Cedar Creek: What Does a Global Warming Experiment Look Like?


We're having a typical day be about 3 degrees warmer fahrenheit or about 5 degrees or so warmer fahrenheit throughout the whole growing season. Then we start looking at what individual plants do. We look at what's called their phenology. We ask when does the first leaf come out on a plant, when does it first flower and sort of follow the major phases in the life of a plant throughout the growing season. We can then use that to see how temperature is influencing their life. Then as the season progresses we look at the abundances of the plant species and ask have they changed from last year and is this change associated with the temperature that we're imposing on them. We also measure the flux of carbon dioxide out of the soil into the air or out of the air into the soil. Every year we take soil cores where we'll go down a meter into the soil with a metal tube, pull the soil core out, do many cores per plot and then we analyze those for their content of carbon and nitrogen and also for the amount of roots in the soil and for the chemistry of the roots.

This again let's us follow what's happening to carbon and nitrogen in these plots. Soil carbon is a very important part of global carbon cycle. So this is a very important thing for us to do. After we've harvested biomass to try to understand the abundance of the species We have to sort it to species, we dry it, we weigh it, we do chemistry on it. That'll be in the autumn. In the plots themselves in the autumn we'll observe what is happening to the abundances but without doing destructive sampling. We'll estimate how abundant different species are to try to look at them in a different growing season. The midsummer is one growing season but there are other plants that actually do very well in the early autumn. That are not very abundant at all in the summer. They come up and they have their peak abundance in the cool, wetter time of the autumn. By the end of November, we turn off the heat lamps and we have a few months of normal winter that they experience..