Cornus alternifolia is one I'd look into for your first choice. Great tree!

Try 'Forest Pansy' Redbud - try to get one of the grafted/rooted ones, not a seedling, as the "true" 'FP' holds its leaf color better in summer - the seedlings sort of green-out. It also means a higher price tag, but....

I don't know if 'Bloodgood' Japanese maple is hardy for you, but it's another thought, as is a paper-bark maple or a trident maple.

I would concur with the C. alternafolia, or a C. kousa or hybrid thereof.

How about one of the disease-resistant, reddish/purple leaved crabapples - you could also select for red, larger fruits, that are held over the winter?

It may be taller than wanted, but a birch, esp. one of the white barked ones (try 'Heritage' river birch, or 'Duraheat') can be very good looking in winter - no flowers, of course.

any redbud .. no need for the expensive one.. if there is a budget ....

ken

Depending on how much sun you have, the 'Forest Pansy' may not have that purple-ish color on the leaves. Mine are just barely getting enough sun and they are almost green by the end of the year (although they start out with great color in the spring).

Thank all of you for the advice so far - I am in the process of looking up into all these ideas/info and will post again. I am also curious about what will I find in the nurseries here once I narrow my list down

Finally, I know that I am asking for a lot: one tree with 4 season interest and and one evergreen, both without much light. In the end I might have to give up on some trait or another, but hopefully I will arrive at a better choice with all your help.

Thanks again.

The above-mentioned Forest Pansy, Paperbark Maple (Acer griseum), I'd add Heptacodium miconoides (Seven Son's Flower) although technically a shrub, would work well, and Stewartia pseudocamellia, although it would eventually not be a small tree...

For the evergreen, look into Sciadopitys verticillata, Japanese Umbrella Pine. I have one growing very nicely in a shady position.

The soil has a good amount of clay, but I will improve it when planting.
It may be best to find a tree that does tolerate some poor soil. Amending soil at planting is temporay at best. What happens when the tree roots grow beyond the amended planting hole. The Amelanchier likes moist soil, which is what happens when you have clay. Many conifers, Sciadopitys, and Picea orientalis, like to have well drained soil. Also Japanese maples likes well drained soil too.
Go to you local nursery and look at redbud. They seem to grow well in PA along wooded tree lines, so they will tolerate some shade, there are many new cultivars, from a weeping variety to one with red leaves.
I always recommend that you also shop at a nursey or garden center, who employee people that have some knowledge of the plants they sell.
LOL Mike

Hophornbeam (ostrya virginiana) also grows well in part shade.

Ostrya is a dandy native tree. The similar Blue Beech (Carpinus Caroliniana) is another choice native understory tree. Plus, it can have knockout fall color. Viburnum prunifolium and V. lentago also make nice small trees that can handle some shade.

I have found that variegated plants look nice in that type of situation. The following variegated plants would look great:Cornus Kousa 'Wolfeyes', Cornus Alternifolia 'Golden Shadows', Cornus Mas 'Variagata', Zelkova Serrata 'Goshiki', Fagus sylvatica 'Tricolor'.

For non variegated plants Stewartia Koreana and Acer Griseum can't be beat for 4 season interest.

For evergreen plants american holly (Ilex Opaca) is nice and has red berries if you get e female form but it is slow, Picea orientalis is a great plant. I have one growing in high shade with a few hours of direct sunlight in the summer and it had done well. Canadian hemlock and Chameacyparis Nootkatensis should also do well.

One other option would be Southern Magnolia. Brackens Brown Beauty or Poconos should do well. If your in zone 6B you may also look into a southern Magnolia Cultivar called 'Kay Parris' Several Magnolia experts are calling it the nice cultivar available.

David