Imagine an artist's sketchbook where the sketches represent the flow of matter and energy. That's exactly what system diagrams are! They use boxes to indicate storages of matter and energy, and arrows to show the flow between these storages. Pretty cool, right?

These are marked on arrows and can be of two types - transfer and transformation.

• Transfer processes: These are like tourists! They love traveling through the system and usually involve a change in location. They don't change their identity - just where they are!
• Transformation processes: These are like caterpillars turning into butterflies. They involve changes in state, phase, or form into new products within the system. For instance, when plants use light energy to make glucose through photosynthesis, that's a transformation process.

If you have data, you can show the size of storages and the magnitude of flows. The bigger the flow, the wider the arrow; the bigger the storage, the larger the box.

Now, let's picture this using the concept of forest carbon cycling. Imagine a forest as a big box containing 283 gigatonnes (a gigatonne is a billion tonnes - massive, right?) of carbon in living trees and plants. Dead wood, litter, and soil - our underfoot and overlooked friends - also have their box with even more, about 520 GtC.

• Atmospheric Carbon and Forests: We have another huge box - the atmosphere - with approximately 750 GtC. Forests breathe too, releasing about 60 GtC into the atmosphere yearly. Plus, when forests are cut down - particularly in the tropics - about 1.6 GtC more per year joins the party in the atmosphere.
• Carbon Capture: It's not all outgoing, though! When we plant other crops where forests used to be, they act like vacuum cleaners, sucking in some carbon from the atmosphere.

So, you see, systems are a dynamic balanceof different processes. They might seem complicated at first, but once you start viewing them like an interconnected web, they become fascinating!