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Tree growth in carbon dioxide enriched air and its implications for global carbon cycling and maximum levels of atmospheric CO 2
Author(s) -
Idso Sherwood B.,
Kimball Bruce A.
Publication year - 1993
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/93gb01164
Subject(s) - carbon dioxide , carbon dioxide in earth's atmosphere , environmental science , photosynthesis , carbon cycle , atmosphere (unit) , cycling , atmospheric carbon cycle , respiration , carbon respiration , carbon fibers , atmospheric sciences , environmental chemistry , chemistry , ecology , carbon sequestration , botany , ecosystem , negative carbon dioxide emission , biology , forestry , meteorology , geography , geology , mathematics , algorithm , composite number
In the longest carbon dioxide enrichment experiment ever conducted, well‐watered and adequately fertilized sour orange tree seedlings were planted directly into the ground at Phoenix, Arizona, in July 1987 and continuously exposed, from mid‐November of that year, to either ambient air or air enriched with an extra 300 ppmv of CO 2 in clear‐plastic‐wall open‐top enclosures. Only 18 months later, the CO 2 ‐enriched trees had grown 2.8 times larger than the ambient‐treated trees; and they have maintained that productivity differential to the present day. This tremendous growth advantage is due to two major factors: a CO 2 ‐induced increase in daytime net photosynthesis and a CO 2 ‐induced reduction in nighttime dark respiration. Measurements of these physiological processes in another experiment have shown three Australlian tree species to respond similarly; while an independent study of the atmosphere's seasonal CO 2 cycle suggests that all earth's trees, in the mean, probably share this same response. A brief review of the plant science literature outlines how such a large growth response to atmospheric CO 2 enrichment might possibly be maintained in light of resource limitations existing in nature. Finally, it is noted that a CO 2 “fertilization effect” of this magnitude should substantially slow the rate at which anthropogenic carbon dioxide would otherwise accumulate in the atmosphere, possibly putting an acceptable upper limit on the level to which the CO 2 content of the air may ultimately rise.