How about a picture?

I'm also computer-picture challenged...don't know how to do that. But if it's any help, the crown looks like a small fleur-de-lis symbol...well, sort of. More like a crown with a stem.

Golden Rain Tree?

Here is a link that might be useful: Pictures

This post was edited by DeClercq on Mon, Jun 23, 14 at 19:44

@DeClercq

The photo link you provided is of the Golden Chain Tree, not the Golden Rain Tree. I agree though, likely Golden Rain Tree.

How did a tree native to eastern Asia get on my block? No, looking at the pictures, that's not it. It looks like a regular oak like on any American street. And BTW, I didn't mention that last year, black bumblebees tried to feast on these crowns, and we had a load of dead bumblebees to clear away after a few days.

Are they lindens? If so, these fragrant flowers are beloved of bees, so I am not sure why they caused so many bumblebees to die?

Tulip tree? Are they blooming yet? Liriodendron Tulipfera, a Magnolia relative. Probably not it, but my best guess.

ispahan may be correct - there are reports that silver linden flowers are toxic to some types of bees, though I've never observed this myself.

Its not the Lindens that are toxic, its the insecticide imidicloprid that has killed bees by way of flowers on treated trees.

Dirr (Manual of Woody Landscape Plants) says,
âÂÂConsiderable German literature that points to honeybee and bumblebee death after sampling the nectar of T tomentosa, T petiolaris, T dasystyla, T x euchlora and others. One paper recommended that T cordata, T platyphyllos, and T x europaea be no longer utilized in urban areas in Germany.âÂÂ

Sounds exactly like a linden. Tilia cordata is very appealing to bees and generally considered safe. Tree in question could be Tilia tomentosa or silverleaf linden (lime), which is quite toxic to bumblebees but supposed nontoxic to honeybees.

As to how a tree from eastern Asia might get on your block is that it was intentionally planted :-)) Same as a tree native to the Balkans or Turkey got there. Trees with origins from far distant locations are not at all unusual in American gardens.

Here is a link that might be useful: flower images of Tilia tomentosa

Hmmm....getting closer, I guess. Looking at picture number 3 of 7 on this site:
http://reclaimbeauty.blogspot.com/2013/07/the-linden-tree-flower-and-its-fragrance.html
The yellow 'flowers' on mine are a bit smaller and more tightly packed, meaning each crown doesn't have spread yellow buds, but is more stiff and together. And there are a lot more green leaves, with clusters of flowers hanging only upside down, looking like dining room lights (yellow bulbs surrounded by green facing down on a table.) . Very thick trunk on mine, and I only see bees near the clusters which already fell off. And they seem to fall off almost all at one (like within a week).