Carbon uptake and storage (p. 5-6). (Kohlenstoffaufnahme und -speicherung)
Plants absorb carbon dioxide from the air through stomata (Spaltöffnungen) (1).
Together with light as an energy source, they build up carbohydrates (Kohlenhydrate) by means of photosynthesis (video, youtube) (Fig. 2). This enables their development and growth.
For the energy consumption of the plant metabolism, about half of the carbohydrates are "respired" again by the cells, and in the process carbon dioxide (CO2) is released (3).
The remaining carbon is stored in the form of various compounds in the biomass (2):
- in leaves and needles for hours to months (2a)
- in twigs and branches for years (2b)
- in the trunk for decades to centuries (2c)
- in the roots and soil for centuries to millennia (2d).
A large fraction of the biomass falls back to the ground as foliage and branches and is decomposed by microorganisms (4).
In the process, the carbon bound in it is released again in the form of CO2. When an old tree has finally decomposed, i.e. the trunk, leaves and branches have also decomposed, the uptake and release of carbon decomposed, the uptake and release of carbon is more or less balanced.
(DE-Dabei wird der darin gebundene Kohlenstoff in Form von CO2 wieder freigesetzt. Wenn ein alter Baum schliesslich verrottet ist, also Stamm, Laub und Äste ebenfalls zersetzt wurden, halten sich Aufnahme und Abgabe von Kohlenstoff etwa die Waage.)