Hey, it's detective fiction. One of the purposes of great detective fiction is to make you grin. That sentence is a very good example of the kinds of sentences that are supposed to make you grin. Instead of manipulating your emotions with grisly descriptions, the detective writer introduces the grisly, but with a comic twist. This sentence not only gives you the disembodied arm, which is detective writer humor through word choice, but also gives the pecan tree, which is detective writer humorous use of supplied detail. When I read the sentence cold, I immediately thought, "Oh, here's a detective story writer."
I did check out several dictionaries, being a good little AWADer, and disembodied, as shown in Bingley's quote, works. There are several dictionaries that showed that disembodied could simply mean unattached from the body--not a use I've heard before, but, hey, it's there--even in Cambridge. That's why tsuwm wrote that he didn't find the use strange. tsuwm knows these things. He's just got to develop his ear for hearing detective story detail, especially when humorously used, as in the 'pecan tree.'
