From your photo, it looks like an ash tree, but it's not close enough to tell. Other possibility is a hickory maybe? Same with the disease issue. Too hard to tell from the photo. But, if it is an ash tree, it's probably Ash Anthracnose. It's warm and very wet in Chicago this year, right? Perfect conditions for this: "Ash anthracnose is probably the most common disease of green ash. It is caused by a fungus and occurs during cool, rainy weather. It can be confused with ash plant bug and herbicide damage. Individual trees vary in their susceptibility to anthracnose to the extent that some trees may be infected every year and others only rarely or never at all. Initial symptoms on green ash include very small (grain of sand-sized) purple or brown spots, sometimes with a cream-colored center, on young leaves. These spots may enlarge and coalesce forming brown blotches. Leaves often become distorted and drop and young shoots may be killed. Defoliation and leaf browning cause homeowners a great deal of concern, but treatment is generally not warranted. Affected trees usually put out a second flush of leaves and make up for lost time later in the growing season. However, trees that have been defoliated three to five years in a row might benefit from chlorothalonil, mancozeb or thiophanate treatment at budbreak to prevent infection. The fungus can overwinter on the ground in infected leaves and twigs, so raking and disposing infected material may help reduce infection the following spring." Your main link didn't work for me -- brought up a screen, but no photos, looks like you have to create an account to view them, and I didn't want to do that. Here is a link that might be useful: Pamphlet where I got the Ash Anthracnose info:

the seed are called gumballs ... and when the tree ages enough.. to start dropping them.. you will not be able to walk barefoot in your yard ... glorious PARK trees.. you better think long and hard about whether your yard is big enough ... also.. known for surface roots ... and suckers.. if you cut a root ... now.. if you just gotta have one.. check out the link ... who cares about all the other problems.. lol apparently i am a bit bipolar on my opinion of these trees.. lol ... oh.. and i forgot to mention.. the heavenly.. aroma of a crushed leaf. but it is very ephemeral.. lasting only seconds ... ken Here is a link that might be useful: pay real money for a variegated one ...

The second tree is sweetgum, not sure about the first. Sweetgum had spikey seed balls that some folks don't like. They breed/grow seedless varieties I think for landscape purposes. Sweetgum is stunning in the fall, but maybe not so much in CA.

Embo captures well - via the report he read from China - that these things will struggle to survive, and often look like it. I saw one somewhere between Scranton PA and Allentown, PA, a hard 6a location, a few years ago...that looked absolutely awful. But like a mangy old feral tomcat, it was surviving. I didn't have time to stop for a pic. So...back to Sarah's interest in the species if she ever shows up again... 1) have a sunny site with good, deep rich but well drained soil 2) not a dry microclimate (7b in "the south" could be way over in OK/TX, very prone to summer drought, or lower elevation parts of the NC or GA mountains with > 55 inches of rain a year!) 3) make sure roots aren't knotted when planting 4) anticipate a cutting grown cultivar could take years to form a leader (I am waiting on one myself) and EDIT - I forgot 5) keep it to one leader because generally speaking most trees look and perform better that way: https://www.houzz.com/discussions/4977109/we-agree-some-cutting-grown-trees-need-aggressive-waterspout-control