Unwrapping tree and it's leaves

Is there a way to unwrap the tree and the leaves?

When I imported the model to UE4 even after putting the leaves as a square UV it didn’t look like I wanted to, was completely streched.

Maybe anyone knows how to solve this or knows a good tutorial?

Please supply always a blend file and pictures illustrating your problem, and any other piece of information…

For example, where did you get the tree (did you modeled it, are the leaves particles, did you used sapling or any other tree generator?)
Also show us the textures you are using, and the result from UE.

You’ll get a faster and better answer if we know exactly what the problem is… right now, we only know the textures are streched… not even we know in wich direction is the streching happening.

It won’t let me upload the blend file so here are some screenshots.
It’s just a simple tree I made with sapling and the leaves are not particles.
On the left is the model, top right is texture (it’s a .tga) and bottom right is UE4 result.

Left is leaves unwrap (stacked on one another) and right is trunk and branches.

Your screenies don’t show any obvious stretching to me, though the unwrap for the tree looks as if it might be problematical depending on the image texture used. In the UE4 view I see no trace of the actual image used, and it is obviously not using the .tga file’s alpha channel, hence the square leaf shapes. It’s hard to tell because of perspective if the squares are stretched into rectangles, but if so, make sure you Apply Scale in Blender to the base leaf mesh being used for the leaf generation, and perhaps use Apply Modifers in the export options (if it exists). Same for the tree mesh if it is also “stretching.”

That is because Blender doesn’t unwrap trees correctly, at least for the bark.
The solution is first, put a seam on every branches, and unwrap, then in the UV editor take each branch, make it look like a rectangle and resize it to match your texture.
I know that it’s a tedious and time-consuming task, but it gives awesome results.