thanks for the replies.. the tree bears no fruit -- just flowers. well, no fruit that i know of...perhaps very small berry type if any at all? birds do seem to like the tree photo of tree is in link below. Here is a link that might be useful:

garden 2006, if you want a 'Cleveland' pear, plant it in a sheltered place where it has room to spread, and also can get the sun it needs. Of course, that kind of planting place is not easily found in a residential situation. At least you are not wanting to plant a 'Bradford' pear tree. In our area the Bradford pears start displaying limb failure at around 9-10 years. Local landscapers, suggest the Cleveland and the Aristocrat cultivars as a better option, for those people who have their heart set on having a flowering pear. The Cleveland pears spread quite wide canopies, but in our area do seem to hold up much better than the Bradfords. Our locally grown Aristocrat pears hold up even better than the Clevelands. They also are not such hogs for canopy space. I am not sure if the same is true for all the callery pears, but the Bradford pears do emit an almost rotting corpse odor when they are in full bloom. One usually only smells that odor if they are walking past or under one or a row of them in full bloom. Another good thing about the soft wood ornamental pears to consider, is that the size they are once they begin breaking and need to be removed make them less dangerous and expensive to remove. I certainly prefer that over the expense and injury risk of removing some of the dangerous, massive, grown soft wood maples; along with old, hard but brittle wood, Cottonwood trees.

The White Dove Tree, Davidia involucrata, might fit the bill - hardy in your zone, matures at about 50 feet, moderate growth rate. I'd love to have one, tried a couple of times but they just didn't make the winters here, despite the fact that I've seen them a few times at local nurseries.

If this is the pdf you meant, I posted it. If that's the one, I'm glad it was helpful. Since they put the "never plant this tree" symbol next to the quaking aspen, I don't think they're worried about recommending against popular trees. There's almost always a trade off with fast growing trees. If it grows fast, it'll almost be assured of having weak wood. I'm in Farmington, and we get canyon winds (gusting over 100 mph), so I'd steer clear of a tree prone to breaking up, but in Salt Lake City, it's not such a big issue.