good start compared to your previous mockup, but there are things that you could easily improve (and others that would be worth improvement although it won't be as simple)
The first one is the trees. You don't make a convincing impression of circular trunk atm, rather polygonal thing, as if the tree trunks were pencils. Even keeping the limited number of colours, you can better render cylindrical shape if all your stripes don't have equal width. Also, the highlight would work better if not being the last stripe.
<-- an illustrated explanation I received from Arachne
a while ago.
Then, you added transversal, darker stripes. They can be used to reinforce the cylindrical shape (by being curved) or organic feel like in NSMB and Mr. Nutz:
But by making them 45° parallel and straight, you actually reinforce the artificial feel of the trunk :-/
Also, I suggest you compare your bushes to the one in SMW
with as little colors as you have, they propose a clear shape illustration and volume suggestion (pyramidal, but organic and irregular)