Book excerpt: Globally, tropical forests are highly productive ecosystems and play a critical role in sequestering anthropogenic carbon dioxide (CO2) from the atmosphere, accounting for up to half of the terrestrial biosphere's carbon sink. For reasons not yet fully reconciled, there are indications that the carbon sink strength of these forests is slowly declining, thereby decreasing the buffering capacity that these forests offer in mitigating global climate change. It is recognized that ecosystem nutrient limitations play an important regulatory role in plant growth, therein affecting ecosystem carbon...