The link is not working (for me anyway)

I'm not sure what I did wrong with the link. It works if I click on it from a computer that has already been there once. But if I click it from a computer that has never been to it before, it doesn't work.

Anyway, I'll try a link to the page containing it (rather than the photo itself). It's the first photo on this page. If you click on the photo you will get a larger image.

Here is a link that might be useful: Large tree with yellow flowers

It's pretty hard to tell. Some trees with yellow flowers that grow well in our low desert are:
Yellow Oleander (Thevetia peruviana)
Mexican Bird of Paradise (Caesalpinia mexicana)
Golden Shower Tree (Cassia fistula)
Tipu (Tipuana tipu)

More choices can be found at the link below.

Here is a link that might be useful: Landscape Plants for the Arizona Desert

Thanks aztreelvr. Yes, it is hard to tell from that photo. It's interesting how the flowers appear to be in clumps, as opposed to spread evenly around the whole tree.

Thanks for the suggestions and the helpful link. That Cassia fistula is beautiful! I'll look into that one.

I forgot to include the Cascalote (Caesalpinia cacalaco) on the list. It blooms from October through February with spikes of yellow flowers. The blooms are slightly fragrant and attract hummingbirds. Some trees have thorns and a new cultivar from Mountain States Wholesale Nursery is thornless.

Here is a link that might be useful: Cascalote

The Cascalote is very nice. I just sent an email to Mountain States requesting the name of a retail nursery that may have one. Thanks!

aztreelvr - Unfortunately, Mountain States tells me they're sold out of the Cascalote and will not be able to supply any for quite a while. Have you seen any at any nurseries lately?

By the leaves and the flower groups, I would guess Tecoma stans (yellowbells) -- which, surprisingly grows really well here.

Thanks kmvanatten. I didn't know yellowbells got that large. I'll look into them.

I'm just guessing but I think it's a Cassia but definitely not a Cassia Fistula which has cascading, wisteria like blossoms. (I think if you sent the pic to L.A. County Arboretum, they would give you a definite answer because I believe they have some.) If you ever find a source for a cassia fistula, (not the seeds), I would be interested. Thanks,
mkfairchild

Sure, could be Cassia leptophylla.. Hadn't thought of that...

Looks like a Lucky Nut to me, or sometimes referred to as a yellow oleander. I currently have one in my backyard that I recently planted, but its only about 4' high atm.