Ikenge, Cameroon

Continuing south along the 8th meridian, you enter a hot and humid room. In a matter of minutes, you can feel your hair begin to curl from the moisture. At 9º 6' E/ 5º 16' N, you are in an equatorial band of rising warm moist air that feeds water vapor into the Hadley cells of Earth’s atmosphere. The climate here is tropical.

You hear the sound of water trickling in rivulets and dropping from the tips of leaves splashing against the ground. In the distance, lightning flashes and thunder rolls across the tangle of roots and vines as you make your way across the forest and jungle floor. Here the trees make the rain through the process of evapotranspiration.

Plants remove carbon dioxide from the atmosphere and release oxygen and water as waste products of photosynthesis. Water released through pores in plant leaves (stomata) evaporates into the atmosphere. In the tropics, there is little variation in daily temperature and hours of sunlight. Therefore, plants keep their leaves for long periods of time unlike trees in northern hemisphere forests that develop leaves in the spring and lose leaves in the fall (deciduous trees). Carbon dioxide levels in northern hemisphere diciduous forests fluctuate with changes in leaf cover. However, tropical rainforest photosynthesis and evapotranspiration rates show little to no seasonal variation. Their continuous uptake of atmospheric carbon dioxide has earned rainforests the nickname “lungs of the earth.” A secondary benefit of continuous leaf coverage is lower carbon dioxide production from decomposition of fallen leaves on the forest floor. Looking down you observe roots and vines, but no leaf litter.

By land coverage, 10% of Africa’s rainforests are found in Cameroon. Cameroon’s rainforest ecosystem is part of the second largest rainforest in the world - the Congo Basin Rainforest. Plant biodiversity in African rainforests is limited compared to Southeast Asian or South American rainforests. In this oldest rainforest of Africa, some trees have survived through multiple ice ages of the current era. Natural processes of death and decomposition have created open spaces in the rainforest where ground cover of can flourish. You climb through a tangle of roots and vines. It’s a jungle in here!

Closing your eyes, you hear the sounds of a multitude of animals calling into the night. Tantalus monkeys, mandrills, chimpanzees, bats, birds, and rodents flourish in multiple layers of the rainforest and in the jungle. Although plant diversity in African rainforests is lower than rainforests in other regions, animal diversity, especially rodent and bird species is high. The longlived trees store carbon and provide multiple levels of habitat for animals. Over long periods of time, African rainforests have been explosed to more fluctuations in temperature and rainfall than Asian or Amazonian rainforests. The plants and animls found in modern African rainfosrests are descendents of species adapted to warmer, drier conditions.

Water drains into a twisting rushing river teeming with fish. Crocodiles laze on the shorelines waiting for the opportune moment to strike at unsuspecting prey. Like Axel Werner, you find the only way across the river is a shaky suspension bridge. Unlike Werner, you have a choice to go around rather than cross the bridge, but your inner explorer is up to the challenge.

The bridge is a narrow wooden plank suspended above the water by a network of thick ropes. Although a misstep or insufficient balance for Werner would have meant a dangerous and likely fatal plunge into the swirling river below the bridge, you are only likely to have wet shoes if you slip. It’s tempting to try to balance by holding the top of the suspension rope, but doing so makes the plank less stable. The best way to go from one side to other with dry shoes is to stand straight and walk one foot in front of the other using your arms for balance. As challenging as the crossing seems, inhabitants of Ikenge can walk confidently carrying heavy loads on their heads.

At night, it is probable that animals take advantage of the bridge to cross the river and avoid becoming a crocodile’s dinner. If this is happening, then the bridge is acting as a biodiversity corridor between the two sides of the river.

Arriving in Ikenge, you explore the village listening to the sound of rain beating on the tin roofs. A film from B.Z. Goldberg’s camera shows children playing in the rain dancing to the beat of drums. Water plays a central role in the lives of Ikenge residents. Men are in charge of hunting and external village security. Women run daily life in the village, and they take care of children. Through video, you meet Alexander, the village elder who leads Ikenge. In addition to being the village decision making authority, he is a living pharmacopeia of natural medicines that can be sourced in the rainforest. Although low in plant diversity, the African rainforest is rich in medicinal plants, some of which grow in no other location.

The sound of chainsaws in the distance is evidence of a threat to biodiversity and to the water cycle and atmospheric carbon dioxide balancing processes of the African rainforest. As you exit Cameroon, the chainsaws grow louder and the crack and thud of falling trees accompanies images of logging taking place in the rainforest.

The future of this valuable climate controlling biome remains an open question as Cameroon works with other African nations involved in the AFR100 program. Historical evidence shows that African rainforests expand during periods of higher levels of carbon dioxide and warmer temperatures. However, periods of drought or changes in precipitation patterns cause rainforests to shrink. Deforestation and reforestation represent additional factors in predictions of climate change in the region. The future role of African rainforests in the cycling of carbon and water remains an area requiring more research and careful management of human activities. Will the African rainforest continue to reduce the impact of turning on a light bulb in Bremerhaven?

Look for clues to answer the question.

• Examine the photo to identify factors that influence the climate of Ikenge.

• Use Google Earth to develop a sense of place.

• Analyze the data and the climograph to observe patterns in rainfall and temperature.

• Use the dig deeper resources to gather information to understand the processes behind climate change.