Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Sprite is sugar, water and carbon dioxide. The sugar is like the nutrients that the roots have stored, and are sending into the canopy so the leaves have more energy to build more plant tissue. The CO2 out gases so fast it is useless. The water is critical to keeping the leaves moist through the season, when the roots have been cut.
Aquarium ferts (N, P, K, micros) are like the fertilizer that the roots pick up from the soil and send into the canopy so the leaves have the raw materials to build more plant tissue.
Excel is a carbon substitute for aquatic plants. Picked up via the leaf instead of CO2.
Since the goal of a cut tree is not to grow, but simply to stay moist enough not to be a fire hazard, I would skip any of the above, and just make sure plenty of water is available. If you have a live, potted tree that you will be placing in the garden, then the aquarium ferts would be best, but not much of them. Water is, again, the most needed thing.
I might be wrong; maybe there are studies showing that cut trees take in more water if there is an additive. More water = better fire resistance.