I would like to encourage you and offer some points where appropriate however I must first ask you this:
Are you creating these images in order to use them in Wesnoth (perhaps the background for the story part of a campaign?) or just for fun?
I have done many random things for fun and posted them on the forum so believe me when I tell you that people complain about it.
For myself I don't have any problem with you posting random art here at all but for some reason others will
Ok, so now going for some points I could make - I am treating these images as the beginnings of something you are making for a campaign, if this is not what you are doing then some of the things I have to say might not work.
I like the haziness and your use of colour however I don't know about the birds in your first picture. They seem a little too simply drawn.
Here I am making an image based on yours without the birds at all.
And here I have redone the birds trying to keep it close to your original style. I am not saying that my versions are any better, as you can see, I tried to keep it as close as possible to yours, but I'm offering some different ideas so you can see how things might work if you looked at them another way.
Regarding your tree: I'm not going to post images of this, but I would suggest that you consider working with the shading differently, remember that a tree is a 3D object and so branches\leaves will be in front or behind each other and the trunk will be round.
Keep drawing and if you want to keep up that hazy style (it might suit some campaign stories) you have my support but I suggest you work on your technical execution of the images while developing your unique style.
Look at Picasso's earlier (rose period) paintings and then his later ones. I don't personally like his art but nobody can say “he did it like that because he didn't know how to paint”.
Work on technical exercises, take a photograph of something and put it on a different transparent layer then paint it as an image in your own style, pay attention to light and shadow. It might seem boring or pointless but after practising with these uncreative technical exercises for only a short while, you will be surprised at how much better you are able to express yourself.