BVOC emission variability for Norway spruce (Picea abies) in Hyltemossa, Sweden

Sammanfattning: Biogenic volatile organic compounds (BVOC) are known as hydrocarbons emitted into the atmosphere from the biosphere. They have physiological and ecological functions such as communication within the plant and plant – plant, protection against environmental stress factors and defense against herbivores attack. Coniferous forests are known to produce larger quantities of BVOCs, especially terpenes, where isoprene and the group of monoterpenes are the main compounds. Emitted BVOCs are highly reactive and have an impact on the atmospheric chemistry where it contributes to particle formation and growth. Hence, BVOCs mediate the relationship between the biosphere and atmosphere. Produced BVOCs are affected by environmental factors, among these factors are temperature, stress and light. Emissions may be induced in response to biotic and abiotic factors such as increased temperature, damage done by other organisms or air pollutants. The analysis of this thesis presents the relationship between BVOC emissions and the photosynthetic rate, and how the different compounds are affected by different environmental factors such as light. This was achieved by using a flow-through conifer chamber technique combined with a portable photosynthesis system combined with adsorbent tubes to trap the BVOC emissions. Where the result revealed the differences in compounds, emission rate and photosynthetic activity. Isoprene and the group of monoterpenes, including nine different compounds were then chosen BVOCs for this study. The results from this thesis were then compared to other published literature focusing on Norway spruce (Picea abies) stands during the growing season. This study based on measurements in 2019 showed increased emission rates compared to another study from the same stand four years prior to this, indicating induced emission from stress. The emission rates for the seasonal average were 2.35 (± 3.83 std) for isoprene and 3.59 (± 3.24 std) for monoterpenes, these results were in line with other published research for Norway spruce.