrounding its use; thereby establishing the need for rigorous research on its properties. In 2014, a simple, yet informative screening trial was performed to identify optimal biochar pyrolysis production temperature, conditioning (that is, degree of crushing) and soil application rate for future field experiments. Lettuce (Lactuca sativa, var. Parris Island Cos) chosen for its short growth period and rapid biomass development, was grown in 9-L pots filled with silt loam field soil amended with biochar and/or fertilizer (or none) made from Utah-sourced cherry wood. The pots were uniformly drip irrigated once daily to keep them near field capacity throughout the study period, thereby eliminating any influence of differential soil-plant-water relations. Three biochar products created from the same cherry wood source, but resulting from three different pyrolysis temperatures (375, 475 and 575°C) and either powder ground (P) or masticated (M) texture were applied to soil at three application rates (1, 2 and 3% by weight). Variation in plant dry weight at harvest within and among treatments was high. Lettuce growth with the addition of biochar was decreased as compared to control treatments in all cases, except for biochar produced at the lowest temperature, 375°C. Results indicate that masticated biochar produced at 375°C and applied to soil at the rate of 2% by mass offers the best combination of beneficial response and ease of handling for future field evaluations. This case study’s benefit for demonstrating the value of preliminary screening trials to inform both future research and public outreach education is discussed.

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Co-firing of pulverized coal with pinion pine/juniper wood in raw, torrified and pyrolyzed forms

Nelson, M. & McAvoy, D.J. 2013. Exploring solutions to pinyon and juniper expansion and densification through Biomass Field Days. Journal of National Association of County Agriculture Agents.


A program was funded by the U.S. Forest Service to perform pilot-scale co-firing studies at the University of Utah in a 1.5 MW pulverized-coal test facility, to examine the emissions, deposition behavior and ash characteristics, when co-firing pulverized coal with wood culled from pinion–juniper (P–J) forests in Utah.

The woody material was evaluated in each of three forms: 1) raw, untreated material; 2) torrefied material, and 3) biochar from the pyrolysis of the P–J material. The different types of the thermally processed P–J material were produced by Amaron Energy in a 1/2 t per day prototype pyrolysis facility prior to the testing at the University of Utah. 

Results of the pilot-scale co-firing trials indicated essentially no major differences in gaseous emissions or unburned carbon in flyash or baghouse ash when co-firing pulverized coal with any of the 3 biomass fuels for the conditions investigated. In addition, no significant deposition problems would be anticipated using 5–10% biomass on a thermal input basis. Operation with 10% or greater percentage of raw or torrefied wood resulted in feeding problems at this scale; however, the bio-char could be fed with no problems for levels as high as 20% (the highest percentage tested).

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Exploring Solutions to Pinyon and Juniper Expansion and Densification Through Biomass Field Days

Nelson, M. & McAvoy, D.J. 2013. Exploring solutions to pinyon and juniper expansion and densification through Biomass Field Days. Journal of National Association of County Agriculture Agents.


Pinyon and Juniper (PJ) trees are taking over rangelands in the western U.S. Currently there are nearly 50 million acres of PJ woodlands and more acres are being expanded into each year. Utilization of woody biomass generated from forest treatments can provide jobs, stimulate the local economy and ultimately reduce the cost of forest treatments. Southern Utah Woody Biomass, a loosely knit organization of private individuals and government personnel has come together to promote the development of harvesting techniques and the utilization potential of PJ biomass. Since October 2010 three field days have been hosted in southern Utah. Over $7.5 million in equipment has been demonstrated and exhibited. Field day attendees include 715 people from 18 states, Canada, and China. The field days demonstrated different methods of harvesting in PJ woodlands and looked at ways of adding value to the harvested trees. Leading experts in the woody biomass and forestry industry addressed the importance of restoring woodlands and ways for industry and government to partner to address the problem.

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