When a tree is cut down, does the amount of carbon inside the tree stay the same, increase or decrease?

When you cut down a tree, its roots remain in the ground. They absorbed carbon too, and for most trees that is a considerable fraction of their total mass. The decay of roots over time leave much of the carbon as part of the soil structure, so that remains fixed for long times.

The leaves, needles, seeds, cones, twigs and other parts will have become part of the topsoil too. Over the life of a tree, much more carbon is stabilized than just what is in the cut tree.

The wood from trees that have been cut down may get used in buildings and other products that can last for centuries.

Explanation:

the transfer for conduction is the heat transfering from the liquid to the spoon

the transfer for convection is the heat rising from the liquid to the air

the transfer for radiation is the heat going through the sides of the cup and to the air

at least that is what i would do