What do we need forests for?

Human activities and drought threaten large stocks of carbon in forests (Shown here, Sumatra).

This week, Science takes a closer look at the world's forests and how they influence the environment around us. On Earth, there are approximately one trillion canopy trees alone, and they form the top layer of the world's forests, absorbing the largest amount of sunlight. These canopy trees consist of about 100,000 different species, and their forests serve as homes for about two thirds of all the land-dwelling creatures on the planet.

Forests also play a large role in global climate change. In many ways, the world's forests act as the planet's lungs, breathing in huge amounts of carbon dioxide and exhaling oxygen back into the atmosphere. In fact, Earth's forests absorb billions of tons of carbon dioxide gas each year, including about 30 percent of the carbon dioxide gas that humans put into the air.

Carbon sinks in tropical forests (shown here in Borneo), removing large amounts of atmospheric carbon dioxide from human activities.

These forests affect the world around us in so many ways, making it extremely difficult to understand the consequences of how we treat them. Currently, the world's forests are changing in ways that will affect us directly, through deforestation, logging, pollution, the loss of many pollinating and seed-spreading animals, and increased amounts of carbon dioxide from human activity that make the world warmer.

Researchers say we can treat forests in ways that will help minimize global climate change and keep the amounts of oxygen and carbon dioxide in the air at healthy levels. They are proposing many new ways to conserve our forests, re-grow healthy forests, and also provide products from the forests like timber, fiber, and energy in ways that will help the planet as well as the people who live and work in forests. But it will take more government action from around the world, and a strong desire of the people to protect the planet, for these plans to be successful.

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More information about the world's forests is in the 13 June issue of the journal Science.