Carbon is stored in all parts of the forest. The plant biomass actively binds carbon through photosynthesis. This is eaten by the animals and thus temporarily stored in them, after which the carbon cycle continues in the dying biomass and decomposition.

The carbon sink function of a forest is therefore only given to the extent that carbon remains bound in the system and is not removed by other decomposition (such as combustion). Therefore, the forest is not always a_{CO2 sink -} if more wood is removed and burnt than grows back, or if the soil is drained in such a way that the litter layer decomposes, the forest can also become a_{source of CO2} .

Figures are difficult to determine from the literature, as every forest ecosystem is different and subject to constant change.

Literature:

Federal Environment Agency (ed.) (2012): Reporting under the United Nations Framework Convention on Climate Change and the Kyoto Protocol 2012 National Inventory Report on the German Greenhouse Gas Inventory 1990 - 2010. p.482. at: https://www.umweltbundesamt.de/sites/default/files/medien/461/publikationen/4292.pdf (last accessed on 08.05.23)

Federal Statistical Office (2021): Number of the week No. 40 of 5 October 2021 at: https://www.destatis.de/DE/Presse/Pressemitteilungen/Zahl-der-Woche/2021/PD21_40_p002.html (last accessed on 08.05.23)