Browsing by Subject "carbon storage"

Climate change severely threatens ecosystem services and human well-being: vegetation and soils underneath it can be particularly vulnerable to climate warming. Soils hold the largest carbon stock in terrestrial ecosystems, and urban park soils, especially in cool climates, can hold remarkable carbon stocks and may be able to offset some atmospheric CO2 emissions. Land use changes, such as urbanization, influence soil organic carbon formation and soil carbon storages. In this study, I was interested whether three vegetation types (deciduous trees, conifers and lawn) differ in their capacity to store C in their rhizosphere, and whether this is affected by park size. I measured the proportion of tree canopy layer in class A park areas of the city of Helsinki, to estimate soil C storages of these areas and to examine C density (kg C m-2). Proportions of tree canopy layers in different park size groups were measured using QGIS and ortographs. Soil C storages were calculated using existing soil C data and average proportions of conifer and deciduous trees in parks of the city of Helsinki. Park size had a significant effect on proportion of the tree canopy coverage: canopy cover decreases with an increase in park size. Especially large parks are dominated by lawn. The average soil C densities in small, medium and large parks were 23.98 kg C m-2, 23.47 kg C m-2 and 23.15 kg C m-2, respectively. However, the overall proportion of conifer canopy in parks of the city of Helsinki is rather small, resulting in small differences in C densities between different park size categories, despite significant differences in tree canopy coverage between the three size groups. Most of the stored soil C in parks of the city of Helsinki are under lawn, even though it is the least efficient of the three studied vegetation types (deciduous trees, conifers, lawn) in soil C sequestration. Within a park size category and at park level, large parks store the highest amount of carbon per park. Even so, at the city level, the total amount of carbon is highest in the small parks due to their high number. Conifer trees associate with improved C sequestration to soils compared to deciduous trees and lawn. Increasing the amount of conifer trees in urban parks thus likely increase the important C storages of these soils. Results of this study highlight the importance of the contribution of urban parks and especially conifer trees in carbon sequestration. Future research related to urban soil C sequestration and the effects of vegetation type and climatic conditions is needed to better understand soil C accumulation and how the C sequestration of urban park soils could be enhanced.

Climate change affects the human habitat and the mechanics that cause this scientific phenomenon are somewhat well known. This study examines how forest policy, agricultural policy and environmental policy can control the mechanisms that cause climate change. The material of the study consists of interviews of 12-13 Finnish experts, each representing one of the previously mentioned sectors. Each of the experts have been asked 13-14 questions about the importance of climate change mitigation, as well as the mechanisms by which agriculture and forests affect the climate and how climate change should be considered in environmental policy. The data was collected between October 8th and November 8th of 2019. This was in five weeks after the IPCC 1,5-degree climate report was published. A series of topics was constructed from the answers, and they are meant to be used as topics to be discussed in the Finnish 2019 parliamentary election. In addition, on how important scientific academics see the control of climate change, they were also asked how critical climate change is. The interview material is stored in the Finnish Social Science Data Archive (www.fsd.uta.fi) The experts’ answers to the importance of controlling climate change were almost unanimous and considered to be highly important. Carbon sink and storage were considered the most effective methods to control climate change. According to the results, the study proposes topics that should be discussed in politics and when a person wants to advance the control of climate change in forest, agriculture and environment politics. Political decisions are often based on value judgement, which again are based on the information of different methods efficacy. The results that are discussed in this study are not the only options, but they give guidelines and reasons for discussions related to effective choices. Forest policies should recognize the effects of forest industry to the development of carbon sink and storage. Forest industries prerequisite for operation and decision making in addition to considering employment and export industry, must also consider the effect for Finland’s net carbon emissions. Activities which lengthen the forest rotation time would have multiple positive benefits and increase forest carbon storage. Agricultural politics should broaden the discussion to reach food politics. Consumption habits have big effect on agricultural production structure and it can be directed by many ways. The structure of agricultural production should also be considered from the emission point of view, because the land use is substantially large and changes in production can affect Finland’s emission in a scale, that would have large effect on our nations net carbon emissions. To strengthen carbon sinks, landowners should have compensation mechanism methods, that increase carbon sinks, and which are combined to the size of the carbon storage. In environmental policy climate change must be paid more attention and governmental boundaries must not intervene significant decision making. The strengthening of the role of Ministry of the Environment and adding co-operation between different ministries supports the decision making regarding environmentally positive issues.