Hemlocks are the state tree for PA and 10' is hardly a speed bump here. In the ridge and valley region of the state (the main portion of the Allegheny Mountains) they grow regularly to about 3/4 of the way up the slopes and sometimes even on the ridge tops. They also need less moisture when shaded. I don't think you have much to worry about as far as roots rotting in the wet areas, but the trees may develope a shallow root system and be prone to being wind thrown. Hemlocks grow right up to the banks of streams here too. Hemlock grows over a wide variety of conditions, but does better in the right conditions.
Black spruce is native to your location and also to the wetland conditions at your site. It may be a better choice for the location.
My experience and interests are mostly with species native to the northeast quarter of the US, so I'll leave the other trees you mentioned for others to comment on. I hope the info helps.

Ziggy

Zigs given you what you need. I agree that going just by what info we have, hemlock should be fine (for both situations). Yews are notoriously unhappy with poor drainage.

I'd go with the hemlock. If you want variety, a white pine might handle the higher spot. As pines go, they have some shade tolerance.

+oM

ziggy, thanks for the very thorough response.

The thing that was confusing me was that my local nursery's web site, a "Native trees of SE Michigan" pamphlet, and a Midwest landscaping book all say the Canadian hemlock requires moist, well-drained soil. So my "speed bump" hill of sandy soil is only moist if it rains, and 10' down where the water table is. And the wetlands isn't "well-drained". I also had the landscape guy who was out to discuss our boulder retaining wall tell me hemlocks are hard to grow here, although they certainly sell them in every nursery I've been to.

My "Native trees of SE MI" hemlock info also says, it "needs moist or wet acidic soils...is rare in SE Mi...is very sensitive to hot, dry conditions so be sure to plant this tree only in cool, moist locations." But maybe your "needs less moisture when shaded" comment is what makes the difference.

Also, the nursery site says it needs to be planted in a winter protected area, which the "hill" isn't. A couple of years ago after hearing an arborist speak, I asked him about which tree to use here and mentioned that I didn't think a hemlock would work since it needed to be winter protected (I'd looked at the nursery info then, also). He looked at me like I was nuts, and said, "They're grown in Canada!"

I'd read about the black spruce in my "Trees of Michigan and the Upper Great Lakes" book. Thanks for the suggestion, but I'd ruled this tree out because it said it "has a shallow root system that in swamps and bogs is easily uprooted by strong winds" and "the lower branches persist for many years after dying, making the tree unattractive for ornamental use." And there's a picture showing an unattractive black spruce with the dead branches half way up.

So, based on what you both say, I'm wondering if the higher altitude in PA and the more northern WI location make a critical difference in the temperature factor. Hemlock is native to Michigan, but apparently in the northern part.

I'm not trying to be difficult here. It's just that I spent 30 years in a condo with very little garden space, where I only could plant a few bushes and perennials. Now I have over an acre with lots of possibilities, but I have no experience with trees, and don't want to goof on these expensive plantings! So I'm trying to understand what my margin of safety is on these trees before I buy any!

If, based on what I've added here, you think I'd still be reasonably safe with the hemlock, then I'll go ahead with them, since perhaps the amount of shade may end up being a bigger problem, which is why I am considering the yews for the hill if I don't use the hemlock. It sounds like the most logical place to try the hemlock would be the E location near the wetlands. The other wetlands location gets the W sun and winter winds.

Thank you so much for your input! Anne

You should not forget about the wooly adelgid, which is killing hemlocks across the eastern states. If it is not in your area, it may well be there soon. In Western MD the forest service is warning all landowners in forstry programs to expect their hemlocks to die. They are all gone in the Shenandoah National Park (magnificent stands!), and in my hometown of Westfield, NJ the only surviving hemlocks must be sprayed every year. There have been some limited experiments with the release of imported predator beetle species, but I have heard nothing yet to indicate any but the most limited success with this approach. Until I hear differently, I expect the hemlocks to go the way of the American chestnut, etc.

I know some people are reluctant to plant non-native trees, but with so many of our native trees threatened or being killed by foreign bugs and/or diseases, I think this porhibition against non-native trees is really backward and silly. So, with that rant out of the way, why not consider Norway spruce?

--Spruce

Conifers, and all trees for that matter, will have the bottom branches die back if shaded enough. Shade tolerance varies a lot, but it happens to them all. The persistance of the lower limbs that die varies widely depending on the strength of the wood, the weight of the branches, the amount of wind reaching the tree, animal activity, etc... Dead branches come off with saws and shears though.
Most plants can not live in wet soil due to lack of oxygen. Non wetland adapted plants will keep their roots above the water table. Wetland adapted plants are able to get oxygen in other ways, and may send roots below the water table. Conifers tend to all be shallow rooted compared to some of the tap root producing hardwoods like oaks. The combination of shallow roots and wet soil makes any tree prone to being uprooted by the wind. Based on your description of the site and the wet land adaptation of black spuce, I think it will root as deep or deeper than your other options.
There are no guarantees in gardening or forestry or any related field. All any of us can give you is our best educated guess based on our knowledge and experience, and the information provided to us. Even using a "professional" who privides a financial guarantee,it is still just an educated guess. Even making the best possible choice to accomplish what you want on your site doesn't mean the choice will be problem free. Hemlocks and black spruce are at the cheap end of the scale as far as planting trees go. Being that planting any tree has risks, these trees are probably the safest bets financially. I still feel my original comments fit the situation the best.

Ziggy

After reading your further comments this morning, I spent 5 hours wandering through the nursery that supplies many of the landscape companies around here. Seeing trees (up to 12' tall) and shrubs at many different stages of growth, clarified things for me.

WItom, there's a small pine that was "planted" on our site by some sort of wildlife (I assume, since there's a spruce almost on top of it), and it doesn't seem to fit the setting since there are no other pines anywhere in sight. The only other evergreens on site are 3 sort of scrubby looking smallish cedars hanging over the water at the back of the lot.

spruceman, the Norway spruce is too large for the locations. I was aware of the wooly adelgid, but your caution has helped me decide to try only one hemlock. I'll use it in the protected low spot.

ziggy, thanks for the further useful information, since I really know very little about the tree world. Neither of the nurseries I've been to have black spruce, so the hemlock seems like the best choice for the one area, and I'll try white spruces for the more weather exposed spots which also get some western sun. There are also a couple of places up near the front of the lot where I had already thought spruces might be good with full sun. I'm trying to keep most of the wooded lot looking natural, so having the spruces somewhat scattered around should be attractive.

I didn't like the way the "pine" cones pulled down the top branches of the "Densata" (Black Hills) variety, so I'm hoping that will not happen with the picea glauca that I'm choosing. These white spruces seemed to have their cones nestling in closer to the inner part of the branches so they don't fall over. Please let me know if this is not correct!

I saw the concolor fir for the first time, which on paper had been a possibility. I didn't care for it at all, since it looked fake to me. I also walked past some Vandeerwolf pines, which I'd never seen before, and that also looked fake.

Thanks once again for helping me arrive at a decision on this.

Anne