We do thin sugar maples in areas as a way to promote more understory growth. But we do this in mass producing woodlands that are over run with sugar maples. The mass producing trees like oaks and hickories may fill out more, but they have a more open canopy than maples. you need to do alot of maple thinning and it may take a couple years to see any results.

And new maples will sprout in their places. Which you can keep removing. A periodic controlled burn can help new maples from sprouting, keep small maples from thriving and stimulates a native seed bank if it is still there.

You will need to keep an eye on garlic mustard and buckthorn. They tend to show up real fast when you open the canopy also.

I would imagine you would find spring ephemeral species appearing once there was more light. I live near Guelph and see this in woods that have been thinned. If they are nice maples, maybe you could sell them at the market, or at the horticultural sale at the Uni. in the spring

I have a maple woods area which I thinned. After reading several books on woodland gardening, I followed the advice to clear selected areas, rather than thinning all over. In this way, you can grow a more diverse range of plants, although everything will need to be shade tolerant to some extent, and the plants have more time to establish good roots before the maples roots move into the cleared area. I cleared a strip roughly 20 feet wide and 2 or 3 times as long and planted dogwoods, redbuds, hemlocks, serviceberries, oakleaf hydrangeas, mahonias, as well as shade perennials. It has only been 2 years (and only 1 year for some of the plants), but so far all is doing well.

Unless you go to the effort of actually "killing" the trees you cut down, then yes INDEEDY they will grow back and it's not pretty...spindly, bent, leaning toward whatever sun they can find and very poor quality trees will result. After you cut the trees down, kill them systemically within hours of cutting them. Your MNR or Conservation Authority or even an arborist can tell you what product will work the best for the species you are cutting down.

I live inside a maple woods farm woodlot (city subdivision) with a smattering of Black Cherry, American Beech, Alternate leaf dogwood etc. I'm about 1 hour to the west of you. Our woods is not great... 3rd growth sugarmaple forest so like yours, it is VERY tall (all maples are about 70' tall) and the canopy is very high and sparse. We have a contract in our subdivision that we can't touch the trees unless they become sick or die and even then we have to petition to the city to allow us to get a tree expert to come in and take the tree out. At any rate, being a 3rd growth forest we see a poorly developed layering of the woods. High canopy with nothing underneath. So I've been working on finding species that will thrive in the understory to hopefully build it up at different levels. It takes a lot of experimenting to see what works best but so far I've added 45 new species that are all thriving and only 2 or 3 things have not done well. My local MNR told me that restoring the understory is next to impossible but I wasn't willing to accept that and give up and so far things are going well. On the ground we've managed to keep masses of Blue Cohosh, Trout Lily, Red Trillium, White Trillium etc...these were all here when we moved in but are at risk because all the other neighbors in the subdivision have gone against the city contract and removed them all. If you are interested, here is what we have successfully added to the wooded aread of the backyard in 2 years:

Existing Native Trees, Shrubs and Plants

Sugar Maple
Black Cherry
American Beech
Pin Cherry
Alternate Leaf Dogwood
Highbush Cranberry
Blue Cohosh (+s)
White Trillium
Red Trillium
Jack-in-the-Pulpit

Removed Alien Invasives

Garlic Mustard
Oriental Bittersweet
(poison ivy also removed due to children and pets)

Native species added

Red Oak (1) Downy Serviceberry (3) Pumpkin Ash sapling (1) Eastern Redbud (2) Eastern Redbud seedlings (2)
Arrowwood Viburnum (3) Red Osier Dogwood (1) Red Osier Dogwood seedlings (6) American Hazelnut (1)
Nannyberry (1) Spicebush (9) Winterberry Bush (3) Silky Dogwood Bush (1) Silky Dogwood seedlings (6)
Blue Beech Sapling (1) BurOak (1) Bur Oak Sapling (1) Winged Sumac seedlings (3)
Spotted Jewelweed
White violet (2)
Purple violet (5)
Yellow violet (2)
Pale Corydalis (3)
Bloodroot (+ Âs)
Mayapple (+Âs)
Wild Ginger (3)
Bunchberry (3) - OctÂ04 did not survive winter
Bunchberry seeds - octÂ05
Blue Eyed Grass (3)
SolomonÂs Seal (6)
False SolomonÂs Seal (+Âs)
Canadian Columbine (2)
Baptisia Australis (1)
White Baneberry "DollÂs Eyes" (2)
White Baneberry "DollÂs Eyes" Seeds - octÂ05
Red Baneberry seeds - octÂ05
Lady Fern (3)
Christmas Fern (3)
Cinnamon Fern (3)
Male Fern (1)
Ostrich Fern (+Âs)
Wood Fern (1)
HartÂs Tongue Fern (2)
Maidenhair Fern (2)
Royal Fern (3)
Sensitive Fern (+Âs)
Crested Shield Fern (1)

Garlic Mustard and Oriental Bittersweet are 2 species that will take over an understory if they are allowed to take hold. If you are serious about working on your understory I would survey it first and make sure you don't have an invasion of any of the alien invasivies and get rid of those first if you do. Opening up the canopy will just throw those things into hyper-growth. Doing ground planting with native plants and shrubs will help prevent the areas from being taken over by the non-native, invasives.

I also agree with the poster who said removing clumps of sugar maples would be more beneficial than overall thinning. You will get the same benefit but in grander doses and it will be much easier to introduce new species in clearings than to try to get something to grow in an un-natural way (like I am). The MNR told me "that it's next to impossible because even the understory shrubs and trees need to be able to compete to a certain extent with the large/tall trees. To try to get them to do it after the fact is almost impossible." So if you clear small areas throughout your woods you will have clearings where you can add trees like Tulip Tree, Red or Bur Oak etc... along with shrubs and plants and the will be able to thrive with the prescribed amount of sun/shade mixture. Sun from above but shade when the sun is at an angle on the rest of the woods.

Call your local Conservation Authority office and ask about their re-forestation offers. My Conservation Authority and the London office work together to offer GREAT deals on native trees and shrubs to anyone with large tracts of land who wish to naturalize, reforest or create windbreaks. The trees are extremely inexpensive and well worth the effort to pick them up. I don't know what your office is but here's the page for my office so you can see the kinds of deals they have:

Thames River Conservation Authority

This page is the hardwoods section but you can also get fir trees and shrubs.

For really cheap seedlings you will want to look for native tree/shrub/plant services in your area or come down to LongPoint (actually Walsingham) to a place called "Acorus Restoration". Bare root seedlings are 2.00 each and they have almost all native species respective to southern Ontario. They do large government and private restoration projects but are also open to the public. I have purchased a grand majority of my plants, shrubs and trees from this place because even if they die, I'm only out a few bucks. Here is their website:

Acorus Restoration

Acorus Restoration is used to dealing in large volumes so even if you ordered a huge amount they should be able to accomodate you. Email replies by these folks are kinda unreliable sometimes and the whole place is very *WIERD* (I can tell you off-list about it if you like to email me about it). But the plants are good quality and seem to thrive just fine.

Good luck with your project and keep us updated on how it's going.

Barb
southern Ontario, CANADA zone 6a

Thanks Barb and others for the replies. I have bought trees from Acorus with mixed results. Some plants extremely small, and some mislabeled - aspen instead of Oak! Others are doing OK. Prices are good.

Barb, I plan to do the same as you, adding mostly plants and not so many shrubs in this area.