Terrestrial carbon dynamics: Case studies in the former Soviet Union, the conterminous United States, Mexico and Brazil

• Published in: Mitigation and adaptation strategies for global change Vol. 1; no. 4; pp. 363 - 383
• Main Authors: Cairns, Michael A., Winjum, Jack K., Phillips, Donald L., Kolchugina, Tatyana P., Vinson, Ted S.
• Format: Journal Article
• Language: English
• Published: 1997
• Subjects: Mexico; USA
• ISSN: 1381-2386; 1573-1596
• DOI: 10.1007/BF00464888

This research assessed land-use impacts on C flux at a national level in four countries: former Soviet Union, United States, Mexico and Brazil, including biotic processes in terrestrial ecosystems (closed forests, woodlands, and croplands), harvest of trees for wood and paper products, and direct C emission from fires. The terrestrial ecosystems of the four countries contain approximately 40% of the world's terrestrial biosphere C pool, with the FSU alone having 27% of the global total. Average phytomass C densities decreased from south to north while average soil C densities in all three vegetation types generally increased from south to north. The C flux from land cover conversion was divided into a biotic component and a land-use component. We estimate that the total net biotic flux (Tg/yr) was positive (=uptake) in the FSU (631) and the U.S. (332), but negative in Mexico (-37) and Brazil (-16). In contrast, total flux from land use was negative (=emissions) in all four countries (TgC/yr): FSU -342; U.S. -243; Mexico -35; and Brazil -235. The total net effect of the biotic and land-use factors was a C sink in the FSU and the U.S. and a C source in both Brazil and Mexico.