Most studies use tree seedlings, or only last for two to three years.
I mentioned my interest on the rhizosphere responses to elevated CO2, and the direction of my research paper will be focused in this area. We discussed some of the effects of increased CO2 levels on plant roots and on interactions and processes that occur in the rhizosphere. It was determined that there is more carbon fixed as a result of leaf or canopy-level photosynthesis in systems exposed to elevated CO 2 than can be accounted for in plant biomass OR in soils. If global changes modify the rates of processes differentially, soil C storage will be altered. Researchers have found that both the woody root and the fine root component of the tree's root-system are more productive under elevated CO2.