CO2 and Plant Growth
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Elevated Carbon Dioxide Making Arid Regions Greener
A study of arid regions around the globe finds that a carbon dioxide “fertilization effect” has caused a gradual greening from 1982 to 2010. The satellite imagery data showed an 11 percent increase in foliage after adjusting the data for precipitation, air temperature, the amount of light, and land-use changes during the study period when CO2 concentrations increased by 14 percent.
"Satellites are very good at detecting changes in total leaf cover, and it is in warm, dry environments that the CO2 effect is expected to most influence leaf cover.”
The Aerial Fertilization Effects of CO2 and its Implications
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This study by Dr. Sherwood Idso shows that the world's forests increase their rates of carbon sequestering by 2.8 times in response to a 300 ppm increase in the CO2 content in the air. After two years of growth in a controlled experiment, trees in an ambient plus 300 ppm CO2 enriched environment were 2.8 times larger than the trees without CO2 enrichment.
Tree and Forest Functioning in an Enriched CO2 Atmosphere
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This abstract shows that elevated levels of atmospheric CO2 causes a long-term biomass increase of 130% for conifer trees and 49% for deciduous trees in studies not involving stress components. However, stimulation of photosynthesis by elevated CO2 in long-term studies was similar for conifers (62 %) and deciduous trees (53 %).
Happy Holidays, Thanks to CO2
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This World Climate Report discusses the results of three recent studies that investigated the effects of elevated atmospheric CO2 on sugarcane and pine trees. Doubled CO2 levels increased the sugarcan leaf area by over 30 percent, while the all important juice from the main stem increased a whopping 83%. Hundred of articles have already shown that pine trees will grow larger, more resistant to drought and other stresses, and more water-use efficient thanks to elevated atmospheric CO2. Shannon LaDeau and James Clark of Duke University examined results from a 13-year old loblolly pine plantation in the Duke Forest of North Carolina. They conclude “We found that trees growing under elevated CO2 matured earlier and produced more seeds and cones per unit basal area than ambient grown trees.”
The Effect of Long-term Atmospheric CO2 Enrichment on the Intrinsic Water-use Efficiency of Sour Orange Trees
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This study evaluated the water use efficiency of orange trees at Phoenix, Arizona in response to elevated atmospheric CO2. The trees increased their water-use efficiency by 80% in response to a 300 ppmv increase in CO2, which is identical to the long-term CO2-induced increase in the trees’ production of wood and fruit biomass. This suggests there could be little to no change in total water-use as trees' productivity increases with the air’s CO2 content .
