Hi,
I imported trees from TreeIt software but I don't have Alpha on the branches and leaves. I changed the files from png to tiff like the trees from sdk but it doen't work. I don't understand what I'm doing wrong.

Does your albedo / diffuse contain an Alpha channel with an Opacity mask in it? If not, why not?

yes diffuse have a alpha channel

Did you adjust the slider under Opacity in material editor?

AlphaTest ?

I tried everything and nothing work. In others softwares the alpha works fine. It's like CryEngine don't see the Alpha.

Well i can confirm alpha works. How does the opacity mask look like?

opacity mask is black and white.

I attached screenshots but they're not showing up.

Make sure if you are using Photoshop, to save the alpha as an Alpha Mask (In the color channels). Then save as using the CryTIF plugin.
The format requires the mask specifically in the Alpha Color channel.