At the end of the entire process, he only gained a 10% increase in strength. It wasn't huge, but it increased his potential by several folds. His cultivation would now be at least twice as fast because of the new hearts and perfectly assembled mana paths.
All the spare mana was sitting around the tree, actually in its trunks and roots. A faint blue hue could be seen around his body. Azir took them away so they wouldn't get caught for whatever she was going to do.
What happened was that large amounts of earth began to fall into the hole, and dozens of giant blocks fell without stopping, similar to rain. Within a few minutes, the huge hole around him was completely closed.
"POFT!"
The tree fell to the ground and its roots began to pierce the earth. Then grass began to grow around him at high speed; every second, it advanced a few kilometers and in just a few more minutes it covered the entire devastated area again.