A new study by an international research team shows that the growth of trees seems to be limited by cell growth rather than photosynthesis The study was published in the journal Science on May 12 and was supported by the U.S. Department of energy, the U.S. Department of agriculture, the National Science Foundation, the David and Lucille Packard foundation and the Arctic sustainable development challenge II.
The study is also of surprising significance. At present, forests absorb and store a large part of our current carbon dioxide emissions. If forest growth slows, so will the ability of trees to absorb carbon and mitigate climate change. In addition, the study found that photosynthesis and tree growth have different responses to different climate cues, which indicates that the existing forest carbon sequestration models may overestimate the capacity of forests to store carbon in the atmosphere. These results emphasize the importance of considering mechanisms other than photosynthesis when predicting how much carbon trees can store.
Forests collect and store atmospheric carbon through photosynthesis as woody biomass and soil carbon. This technology currently offsets about 25 per cent of anthropogenic carbon emissions per year. With the increase of carbon dioxide (CO2) in the atmosphere, photosynthesis is promoted through a phenomenon called carbon fertilization. Using trees to absorb carbon is generally considered to be an attractive natural method to deal with climate change.
It has always been believed that photosynthesis and plant growth are usually limited by the carbon content in the atmosphere. The more carbon, the more growth, and the more storage. However, an increasing number of studies have shown that this may not be the case, indicating that forest carbon storage is sensitive to other factors, including temperature, water and nutrient supply. This means that forest carbon sequestration is a major source of uncertainty in the prediction of global forest carbon sequestration potential.