The pack of trees (similar to olive or willow trees) is made in the program Speedtree on the basis of scanned tree trunk with textures in high resolution, as well as were scanned bark and a set of leaves of this tree for subsequent creation of texture atlases. There are 20 trees of different variations (and 16 unique meshes) based on one scanned tree trunk: variants with green and yellow leaves, with fallen leaves and without leaves. Just choose the variant you want and put it in your scene, each tree is fully ready to use in engine versions 4.25 and above. The "WindDirectionalSource" placed in the scene gives good results, but you can implement your own wind variants. Also in the "SpeedTree" node, which is in each master material, there are settings for the quality of the wind and lodes. 

In the settings of the material there are changes in the shade of the leaves and the color of the subsurface.

Demo video here

IMPORTANT!!! MUST-READ!!! UV sweep branches are the result generated by the program Speedtree, where there are multiple overlapping UV islands, but on the quality of the display textures does not affect and when building the scene or lighting engine does not give any error!

Despite the impressive number of triangles in the grids of some trees assets are well enough optimized for such visual quality. Also, by adjusting the display of LODs for your purposes, you can achieve more optimization.