The Toronto Tree Thread

[isaidso]

With the proliferation of downtown canyons, the worry is that these streets are destined to be treeless or with pitiful looking trees that struggle. Are there species/varieties that can prosper with indirect sunlight? Adelaide West, Richmond West, Wellington West, etc.

 

[egotrippin]

Just for clarity:

Red Maple: Acer rubrum

View attachment 432584
source: https://rockwoodforest.com/products/acer-rubrum

Sugar Maple: Acer saccharum

View attachment 432585
from: https://www.jardindion.com/produit/acer-saccharum/

Both beautiful trees, but Sugars are a bit 'warmer' in their tone.

Neither tree is particularly salt tolerant. They would do better setback from the road a bit.

Between the two, Sugar will do better in Toronto on average, I find Reds are just a bit fussier.

What's your thought on hybrids? The street tree outside of my house is (I am mostly certain) an Autumn Blaze, which is a rubrum & saccharum hybrid. It has done exceptionally well on the boulevard between the sidewalk and road, and is probably over 20' tall in only about 7 years. It seems to combine the best traits of red/sugar/silver maples- fast growing, urban pollution tolerant and stunning fall colour.

edit- I realize I'm sounding like a salesman for Autumn Blaze maples here lol

 

[Northern Light]

With the proliferation of downtown canyons, the worry is that these streets are destined to be treeless or with pitiful looking trees that struggle. Are there varieties that can prosper with indirect sunlight? Adelaide West, Richmond West, Wellington West, etc.

Only a few tree species are shade tolerant (but still require light); but many of those aren't overly salt tolerant.

Probably the best combo is Basswood; its shade tolerant and pretty tough. Unfortunately, the City has tended over the years to use a European invasive variety 'Little Leaf Linden' rather than the native.

Sugar Maple and Black Maple will also tolerate shade, but are not good with salt at all, the City almost never uses them as a street trees.

Same problem w/Beech.

Black Ash takes some shade, but because of Emerald Ash Borer would not be planted.

Eastern Hemlock takes shade; but is not a canopy tree, as a conifer, and also needs its soil on the damp side, so would have to be irrigated.

Yellow Birch is salt tolerant, and a fast grower, and will take shade, but again, needs soil damp, so irrigation a must.

 

[Northern Light]

What's your thought on hybrids? The street tree outside of my house is (I am mostly certain) an Autumn Blaze, which is a rubrum & saccharum hybrid. It has done exceptionally well on the boulevard between the sidewalk and road, and is probably over 20' tall in only about 7 years. It seems to combine the best traits of red/sugar/silver maples- fast growing, urban pollution tolerant and stunning fall colour.

edit- I realize I'm sounding like a salesman for Autumn Blaze maples here lol

Hybrids, or Cultivars as they tend to be called in the trade are interesting.

I have mixed views, because cultivars include different things, and have different impacts.

So, lets start w/the one you highlighted.

Autumn Blaze is a marketing name for an Acer Freeman. As you noted, Freemans are a cross between Red and Silver Maple, which essentially act like a Silver most of the year, but have red foliage in fall.
They have the durability of Silver, which does much better in urban environments than Reds, with a fall colour some find quite appealing.

Acer Freeman, in the sense of a red x silver hybrid is in fact a natural hybrid that occurs periodically in Ontario. In that sense it might be considered native, except, that in this case, this specific tree is the result of man-made efforts.

In general, I wouldn't be too unhappy w/that one..........but as as with all cultivars, there is one very compelling problem; they are genetic clones.
Acer Freemans all all genetically identical; which means, if any pest or disease comes along that affects one, it may well kill them all.

That's single most obvious downside of clones.

****

However, there are other issues; some cultivars are crosses between native and non-native plants or are entirely non-native. In either case, they can sometimes be invasive and severely impact our native forests.

Norway Maples and their assorted cultivars such as Crimson-King Maple (the one that turns purple from early summer) are a classic example of non-native, invasives.

But you also get into interesting questions, for instance, having introduced Dutch Elm disease many decades ago, and having had many Elms die off, there has been a constant search for disease-resistant specimens.

There are some pure native elms that appear to have high resistance and breeding efforts for those are ongoing.

But in the meantime, cultivar elms, typically crossing a Japanese Elm with a North American one are a popular route to finding a disease-resistant Elm.

For that reason, cultivars should really selected with great care.

 

[egotrippin]

Hybrids, or Cultivars as they tend to be called in the trade are interesting.

I have mixed views, because cultivars include different things, and have different impacts.

So, lets start w/the one you highlighted.

Autumn Blaze is a marketing name for an Acer Freeman. As you noted, Freemans are a cross between Red and Silver Maple, which essentially act like a Silver most of the year, but have red foliage in fall.
They have the durability of Silver, which does much better in urban environments than Reds, with a fall colour some find quite appealing.

Acer Freeman, in the sense of a red x silver hybrid is in fact a natural hybrid that occurs periodically in Ontario. In that sense it might be considered native, except, that in this case, this specific tree is the result of man-made efforts.

In general, I wouldn't be too unhappy w/that one..........but as as with all cultivars, there is one very compelling problem; they are genetic clones.
Acer Freemans all all genetically identical; which means, if any pest or disease comes along that affects one, it may well kill them all.

That's single most obvious downside of clones.

****

However, there are other issues; some cultivars are crosses between native and non-native plants or are entirely non-native. In either case, they can sometimes be invasive and severely impact our native forests.

Norway Maples and their assorted cultivars such as Crimson-King Maple (the one that turns purple from early summer) are a classic example of non-native, invasives.

But you also get into interesting questions, for instance, having introduced Dutch Elm disease many decades ago, and having had many Elms die off, there has been a constant search for disease-resistant specimens.

There are some pure native elms that appear to have high resistance and breeding efforts for those are ongoing.

But in the meantime, cultivar elms, typically crossing a Japanese Elm with a North American one are a popular route to finding a disease-resistant Elm.

For that reason, cultivars should really selected with great care.

Thanks for the all that info, very informative. It's funny you mention Crimson King Norways and Little Leaf Lindens, both were both heavily used in my neighbourhood when it was built ~40 years ago, but they seem to be correcting the invasive species mistakes by replanting with Maples and other native species as replacements are needed. We have a mix of Reds, Sugar and Freemans, so presumably that would help with pest issues to a degree. I guess nothing is entirely bulletproof though, so planting diversity is best.

 

[Northern Light]

Thanks for the all that info, very informative. It's funny you mention Crimson King Norways and Little Leaf Lindens, both were both heavily used in my neighbourhood when it was built ~40 years ago, but they seem to be correcting the invasive species mistakes by replanting with Maples and other native species as replacements are needed. We have a mix of Reds, Sugar and Freemans, so presumably that would help with pest issues to a degree. I guess nothing is entirely bulletproof though, so planting diversity is best.

On diversity, the common rule used by many in forest is known as the 10-20-30 rule:

Above from: https://www.deeproot.com/blog/blog-entries/is-the-10-20-30-rule-for-tree-diversity-adequate/

Even most knowledgable people don't typically refer to trees by their family groups.

In the case of Maples, for instance:

The species is Sugar Maple; (Acer saccharum )

The genus is Acer (maple)

But the family is Sapindaceae which also includes Horse Chestnut, Lychee, and Mexican Buckeye

*****

Oaks are part of the Fagaceae family (Beeches)

Which includes all the Oaks and Beeches as well as Chestnut

 

[isaidso]

Only a few tree species are shade tolerant (but still require light); but many of those aren't overly salt tolerant.

Probably the best combo is Basswood; its shade tolerant and pretty tough. Unfortunately, the City has tended over the years to use a European invasive variety 'Little Leaf Linden' rather than the native.

Sugar Maple and Black Maple will also tolerate shade, but its not good with salt at all, the City almost never uses it as a street tree.

Same problem w/Beech.

Black Ash takes some shade, but because of Emerald Ash Borer would not be planted.

Eastern Hemlock takes shade; but is not a canopy tree, as a conifer, and also needs its soil on the damp side, so would have to be irrigated.

Yellow Birch is salt tolerant, and a fast grower, and will take shade, but again, needs soil damp, so irrigation a must.

Thanks very much for the run down. I'm a big proponent of implementing greenery/flowers whenever possible. Perhaps when Toronto's tax base/km2 rises higher we can electrify all our downtown pavement like Oslo has done. They did a cost analysis and concluded that it would pay for itself quite quickly as they don't ever have to plough or salt nor do they see people end up at the hospital due to a slip and fall. Maybe wishful thinking on my part by no salting would also increase our tree options.

 

[Admiral Beez]

The city gave out free trees and shrubs at Riverdale Park West on Saturday, Somehow Metrolinx was also involved. Got myself a nice red oak. I’ve been wanting a free tree for years but the conditions on clearance between tree and properly line set by the city made it impossible for nearly every narrow house in Cabbagetown.

 

[gabe]

This past weekend all i heard was a symphony of leaf blowers in my neighborhood. I haven't raked my leaves in years. I got two large maples, and a hackberry tree on my property. Unless there is an excessive amount of leaves on the driveway, or sidewalks. i don't touch them. Come spring/summer time, my lawn looks as good as my neighbors who rake and remove every leaf off their lawn.

Scientists say don't rake leaves this fall. Here's why.

Scientists at the National Wildlife Foundation say that you shouldn’t feel obligated to rake up every last leaf in your yard this fall. Here are some tips on what you should do instead.

www.gardeningchannel.com

 

[Northern Light]

This past weekend all i heard was a symphony of leaf blowers in my neighborhood. I haven't raked my leaves in years. I got two large maples, and a hackberry tree on my property. Unless there is an excessive amount of leaves on the driveway, or sidewalks. i don't touch them. Come spring/summer time, my lawn looks as good as my neighbors who rake and remove every leaf off their lawn.

Scientists say don't rake leaves this fall. Here's why.

Scientists at the National Wildlife Foundation say that you shouldn’t feel obligated to rake up every last leaf in your yard this fall. Here are some tips on what you should do instead.

www.gardeningchannel.com

Excellent on your part!

Leaf Blowers are just an incredibly annoying, source of air and noise pollution.

When it comes to lawns and plant health, much better to let the duff (fallen leaves) dissolve mostly on their own. Its good for the soil.

If you rake a few into piles they may also serve as wildlife habitat.

In the spring, if they are a nuisance on a pathway or such, just sweep/rake them out of the way.

 

[gabe]

Excellent on your part!

Leaf Blowers are just an incredibly annoying, source of air and noise pollution.

When it comes to lawns and plant health, much better to let the duff (fallen leaves) dissolve mostly on their own. Its good for the soil.

If you rake a few into piles they may also serve as wildlife habitat.

In the spring, if they are nuisance on a pathway or such, just sweep/rake them out of the way.

Mother nature is better than any leaf blower on the market.

 

[DSC]

Down on Sugar Beach yesterday. The great avenue of maple there really looks in dreadful shape.

 

[Northern Light]

Down on Sugar Beach yesterday. The great avenue of maple there really looks in dreadful shape.

I was down there yesterday, you weren't fibbing! (not that I thought you were, LOL).

Though I wondered at first, because the very first few maples at the east end of the Promenade are in good shape.

But it didn't take me long to find this:

Likely partially caused by this, again: (Cottony Maple Scale)

Though, I have to say, I saw a lot less of that this year, looking at the trees vs last year. So I am wondering about other stressors, including, perhaps, that pipe work going on....hmmmm.

We did have drought stress earlier in the year, but most mature maples have fully recovered with the fall rains.

FWIW, the vast majority of these trees are alive and still have strong vigour, I checked. Branches are not brittle for the most part, good tensile strength. That said, I don't know how many years the trees will abide being this stressed before it takes a greater toll.

****

But lets end on a good note, the Maples of Sherbourne Common North:

 

[Northern Light]

A decent explainer column on the challenge of Norway Maples in Toronto, from The Star. (not paywalled at time of posting)

Here’s the shady secret behind one of Toronto’s most ubiquitous trees

We brought the invaders here. They’re thriving. They’re serving Toronto well. But do the Norway maples have to go?

www.thestar.com

 

[old boy]

A decent explainer column on the challenge of Norway Maples in Toronto, from The Star. (not paywalled at time of posting)

Here’s the shady secret behind one of Toronto’s most ubiquitous trees

We brought the invaders here. They’re thriving. They’re serving Toronto well. But do the Norway maples have to go?

www.thestar.com

In 1985 I planted rows of maples along my long country driveway. Half were Norways and half were Sugars. The Norways have thrived, the Sugars not so well. Through the years, I came to understand that I'd made a mistake in planting Norway Maple for a couple of reasons. Compared to native Sugar and Red Maples, the Norway Maple offers little to biodiversity and is quite overbearing with roots near the surface and seedlings going everywhere. I even decided to take the offending Norways down, until a Forestry friend advised that at least the fast growing Norways provided great shade and help keep the ground from drying out in our hot, dry summers. So, I left them in, but not letting them take over. What happens in the future to control this non-native when I'm gone, is moot.