Trees

Can somebody please explain to me why my trees have stopped growing. If I click on them I get a megaphone, a video and another. I clicked on the video and my tree disappeared.  So after rebuying them j clucked on the megaphone but just got a sign on front of them.

Trees only last a certain amount of time. The video lets you watch a video to remove them. The megaphone notifies community members that you need help on your farm. They earn coins when they water your trees, and you earn them if you water another member's trees and the tree's life extends. Axes cut down trees; saws cut bushes; shovels remove dead strawberries or honeysuckle (for bees).