Looks good. As chrisradsby said, your alpha is not rendering correctly. I am not familiar with blender but dig around to figure out whats going on there. The actual map looks fine.
Compare the trunks to the one you have currently. It looks like you slapped a rock texture on the trunk. A little bit of tinkering and this would be a great first tree.
Thank you for the comments and to Sasochicken: Yes I actually made the lighting blue to give it a "colder" night touch since it just looks so much better that way but that's just for this render anyway I understand that the alpha isn't working properly I actually tried quite a lot to see what's wrong so I'll look around and see what's causing it. And I also agree about the trunk texture it's actually a real tropical tree photo that I got off cgtextures but it doesn't seem to look too good.
Okay fixed the alpha problem I hope it seems I wasn't using the right settings in blender. Hopefully it will work in UDK. Couldn't get a texture that looked good on the tree trunk I tried arranging the UV unwrap but still has a bit quite a bit of stretching.
Excellent start. I would make one minor tweak. Take your leaves you used, and rotate them slightly so they all face forward a bit. Instead of extending straight out. (Looks like you started doing that towards the end)
Also, on each side, you can offset them ever so slightly so they are not growing out of the same exact spot.
Google "Palm Leaves" and you'll see what I am referring to.
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As for the trunk of your tree; see here.
Compare the trunks to the one you have currently. It looks like you slapped a rock texture on the trunk. A little bit of tinkering and this would be a great first tree.
Keep at it.
Also, on each side, you can offset them ever so slightly so they are not growing out of the same exact spot.
Google "Palm Leaves" and you'll see what I am referring to.
Keep it going!