{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T19:18:35Z","timestamp":1777663115167,"version":"3.51.4"},"reference-count":53,"publisher":"American Association for the Advancement of Science (AAAS)","issue":"5417","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Science"],"published-print":{"date-parts":[[1999,5,14]]},"abstract":"<jats:p>The concentration of atmospheric carbon dioxide was increased by 200 microliters per liter in a forest plantation, where competition between organisms, resource limitations, and environmental stresses may modulate biotic responses. After 2 years the growth rate of the dominant pine trees increased by about 26 percent relative to trees under ambient conditions. Carbon dioxide enrichment also increased litterfall and fine-root increment. These changes increased the total net primary production by 25 percent. Such an increase in forest net primary production globally would fix about 50 percent of the anthropogenic carbon dioxide projected to be released into the atmosphere in the year 2050. The response of this young, rapidly growing forest to carbon dioxide may represent the upper limit for forest carbon sequestration.<\/jats:p>","DOI":"10.1126\/science.284.5417.1177","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T09:42:20Z","timestamp":1027762940000},"page":"1177-1179","source":"Crossref","is-referenced-by-count":371,"title":["Net Primary Production of a Forest Ecosystem with Experimental CO\n            <sub>2<\/sub>\n            Enrichment"],"prefix":"10.1126","volume":"284","author":[{"given":"Evan H.","family":"DeLucia","sequence":"first","affiliation":[{"name":"Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jason G.","family":"Hamilton","sequence":"additional","affiliation":[{"name":"Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shawna L.","family":"Naidu","sequence":"additional","affiliation":[{"name":"Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Richard B.","family":"Thomas","sequence":"additional","affiliation":[{"name":"Department of Biology, West Virginia University, Morgantown, WV 26506, USA."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jeffrey A.","family":"Andrews","sequence":"additional","affiliation":[{"name":"Department of Botany,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adrien","family":"Finzi","sequence":"additional","affiliation":[{"name":"Department of Botany,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Lavine","sequence":"additional","affiliation":[{"name":"Institute of Statistics and Decision Science, Duke University, Durham, NC 27708, USA."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roser","family":"Matamala","sequence":"additional","affiliation":[{"name":"Department of Botany,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jacqueline E.","family":"Mohan","sequence":"additional","affiliation":[{"name":"Department of Botany,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"George R.","family":"Hendrey","sequence":"additional","affiliation":[{"name":"Biosystems Division, Brookhaven National Laboratory, Upton, NY 11973, USA."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"William H.","family":"Schlesinger","sequence":"additional","affiliation":[{"name":"Department of Botany,"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"221","reference":[{"key":"e_1_3_1_2_2","unstructured":"Technical Summary in Climate Change 1995 J. T. Houghton et al. Eds. (Cambridge Univ. Press Cambridge 1996) pp. 9\u201349."},{"key":"e_1_3_1_3_2","unstructured":"W. H. Schlesinger Biogeochemistry: An Analysis of Global Change (Academic Press New York ed. 2 1997)."},{"key":"e_1_3_1_4_2","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1007\/BF02861058","volume":"51","author":"Sharkey T. D.","year":"1985","unstructured":"Sharkey T. D., Bot. Rev. 51, 507 (1985);","journal-title":"Bot. Rev."},{"key":"e_1_3_1_4_3","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1007\/BF00014592","volume":"39","author":"Gunderson C. A.","year":"1994","unstructured":"Gunderson C. A., Wullschleger S. D., Photosynth. Res. 39, 369 (1994);","journal-title":"Photosynth. Res."},{"key":"e_1_3_1_4_4","doi-asserted-by":"crossref","first-page":"609","DOI":"10.1146\/annurev.arplant.48.1.609","volume":"48","author":"Drake B. G.","year":"1997","unstructured":"Drake B. G., Gonz\u00e1lez-Meler M. A., Long S. P., Annu. Rev. Plant Physiol. Plant Mol. 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L., Holocene 1, 168 (1991) ;","journal-title":"Holocene"},{"key":"e_1_3_1_7_4","doi-asserted-by":"crossref","first-page":"660","DOI":"10.1139\/x92-088","volume":"22","author":"Van Deusen P. C.","year":"1992","unstructured":"Van Deusen P. C., Can. J. For. Res. 22, 660 (1992);","journal-title":"Can. J. For. Res."},{"key":"e_1_3_1_7_5","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1007\/BF01105004","volume":"70","author":"Luxmore R. J.","year":"1993","unstructured":"Luxmore R. J., Wullschleger S. D., Hanson P. J., Water Air Soil Pollut. 70, 309 (1993) .","journal-title":"Water Air Soil Pollut."},{"key":"e_1_3_1_8_2","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1146\/annurev.es.21.110190.001123","volume":"21","author":"Bazzaz F. A.","year":"1990","unstructured":"Bazzaz F. A., Annu. Rev. Ecol. Syst. 21, 167 (1990).","journal-title":"Annu. Rev. Ecol. Syst."},{"key":"e_1_3_1_9_2","unstructured":"Three control and three treatment plots were installed in a loblolly plantation that was planted in 1983 on formerly agricultural land. The clay-rich ultic Alfisols in this region are of the Enon series and are low in available nitrogen and phosphorus. The density of pine trees is 1733 stems ha \u22121 and the forest has not yet initiated rapid self-thinning ["},{"key":"e_1_3_1_9_3","doi-asserted-by":"crossref","first-page":"586","DOI":"10.2307\/1310669","volume":"37","author":"Peet R. K.","year":"1987","unstructured":"Peet R. K., Christensen N. L., BioScience 37, 586 (1987);","journal-title":"BioScience"},{"key":"e_1_3_1_9_4","unstructured":"]. Silvicultural practices have not been applied and several hardwood species including sweetgum ( Liquidambar styraciflua L. 620 stems ha \u22121 ) yellow poplar ( Liriodendron tulipifera L. 68 stems ha \u22121 ) winged elm ( Ulmus alata Michx. 226 stems ha \u22121 ) and red maple ( Acer rubrum L. 207 stems ha \u22121 ) have established in the forest understory. Pine trees represent more than 98% of the total basal area. To control for topographic variation between plots (\u223c5 m) and potential gradients in site fertility we arranged the three ambient and three elevated CO 2 plots in a blocked design (three pairs)."},{"key":"e_1_3_1_10_2","doi-asserted-by":"crossref","first-page":"1551","DOI":"10.13031\/2013.27650","volume":"39","author":"He Y.","year":"1996","unstructured":"He Y., Yang X., Miller D. R., Hendrey G. R., Lewin K. F., Nagy J., Trans. ASAE (Am. Soc. Agric. Eng.) 39, 1551 (1996);","journal-title":"Trans. ASAE (Am. Soc. Agric. Eng.)"},{"key":"e_1_3_1_10_3","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2486.1999.00228.x"},{"key":"e_1_3_1_10_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0065-2504(08)60028-8","volume":"28","author":"McLeod A. R.","year":"1999","unstructured":"McLeod A. R., Long S. P., Adv. Ecol. Res. 28, 1 (1999).","journal-title":"Adv. Ecol. Res."},{"key":"e_1_3_1_11_2","unstructured":"The elevated CO 2 plots were fumigated for 81% and 79% of 1997 and 1998 respectively. Most of the nontreatment periods were to accommodate ancillary experiments and during extreme weather. The system provided reliable control of [CO 2 ] for \u226599% of the period of fumigation in 1997 and 1998. The annual average CO 2 enrichment at the center of each plot varied from 199 to 203 \u03bcl liter \u22121 above ambient concentrations and the maximum standard deviation of the annual mean CO 2 enrichment observed in any fumigated plot was 84 \u03bcl liter \u22121 ."},{"key":"e_1_3_1_12_2","unstructured":"Stainless steel dendrometer bands ["},{"key":"e_1_3_1_12_3","first-page":"742","volume":"42","author":"Hall R. C.","year":"1944","unstructured":"Hall R. C., J. For. 42, 742 (1944);","journal-title":"J. For."},{"key":"e_1_3_1_12_4","doi-asserted-by":"crossref","first-page":"2454","DOI":"10.1139\/x93-304","volume":"24","author":"Keeland B. D.","year":"1993","unstructured":"Keeland B. D., Sharitz R. R., Can. J. For. Res. 24, 2454 (1993);","journal-title":"Can. J. For. Res."},{"key":"e_1_3_1_12_5","unstructured":"] were installed on stems 1.4 m above the soil surface on 30 to 40 trees in each plot. The populations of sample trees in ambient and elevated CO 2 plots were normally distributed and the mean (\u00b11 SD) basal area per tree at the beginning of the experiment was not significantly different between ambient and elevated plots (ambient: 179.8 \u00b1 92.7 cm 2 ; elevated: 186.5 \u00b1 92.6 cm 2 ; P = 0.57)."},{"key":"e_1_3_1_13_2","unstructured":"Within the elevated and ambient groups RBAI changed \u22640.2% over the entire range of basal areas and therefore was considered independent of tree size."},{"key":"e_1_3_1_14_2","unstructured":"Regional estimates of drought expressed as the modified Palmer drought index were obtained from the National Oceanic and Atmospheric Administration National Climate Data Center."},{"key":"e_1_3_1_15_2","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1007\/BF00477095","volume":"64","author":"Strain B. R.","year":"1994","unstructured":"Strain B. R., Thomas R. 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Root turnover rates were calculated as annual mortality plus annual decomposition for the same period ["},{"key":"e_1_3_1_17_3","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1007\/BF00121422","volume":"41","author":"Persson H.","year":"1979","unstructured":"Persson H., Vegetatio 41, 101 (1979);","journal-title":"Vegetatio"},{"key":"e_1_3_1_17_4","doi-asserted-by":"crossref","first-page":"900","DOI":"10.1139\/x87-141","volume":"17","author":"Santantonio D.","year":"1987","unstructured":"Santantonio D., Grace J. C., Can. J. For. Res. 17, 900 (1987);","journal-title":"Can. J. For. Res."},{"key":"e_1_3_1_17_5","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1023\/A:1004313515294","volume":"200","author":"Vogt K. A.","year":"1998","unstructured":"Vogt K. A., Vogt D. J., Bloomfield J., Plant Soil 200, 71 (1998) ].","journal-title":"Plant Soil"},{"key":"e_1_3_1_18_2","unstructured":"Before initiating this experiment we harvested 30 pine trees (3.5 to 35.6 cm in diameter) from nearby stands to generate allometric regressions equating bole diameter to whole tree dry mass {woody roots bole branches and foliage ["},{"key":"e_1_3_1_18_3","doi-asserted-by":"crossref","first-page":"1116","DOI":"10.1139\/x98-083","volume":"28","author":"Naidu S. L.","year":"1998","unstructured":"Naidu S. L., DeLucia E. H., Thomas R. B., Can. J. For. Res. 28, 1116 (1998);","journal-title":"Can. J. For. Res."},{"key":"e_1_3_1_18_4","unstructured":"]}. The standing biomass of all trees in each plot at the beginning of the 1996 growing season was calculated from measured BA and these size-dependent allometric regressions. The values for all trees were summed to provide initial total standing biomass per plot. The diameter for all trees in each plot at the end of each year was calculated by multiplying the initial BA by the RBAI for sample trees and the allometric regressions were again used to calculate the final standing crop for each year. Previous research indicates that CO 2 enrichment does not alter the allometric relations for loblolly pine (15) or the root\/shoot ratio for other tree species (4)."},{"key":"e_1_3_1_19_2","unstructured":"The above-ground biomass of subcanopy trees was calculated from equations in"},{"key":"e_1_3_1_19_3","doi-asserted-by":"crossref","first-page":"138","DOI":"10.2307\/3543848","volume":"21","author":"Monk C. D.","year":"1970","unstructured":"Monk C. D., Child G. I., Nicholson S. A., Oikos 21, 138 (1970).","journal-title":"Oikos"},{"key":"e_1_3_1_19_4","unstructured":"and the coarse-root biomass was calculated from R. H. Whittaker and P. L. Marks in Primary Productivity of the Biosphere H. Lieth and R. H. Whittaker Eds. (Springer-Verlag New York 1975) pp. 55\u2013118."},{"key":"e_1_3_1_20_2","first-page":"1","volume":"10","author":"Crawley M. J.","year":"1983","unstructured":"Crawley M. J., Stud. Ecol. 10, 1 (1983);","journal-title":"Stud. Ecol."},{"key":"e_1_3_1_20_3","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1038\/361148a0","volume":"361","author":"Cyr H.","year":"1993","unstructured":"Cyr H., Pace M. L., Nature 361, 148 (1993).","journal-title":"Nature"},{"key":"e_1_3_1_21_2","unstructured":"D. E. DeAngelis R. H. Gardener H. H. Shugart in Dynamic Properties of Forest Ecosystems D. E. Reichle Ed. (Cambridge Univ. Press Cambridge 1981) pp. 567\u2013672;"},{"key":"e_1_3_1_21_3","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1016\/S0378-1127(96)03744-9","volume":"86","author":"McNulty S. G.","year":"1996","unstructured":"McNulty S. G., Vose J. M., Swank W. T., For. Ecol. Manag. 86, 241 (1996) .","journal-title":"For. Ecol. Manag."},{"key":"e_1_3_1_22_2","unstructured":"Monthly measurements of the efflux of CO 2 from the forest floor over 24 hours were made in four random locations in each ring with enclosed soda-lime traps ["},{"key":"e_1_3_1_22_3","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1016\/S0031-4056(23)03645-4","volume":"23","author":"Edwards N. T.","year":"1982","unstructured":"Edwards N. T., Pedobiologia 23, 321 (1982);","journal-title":"Pedobiologia"},{"key":"e_1_3_1_22_4","doi-asserted-by":"crossref","first-page":"1467","DOI":"10.1890\/0012-9658(1998)079[1467:CFMUSL]2.0.CO;2","volume":"79","author":"Grogan P.","year":"1998","unstructured":"Grogan P., Ecology 79, 1467 (1998);","journal-title":"Ecology"},{"key":"e_1_3_1_22_5","unstructured":"]. The total annual CO 2 efflux from the soil was calculated by integrating the area beneath these plots of the monthly measurements."},{"key":"e_1_3_1_23_2","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1007\/s004420050462","volume":"114","author":"Pan Y.","year":"1998","unstructured":"Pan Y., et al., Oecologia 114, 389 (1998).","journal-title":"Oecologia"},{"key":"e_1_3_1_24_2","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1038\/363234a0","volume":"363","author":"Melillo J. M.","year":"1993","unstructured":"Melillo J. M., et al., Nature 363, 234 (1993).","journal-title":"Nature"},{"key":"e_1_3_1_25_2","doi-asserted-by":"crossref","first-page":"666","DOI":"10.2307\/1942099","volume":"3","author":"Comins H. N.","year":"1993","unstructured":"Comins H. N., McMurtrie R. E., Ecol. Appl. 3, 666 (1993);","journal-title":"Ecol. Appl."},{"key":"e_1_3_1_25_3","unstructured":"; Y. Luo and J. F. Reynolds Ecology in press."},{"key":"e_1_3_1_26_2","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1046\/j.1365-2486.1999.00240.x","volume":"5","author":"Idso S. B.","year":"1999","unstructured":"Idso S. 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