What would happen with an increase of plants on earth?

I don't think much would change more animals would have lot of food and we would have lot of air

Well, it all depends on how much the plant increase is I would say it be fine maybe even beneficial up until a 39%  increase I would  say then that the plants would be taking up a dangerous amount of space but below would probably be better for certain rarity's of flowers such as blossoms and bloomers during the time.

ecotourism pay for conservation efforts.