Global climate change: Threat for the vitality of northern conifers?
2003
Utriainen, J. (University of Kuopio (Finland))
Abstract Several human activities have influenced the global climate, and the increases in atnrospheric greenhouse gas concentrations as well as the rise in surface mean temperature are part of the resulting global climate change. Carbon dioxide (CO2), methane (CH4) and tropospheric ozone (O3) are the most important greenhouse gases at the present time. In predicted future climate conditions, the increases in atmospheric CO2 and tropospheric O3 concentrations are regarded as important factors in plant responses. In spite of a number of experiments investigating the impact of changing climate on vegetation, long-term combined effects under the natural growth conditions are still poorly understood. This paper reviews the present comprehensions concerning the increases in tropospheric O3 and atmospheric CO2 concentrations and the rise in surface mean temperature as stress factors for the physiology of trees, focusing on the effects in most common northern conifers, Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Since the soil in northern coniferous forests is typically in shortage of available nitrogen (N) in rural areas, but exposed to N excess in most populated regions, the role of N availability as an interactive factor in plant O3 and CO2 responses is also discussed in this review. Additionally, most commonly used experiment facilities for evaluating the effects of air pollutants on trees are briefly introduced.
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