Nah. They keep my frames from dipping too low (and these ones by Toxa_Batoxa are seasonal to boot). I've used mcguirel's M:URST SpeedTrees in the past, but i like the look of these billboards more. Also, considering my processor is kinda subpar, i'd rather sacrifice a tiny bit of detail for better framerates, even more so because of all the grass splines and objects i used. Personally, i've found they mesh really well with the greater amount of detail one can put into a model railroad as compared to a full-scale route.
I used to use Pofig's SpeedTrees in TS12, but since some bright spark at N3V decided the thousands of SpeedTrees made before T:ANE weren't good enough for their "flashy" "new" simulator, i can't use them now. His were the best SpeedTrees around, no doubt. Sucks that every time i want to use a TS12 route in T:ANE< i gotta replace the SpeedTrees, but that's a topic for a different thread.
Thanks for the suggestion though.