Trees and forests are like icebergs, where the part you can see is far less than the sum of everything that's going on. And as with an iceberg, the part you can't see can be important. I work with measurements of processes that are largely invisible, like photosynthesis and transpiration, but can be measured and can tell us important things about a forest will respond to something like fertilization or climate change. The tools we use measure these invisible processes and help us to build budgets for carbon and water, which allow us to explain and predict forest responses to change.