If you were a leaf, what would you do in the face of Global Climate Change?

Sarah Neihaus is interested in nutrient cycling and how tropical forests will react to increased levels of carbon dioxide in the air.  People before her have shown that when there is more CO2 in the air, trees produce more leaf-litter (leaves that dry up and fall off the tree then collect on the ground).  She is interested in what effect more leaves on the ground might have on the cycles of the nutrients and the growth of the forest.

She thinks that having more carbon in the soil, which comes from having more leaf litter on the ground, will effect the nutrient cycle, but she is not yet sure how.  To find out what is happening, she is measuring carbon amounts at different places in the cycle.

She works on a large area of land that has been divided into smaller plots.  There are three different things happening in three different sections. In the first section, there are five plots of land that are untouched – just left as they are. Scientists call these control groups.  In the second section, there are five plots that have all of the leaves raked out of them every week!  These leaves are spread out as evenly as possible in the third section.  So, one section is natural, one section has the leaves raked out and the third section has extra leaves. If it sounds like a lot of work– you’re right!  They have a full-time leaf-raker just to maintain those sections.

Sarah collects her data in several different ways.  One is by collecting leaves as they fall to the ground with a square net trap held up with PVC tubes.  She dries everything that falls into the trap, grinds it up, and sends it to a lab where they identify the nutrient levels in the leaf litter.  The second way Sarah is collecting data is using a pizza pan!  She puts the pan down on the ground and then cuts around the  circumference of the pan to collect the leaf litter that is on the ground below the pan.  She cleans those samples, dries them, and sends them to a lab to find out their nutrient levels.

On these plots, she is looking at tree growth and nutrient cycling, because those two things are related to Global Climate Change.  Is this sort of study something we could do in Milwaukee? 

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