No, you're putting too much emphasis on Hadley cells. The air patterns are only one part of a very much more complex cycle. As the poster above you noted, for a

No, you're putting too much emphasis on Hadley cells. The air patterns are only one part of a very much more complex cycle. As the poster above you noted, for any given amount of water, the amount going into the air in a particular place is influenced by the density of plants. Plants pull water from underground and help evaporate it in one particular place. The evaporated air can then condense and become rain again. Therefore, very dense masses of plants can increase the rate with which water is pulled from the ground and then evaporate and then condenses into rain and then returns to the ground, starting the cycle over again. Remove the trees and you still have Hadley cells, but you won't have a rainforest anymore, if the density of the plants falls below some threshold -- you won't have as much rain, even though the Hadley cell is still there -- you might have the same amount of water, but the speed at which it evaporates, and therefore becomes rain, will be lessened.