Material in this section originates from the following category in our Subject Index:
Biospheric Productivity (North America: Entire Continent)
Greening of the Earth (North America: Entire Continent)
Productivity (Biosphere: North America, Entire Continent)
Material preceded by an asterisk (*) was posted after this subject summary was written and therefore is not included in the summary. This material will be integrated into the summary at a later date.