Level Design for Computer Games - Foliage Creation and importing into Unreal

As a requirement of this unit, to add both some set dressing and some life to my level, I have implemented some foliage, this is currently only in the form of trees currently, which are also bare of leaves due to my surrounding.
This was a thematic design decision I made to keep the trees simply restricted to a trunk and branches, as being based in a post apocalyptic desert type setting, no leaves would remain on the trees, the trees would in fact possibly not survive themselves dependent on the conditions of the apocalypse.

For this part of the level design process, I have used an external software in order to create trees without leaves, leaving only the bare trunk and branches, I took a Joshua tree and an Elm tree and placed them scarcely, with a couple of small groups at the entrance to my town.
I placed them scarcely for the same reasons as I took away the leaves as I feel if the trees were too common it would take away from the apocalyptic feel.
I varied the sizes of the trees slightly within groups to give effect that they are not in fact the same mesh, and at the same time used multiple different types of bark texture to give a different visual effect.

The trees I have imported into my level can be seen below;

I will be looking to implement some form of weeds, in dead patches, saturated of most colour with a colour value allocated appropriately for the theme, though this is currently in progress.