Hi Xswalden,
Thanks for editing your post to let us know what you learned.* I know of Saltcedar and he's good at id.* Hope you gave him a bit 'thanks'.* :)* I agree they are all trash trees, with the possible exception of the elm.
To id your elm you might want to post a picture of it at the UBC Botanical Gardens forum where several botanists hang out.* They are quite good at that type of id.* Here's their main forums page and the second link is where you should post it.* Do add your location in your profile so they won't have to ask and let them know where the tree grows.
http://www.ubcbotanicalgarden.org/fo...ffb27b3a8f929&
http://www.ubcbotanicalgarden.org/fo...0674f8285&f=38
I'd love to know what you find out.
Newt
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.