ABSTRACT
This chapter considers the forest ecosystem, which plays the greatest role in the carbon dioxide balance of any vegetation. Forests are important because of photosynthesis, which can be considered to be a process that involves the conversion of solar energy, with a re-circulation of materials and an energy flow. One more important fact is that in mature natural forests the accumulated carbon returns to the earth after the trees die because of fires, volcanic activity, changes in the earth’s crust, old age, or disease. There is a common perception that the substitution of firewood with fossil fuels such as coal would be linked to an increase in carbon dioxide emissions. The majority of the carbon in tropical rainforests is present in vegetation, and even in tropical regions 70% of nutrient elements such as nitrogen are contained within the soil, with most contained in the surface layers at depths between 0 and 30 cm.
