I certainly do hope that trees are mysteriously able to access more nitrogen and phosphorus to support the hypothesized carbon fertilization effect that the carbon cycle models project. (julesandjames.blogspot.ru)
Even if carbon fertilization does influence forest growth, other factors — heat, drought, nutrient availability — could overwhelm it. (sciencemag.org)
And taken globally, increases in tropical forest carbon may be at least partly explained not by carbon fertilization, but by a recovery of carbon after past disturbances such as fire (both natural and anthropogenic) and land clearing by humans even centuries earlier - a factor that will reduce sink strength over time as forests recover. (ecotope.org)