Forests and the atmosphere  The greenhouse effect is a natural
phenomenon whereby gases in the atmosphere trap heat which would
otherwise be radiated into space. Without this greenhouse
effect, the average temperature of the earth would be about 30 C
lower than it is.  However, the proportion of greenhouse gases
in the earth's atmosphere, especially carbon dioxide (CO2), is
increasing as a result of human activities. Emission of fossil
fuels combustion accounts for about 65 percent of the additional
carbon dioxide (CO2) currently found in the atmosphere, while
the other 35 percent is derived from deforestation and the
conversion of natural ecosystems into agricultural systems.
Forests play an important role in the global carbon cycle and
help to protect the atmosphere and mitigate climate change.
Young forests act as a major carbon sink because carbon dioxide
(CO2) is taken up from the atmosphere and used to produce the
carbohydrates, fats, and proteins that make the trees grow.
Carbon uptake is greatest in