Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere

• Published in: Nature (London) 2001-05, Vol.411 (6836), p.469-472
• Main Authors: Oren, Ram, Ellsworth, David S., Johnsen, Kurt H., Phillips, Nathan, Ewers, Brent E., Maier, Chris, Schäfer, Karina V.R., McCarthy, Heather, Hendrey, George, McNulty, Steven G., Katul, Gabriel G.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Atmosphere; Biological and medical sciences; Biomass; Carbon; Carbon - metabolism; Carbon dioxide; Carbon Dioxide - metabolism; Carbon sequestration; Carbon sinks; Cycadopsida; Ecosystem; Ecosystems; Forest ecosystems; Forestry; Forests; Fundamental and applied biological sciences. Psychology; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Humanities and Social Sciences; letter; multidisciplinary; Nitrogen; Nitrogen - metabolism; Nutrients; Science; Science (multidisciplinary); Soil fertility; Soils; Synecology; Terrestrial ecosystems; Trees - growth & development; Trees - metabolism; Water
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/35078064

Northern mid-latitude forests are a large terrestrial carbon sink 1 , 2 , 3 , 4 . Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO 2 ) fertilization are expected in these forests 5 . Yet, forests are usually relegated to sites of moderate to poor fertility, where tree growth is often limited by nutrient supply, in particular nitrogen 6 , 7 . Here we present evidence that estimates of increases in carbon sequestration of forests, which is expected to partially compensate for increasing CO 2 in the atmosphere, are unduly optimistic 8 . In two forest experiments on maturing pines exposed to elevated atmospheric CO 2 , the CO 2 -induced biomass carbon increment without added nutrients was undetectable at a nutritionally poor site, and the stimulation at a nutritionally moderate site was transient, stabilizing at a marginal gain after three years. However, a large synergistic gain from higher CO 2 and nutrients was detected with nutrients added. This gain was even larger at the poor site (threefold higher than the expected additive effect) than at the moderate site (twofold higher). Thus, fertility can restrain the response of wood carbon sequestration to increased atmospheric CO 2 . Assessment of future carbon sequestration should consider the limitations imposed by soil fertility, as well as interactions with nitrogen deposition.