Oh well - my low-end hardware is heavily affected by 3D models being something more complex than mere cubes. Yesterday we had more than 90 000 cubes at 60FPS. Now, with real trees I have to drop the amount to 216 to keep the FPS at 60. So, this just means that there is no single silver bullet to solve the optimization needs on my hardware. I'd guess I will need some version(s) of LOD; using a more simple version for models which aren't close to the camera. I think in my browser bookmarks I've saved a few possible ways to automatically generate simplified versions of a 3D models, but in case you happen to have, or happen to know of a handy tool to auto-generate simplified versions, please comment below! (I remember reading that this could be done just using standard Blender tools, but I haven't yet tried it. It might be that my brain capacity is already running low for today.)