What happens to peat during bog fires? Thermal transformation processes of peat organic matter

V. Ozols, I. Silamikele, L. Kalnina, D. Porshnov, L. Arbidans, J. Krumins and M. Klavins*

University of Latvia, Faculty of Geography and Earth Sciences, Department of Environmental Sciences, Raina blvd. 19, LV 1586 Riga, Latvia
*Correspondence: maris.klavins@lu.lv

Abstract:

Bog fires are a serious natural phenomena. Major increase in the number of fires has happened during the last decades due to bog transformation into agricultural lands, accidents and human activities. During bog fires the peat is exposed to high temperatures due to which chemical transformation and even mineralisation of peat can occur. The aim of the study was to analyse the impacts of the bog fires on the bog as an ecosystem, advance the understanding and knowledge of fire impact on peat and humic matter properties and application possibilities. As the material for the study peat samples from burnt sites and thermally treated peat were used. To reveal peat transformation during bog fires, thermogravimetric analysis of peat samples were done, where amounts of bitumens, humic acids and mineral matter were estimated. During bog fires thermal modification of peat properties takes place, resulting in full mineralisation of peat and release of mineral substances. Bog fires lead to development of peat char, bitumens and significant changes in structure and properties of peat humic acids. However, from perspective of application of peat as a substrate and from perspective of impacts on the bog ecosystems, the effects are negligible.

Key words:

Wood ash – green energy production side product as fertilizer for vigorous forest plantations

D. Lazdiņa*, I. Bebre, K. Dūmiņš, I. Skranda, A. Lazdins, J. Jansons and S. Celma

Latvian State Forest Research Institute ‘Silava’, Riga str. 111, LV-2169 Salaspils, Latvia
*Correspondence: dagnija.lazdina@silava.lv

Abstract:

Notable amounts of wood ash containing plant macro and micronutrient elements in balanced proportions are produced in Latvia. If bioenergy production source product is plant material, and facilities are operating well, then ‘side product’ fermentation residues or wood ashes should not contain elements in toxic concentrations. Wood ash contains P and K which are lacking in acidic organic soils and could work as fertiliser as well as a long term liming agent, besides that, all micronutrient elements necessary for physiological processes are present in wood ash. Wood ash could also be used as ‘revitalization agents’ – fertilisers to improve the growth of plantation forests. The aim of this research is to find and describe the positive effect of wood ash fertilisers on Norway spruce (Picea abies) and other economically valuable tree species. Research results show positive wood ash application effect on tree growth and vitality within the first 4 years when used for recultivation and revitalization purposes. Recycling of wood ash (0.5–3 t ha- 1 before planting) for fertilisation of and Picea abies forest plantations are a sustainable and effective solution for the improvement of tree growth as well as an environmentally safe method of utilization of bioenergy production residues.

Key words:

fertiliser, Norway Spruce, recultivation, regeneration, revitalization, soil amendment, wood ash