My daughter is looking for this book, published no later than 1990.
A child is moving and does not want to go. The front yard of the old house has a tree, and the child has friends. The family moves. The new house has a tree. The child makes new friends. One of the two trees may be an apple tree; the other is some other kind.
If it was a chapter book, you could try The Middle Moffat, by Eleanor Estes, especially the chapter “Best Friends.”
Or this one, more likely: I’m Moving, by Martha Whitmore Hickman.
My daughter says this may be it, and will try to locate a copy to let me know.