It looks like the pines were planted as they are in straight lines. It is difficult to grow much under the shade of conifers.

The idea of the pine plantations, when they were first planted was to rebuild forest and pines are great first trees and nursery trees for hardwoods. The pines should be thinned out every ten years, either taking out every other row or every other tree. That opens up space and light for hardwood seedlings or you can plant hardwoods like black cherry, walnut, oak, maple, beech -- what ever the normal succession forest type in your area would be.

Eventually, after several decades you should have a nice hardwood or mixed wood forest.

Check with your county or state for advice about culling the pines and managing your woodlot. Many places have tax incentives for those who practice good stewardship of their woods. If you remove pine and spruce and let deciduous hardwoods grow up, you will find it much easier to create a woodland garden.

Here is a link that might be useful: Ontario Woodlot Owners

Cara,

If you decide to keep the pines and spruces, I'd consider transferring some of your baby pines & spruces to your woods. Sprinkle them among the older trees. The plants are engineered to grow under these conditions. I know white pine for sure likes to be shaded when young. Doing this would make your mass stand of same-age trees look a little more natural.

Some plants that I've had great luck growing under mature pines:
feverfew
catnip
bedstraw
phlox
columbine
baneberry (doll's eyes)
foxglove
juniper (believe it or not, my common juniper doesn't need but about an hour of direct sun to live)
boxwood
barberry shrubs

I'd also check out some nearby public trails with some plant ID guides in tow. What grows in the heavy pine woods in your area?

I'd also consider gathering some of that fallen brush and making a brushpile (or several) for the rabbits and birds. There's some good websites with tips on building one that will be a good shelter for them and will add more life to the forest.

Good luck, it looks like you are well on your way to making a very nice trail on your land.
Laura

First of all, they aren't called "Pine barrens" for nothing. There are very few plants that will grow underneath a fully matured canopy of pine or spruce. I also would recommend thinning the trees out.
However, there are many plants that will grow in acid soil under pines where they get some light.

Some plants that might even work in the shade are:
Epigaea repens, Trailing Arbutus, Mayflower (damp)
Chimaphila maculata, Striped Wintergreen
Mitchella repens, Partridgeberry
Polystichum acrosticoides, Christmas fern (seems to thrive anywhere)
Cypripedium acaule, Pink Ladyslipper
Goodyera pubescens
(If it's cool and somewhat damp:) Linnaea borealis, Twinflower
Trientalis borealis, Starflower
Medeola virginiana, Indian Cucumber-root
Podophylum peltatum, Mayapple (again, damp)

Where trilliums will grow, most of these plants will grow. I suspect that the partridgeberry and the Christmas fern will grow in even deeper shade.