I've a different suggestion, though the value of what I say has to be considered against the fact that I've never even played an RPG, and have only ever drawn one battle map intending to draw it (However I have had another three building maps mistaken for battle maps, and the one battle map I did draw deliberately won second prize in a Profantasy Forum battle map competition - the Henge Portal map I recently put up in finished maps)
The colours are good, but there isn't a lot of ground for the players to 'be', if you see what I mean. I've not seen a battle map so covered in tree stuff.
Assuming that you shrink the trees a bit to leave space for players to move around, you might be able to improve their umbrella appearance by adding more texture within the shape of each tree, and reducing the 'burnt edges' appearance. Most trees I've seen on the more striking battle maps there are around the place are far more irregular in shape, and frequently have holes in them that go right down to the ground.
Its really difficult trying to explain what I mean in just words, so you will have to forgive me for sticking a picture in here to show you what I mean.
This is a 1/4 size tree from a set of spring trees I'm working on for my Merelan City map. The resolution is very poor, but that's because I'm nearly out of broadband allowance for the next 5 days (thanks to yet another mammoth Win 10 update!), and this is only an example. What this means is that you can't see the individual leaves, and the transparency around the edges is definitely a bit rubbishy!
Attachment 88566
EDIT: Please also appreciate that this is a spring tree, and only has about half the foliage on it that the summer version will have (when I make it), so the appearance couldn't be more towards the other end of the scale from your own leafy trees if I tried, unless I showed you one of the winter trees!