Tree identification

Hi There
Could you please identify this tree. I moved in last winter so I don't know if it was healthy last summer but within the last 2 weeks the leaves have turned brown. The trunk is about 4 to 5 feet high with this big huge bulb for lack of a better word at the top of the trunk. I thought it was called an umbrella tree but I know now that it isn't.
Thank you

 

Weeping Wych Elm Ulmus glabra 'Camperdownii'.

Not sure what the problem is, maybe a fungal disease, though not Dutch Elm Disease.

 

Its a very old Ulmus glabra 'Camperdownii' . I am not sure what is wrong with it . Is it planted in the ground >?

 

Hard to tell from the picture but it looks like it could be planted too deep

 

If the octagonal enclosure in which the tree lives is, in effect, a large planter---perhaps the tree's roots are constricted.

And what is up with the 'bulb' at the top of the trunk? Is this the result of being pollarded, or what?

 

Thank you to all for your replies. Now that I know what kind of tree it is I can deal with the problem at hand.
Again thanks

 

The pest issue on the leaves is Elm Leaf Miner:

http://oregonstate.edu/dept/nurspest/elm_leafminer.htm