Changing atmospheric carbon dioxide: A threat or benefit?

Atmospheric carbon dioxide (CO2) concentrations are rapidly increasing, having risen by about 100 ppm over the last century. Atmospheric CO2 is the basic photosynthetic building block of plants and is respired to generate the plant\u27s energy. Atmospheric CO2 in enhanced conditions is like an all-you-can-eat buffet for trees. But are there hidden threats from rising atmospheric CO2? Are the world\u27s forests sinks or sources of CO2? What will they be in the future? Can we slow the rise in atmospheric CO2 with more intensive forestry efforts? How effective can intensive forestry practices be in sequestering carbon? Simultaneous with increasing CO2, other greenhouse gases such as NOx and O3 are also rapidly increasing in the atmosphere. Will these gases be beneficial or detrimental to trees under elevated CO2? This chapter will address these questions and will use our current understanding of forest function to gain insight into how future forests will be affected by increasing greenhouse gases. Finally, we address the potential of afforestation, reforestation, agroforestry and forest management for increasing carbon sequestration. © 2003 Elsevier Science Ltd. All rights reserved