Carbon, climate, and North America's oldest boreal trees
In an age of unprecedented high atmospheric carbon dioxide levels, the question of whether or not plants and trees can utilize excess carbon through photosynthesis is one of paramount importance. Researchers have observed what has been called the CO2 fertilization effect, whereby plants' rates of photosynthesis increase in response to higher levels of CO2 in the atmosphere, although this is thought to be dependent on various other factors such as temperature, moisture, nutrient availability, etc. A group of researchers from Quebec sought to better understand how the oldest boreal trees in North America—Thuja occidentalis L, white cedar—have responded to higher levels of atmospheric CO2 (ca) in terms of these trees' intrinsic water use efficiency (iWUE).