Well, there are 8 identical trees in that render. 2 have a water texture, the other 6 have the cloud texture. And even just one tree makes render time sky rocket. But as fas as I know, you can't make splashes in the foreground without adding a ton of render time anyway. But is render time what's important, or is it the finished render? I guess that depends on the artist and the scene. For me, I don't care if it takes a month to render, I just care about my finished image.