For the wet soils area, persimmons and pears with Pyrus communis rootstock are considered acceptable. Is there any possibility of doing hugel beds where the trees are going to be planted, maybe even mound the planting site to give the roots more area above the water line? Remember, when planting a tree that doesn't like wet feet in a wet area, it's always easier to plant above the water than to figure out a way to keep the water out of a hole that you dig. The hugel bed would help to regulate the moisture levels, also.
As far as the spruce area, while there are some studies that show that spruce needles as a mulch can reduce germination rates, it seems to be plant specific. I personally feel that this probably has more to do with greatly increased acidity of the soil than an allelopathic compound released by the spruce tree. Have you done any soil tests of the area? If the tree is gone, you could get decent results from throwing a little lime around the area for a quick pH adjustment, then incorporate lots of good
compost into the area which will help to maintain positive pH levels while the plants grow.
From
http://www.edibleforestnursery.com/SOILINFO.HTM :
pH: Alkaline soil (over 7.5 pH) makes iron less available causing the leaves to yellow. Pome and stone fruits do fine in most acidic soils (down to a pH of about 5.0 or a little less) but acid soils make some minerals less available (calcium, phosphorus, and magnesium) and others overly available (such as aluminum and manganese) So if your soil is over 7.5 add an acidifier such as sulfur or an acidic mulch. If it is very acid, add lime. See your extension agent for amounts.
Hope some of that might help you.
"Instead of Pay It Forward I prefer Plant It Forward" ~Howard Story / "God has cared for these trees, saved them from drought, disease, avalanches, and a thousand tempests and floods. But he cannot save them from fools." ~John Muir
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