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Read the articles and learn more about carbon cycle, abiotic factors and interaction between climate and forests.

  • Abiotic environmental factors
    The movements of Earth in relation to the Sun generate a strong annual cycle of radiation and temperature that further affects other environmental factors such as soil moisture and air … Read more
  • Air humidity
    The water holding capacity of air depends sharply on the air’s temperature (i.e. the warmer the air is, the more water it can hold). At a given temperature, air is … Read more
  • Air temperature
    The diurnal and annual cycle in solar radiation is reflected into air temperature by the absorption of solar radiation. The annual cycle in the radiation generates the annual cycle in temperature. … Read more
  • Carbon cycle
    The capture and release of carbon dioxide (CO2) by the forest is the net result of many biological processes. The green parts of plants perform the first and most important … Read more
  • CO2 concentration
    In the Northern Hemisphere, the CO2 rises in the winter and declines in the summer, mainly as a response to the seasonal activity of forests, other land vegetation and algae which … Read more
  • Forests
    A greenhouse gas is a gas in the atmosphere that absorbs and emits radiation within the thermal infrared range causing the greenhouse effect. Carbon dioxide (CO2) is one of the … Read more
  • How to measure photosynthesis?
    There are plenty of methods available to measure photosynthesis. The method we use is actually a measurement of the carbon dioxide catch:  We enclose a small part of the tree … Read more
  • How to measure soil respiration?
    The measuring concept is actually quite simple. We place a chamber on a small soil surface area and follow the change in CO2 concentration of the air in this chamber. The … Read more
  • How to model photosynthesis?
    Many years of measurements have provided a lot of information on the behaviour of the forest, how it photosynthesizes, transpires and respires. We know more or less what to expect the tree will … Read more
  • How to model soil respiration?
    Years of measurements have produced a lot of information on soil respiration. We know more or less how the respiration rate is related to changing environmental conditions, as plant respiration … Read more
  • Lifetime of a forest
    Species composition in forests is mainly driven by climate (which determines air temperature), and by latitude (which determines light intensity). However, natural plant communities influence the present environment as well. … Read more
  • Measuring shoot respiration
    We measure the shoot respiration by the same measurement setup as photosynthesis. Trunk respiration needs a special measurement chamber. Root respiration cannot, however, be measured directly. We derive the root … Read more
  • Modelling shoot respiration
    Years of measurements have produced a lot of information on plant respiration. We know more or less how the respiration rate is related to the changing environmental conditions. In principle, … Read more
  • Photosynthesis
    Photosynthesis is the most fundamental process in plants because it provides raw material for growth and stores energy for later use in vital functions. In photosynthesis, the energy of solar … Read more
  • Plant respiration
    Plant needs energy for growth, transport and maintenance of vital functions as animals do. To get the energy required, they oxidize (i.e. burn the photosynthetically fixed sugars). At the same … Read more
  • Soil moisture
    Water plays an important role in the biological and chemical processes occurring in the soil. Together with soil temperature, they affect carbon and nitrogen cycles in forests. The soil of … Read more
  • Soil respiration
    The carbon used for ecosystem growth (net primary production, NPP) is eventually transferred to the soil in litter fall, root turnover and death of individual plants. In addition, trees notably … Read more
  • Soil temperature
    Soil temperature follows the changes in the air temperature with a time lag that increases with soil depth. Close to the soil surface, the variation in temperature is larger than, … Read more
  • Solar radiation
    Sunlight makes photosynthesis possible.  From all the available light that comes from the sun, green plants are able to use most efficiently the visible light (wavelength range 400 to 700 … Read more
  • Stomata action
    Gases enter and leave the leaf through stomata, which actively control the gas exchange of CO2 and H2O, for example, between the plant and the atmosphere. Plants need to keep the … Read more
  • The measuring station, SMEAR II
    Hyytiälä Forestry Field Station, located in Juupajoki, Southern-Finland, is a unit of the Department of Forest Sciences in the University of Helsinki. Its mission is to enable forestry teaching and … Read more
  • Transpiration
    Plants lose water meanwhile carbon dioxide enters plant leaves through stomata, the small pores on the leaf surface. The release of water is called transpiration. It is a passive flow that … Read more
  • Year in a forest
    The dynamics of a boreal forest throughout the year is strongly marked by the seasonality of the subarctic climate, which is the climatic area in the world where boreal forests … Read more