I actually make an outdoor statue garden rather often, and usually around a huge pit. Usually based on the fact that my idiot dwarves need an excuse to go outside and start tantrum spirals because they got caught in the rain not develop cave adaptation, which would result in tantrum spirals when later forced to go outside.
I actually tend to dig down and collect a sum of stone as I simultaneously plan out my exterior walls (which will be made of said stone and usually enclose a large area.) and cut down as many trees outside that area as possible, dragging the logs inside before hostiles start showing up. That way I have a ton of wood to use, a defense setup, and an internal emergency supply of wood. I personally like forest settings myself, and at least some of the dwarves must enjoy it, but I'm no hippie either, and tend to lop down everything I don't specifically want. Ends up looking like a damn jungle outside the walls again by year three anyway. Animal pastures usually end up in the soil layers, just so I don't have to deal with building more walls to protect the livestock.
Usually after the initial logging I have enough wood to keep going for years, and then it's on to the caverns for the mushrooms. The caverns are usually so congested with shrooms by the second year that logging becomes a necessity just so they can be used for ANYTHING, and once all the cavern ground near the fort is clear-cut I don't really need anything besides some moderate tree farms or whatever survives being trampled by the animals.
The exception would be locales with little to no surface wood; then I'd end up walling off sections of the caverns as dedicated tree farms. They just grow so freaking fast in the caverns... Gotta be something in the soil. Ancient FB extracts? Probably just the lack of traffic.