For your game, I have some suggestions.
Interesting idea, but scrap it and start again. Okay, not completely scrap it, but it needs some work :D
(0) rebrand it as an edumacational - pitch it at kids - target the home school market
(1) The music seems kind of repetititve
(2) The music cancels the user's music which might have been playing in the background, don't do this
(3) The initial (easy) trees are way too big
(4) Tutorial with set tree (something like only 6 slots, and a predefined set of ornaments, and you walk the player through the process
(5) First row of first tree should have... I dunno, 6 or 10 slots, then add a row every row or two they go up the tree
(6) rapid early progress is good! Even an adult can lose interest if the first ones are too 'hard' (read as: take too long even if they are actually 'trivial' compared to later trees)
(7) work on the doco. Okay, I get the thing about English not being your first language, and I have tremendous respect for people who speak multiple languages, so my hat goes off to you sir. HOWEVER - when you target the educational market you want to be a bit more precise. Example: trees are not 'male', so do not refer to them as 'his' - e.g. his sub-trees.
(8) Straight out of the gate I think you gave up too easily. The average paid iPhone game makes about $2000, which means that most games make considerably less than that, probably $1000 or less. The average is skewed because you have a small handful of games (Angry Birds) that make enormous money.
So I think you need to reset your expectations. iPhone development is like the lottery, we all hear about the big winners, but most tickets are disappointing. On the other hand, if I paid $100 for a lotto ticket, and it only gave me back $10, that would seem like a bad deal, but if it gave me back $10 every week for the next 5 years I'd be a lot happier and go and buy a lot more of them. :D Rather than getting one massive royalty cheque that you can use to buy a house, lambo and Brazilian supermodel on day one, you need to think of it as a stream of income - or better yet, a tree! A tree that you need to tend and if you take good care of it it will slowly grow until it provides you shelter.
Hope you found these comments useful