Which tree should I plant?

[Dig-it Landscaping]

I am stumped on what kind of tree to plat at a house where I am putting in a patio. The tree can't be any larger than 15' in dia. or 20' tall. The tree has to tolerate very moist soil. The area isn't drenched 24/7 but it remains moist most of the time. The tree will also only get part sun and part shade about 50/50 because it is in a corner between the house and the deck which are both 2 stories tall. I live in zone 5. I know my plant material pretty well but im just stumped on this one. Thankyou in advance for any help.

[FoxDen]

What about a Harry Lauder's Walking Stick tree?? I think they are in the Willow family and will tolerate moist soil. Also; they dont grow really big. They are the trees with the "corkscrew" branches.

[steveair]

How bout a nice multi-stemmed river birch. Will tolerate the moisture, in general stay within the spec'd size range, and should tolerate the shade.