The rain forests of South America are very active photosynthetic zones. Although plants around the world use photosynthesis, these areas are more productive than other parts of the planet. a) About half of the forests that covered the Earth in the early 1900s have been cut down. Discuss the impact this has on carbon dioxide levels in the atmosphere. Support your answer. Products Reactants Sunlight energy + 6H20 + 6CO2 CH120, +602 Look back at the reaction for photosynthesis. Trees that are cut down can no longer photosynthesize. (4 points) b. Why might rain forests in South America and near the equator be so productive? List two reasons. Think about the climate and weather near the equator and in a rain forest. (4 points)