Thanks guys and sorry for being silent for a long time))
The scene runs at 40-50fps fullHD on VeryHigh settings. Textures are 1х4096, 1х2048, 1х1024, 2х512, 4х256 and some CE3 built-in textures (256) for sand and grass.
Some trees were made with speedtree, but the main sakura is a retextured CE3 built-in asset) Yep, shame on me, lazy ass))
Particles are custom, as well as their settings etc.
And I spent a lot of time tweaking the ToD settings, especially fog, cuz I was new to it, and...)
Any LODs were made, because it's just a portfolio piece, not a professional playable environment.
The ideas with volumetric clouds and cheating with aliasing are great - looking forward to use it in my next environment)
Thanks again guys ;)