Last chapters of LOTR, after the victory. The heroes come back at home and it is destroyed, no nature, no trees, and a big factory in the middle. Takes magic to restore the natural ecosystem.
It takes Samwise Gamgee, a devoted and skilled gardener, spending a year of his life planting new trees to replace the ones that were lost.
Yes, he uses a magical resource he was given as part of his reforestation campaign, but it just speeds up the growth. The real factor is still Sam's tireless labor.
I was just being pedantic about the events of the narrative, because it's close to my heart.