Browsing by Author "Tiusanen, Kirsi"

Continuously progressive climatechange has built a need for sustainable energy source. In the near future we need an alternative source to fossil fuels. At the same time we should secure lower carbon emissions to the atmosphere and increase carbon sinks and accumulate bigger carbon pools to biosphere.Wood based second-generation biofuels are potential option for a sustainable source of energy and therefore an alternative for fossil fuels and also for first-generation biofuels which are produced from food suitable sources. The high cellulose content of wood drives the use as an energy source but long investment time to raw material production impairs the wood’s possibility to be a quick solution to current climate and energy challenges. Hybrid aspen (Populus tremula x tremuloides) as a fast growing tree is one of the species under research to produce cellulose faster. Institute of Biotechnology at University of Helsinki has developed a method for gene manipulation of aspen to enhance the cambial development and tree growth which would shorten the rotation time of harvesting raw material. Simultaneously we need to predict possible side effects that may come with the use of gene manipulation. The wood based production of bioenergy creates a sink for atmospheric carbon dioxide until logging. Furthermore many of the Populus species including aspen emit biogenic volatile organic compounds (BVOC) which slow the climate change due to the secondary particle (SOA) formation. This study investigates seasonal BVOC emission profile and concentration of aspen Populus tremula in natural forest environment during years 2010, 2011 and 2013. The other part of the study concentrates on emissions from gene manipulated hybrid aspen species Populus tremula x tremuloides in greenhouse environment. The results will show the seasonal profile of BVOC emissions and other trace gas exchange (CO2 ,H2O) and their concentration on leaf level. Small part of the atmospheric carbon that tree takes in as CO2 is released back in air as BVOCs and based on these results from three year time aspen releases carbon 0.44-0.57 %per year as BVOVs. The emission profiles show clearly that temperature and light conditions affect to BVOCemission volume. Furthermore, the leaf development phase has a huge effect on seasonal emission profile. The other part of the study that investigate the differences in BVOC emissions between genetic manipulated trees and control trees. Based on these measurements there is no significant difference in BVOC emissions between gene manipulated and wild type hybrid aspen on leaf level. Since environmental conditions affect emission profile and volumes, the climate change with increasing temperature may increase aspen’s seasonal BVOC emissions. Based on measurements of this study the potential use of gene manipulated aspen does not increase BVOC emissionson leaf level but on canopy level the result may be different.