The Toronto Tree Thread

[Northern Light]

What about the place of origin of the tree? I read somewhere that sometimes our nursery trees are grown in the US quite a bit south of here. When I was a kid we planted a red maple from Muskoka in our back yard and it always turned red and shed it's leaves early. Does the tree adapt completely or always retain some of it's inherited range of behaviour?

You are correct.

The tree's origin matters, so does the origin of its seed.

For naturalization projects it is typical to specify the climate zone of the seed.

The issue is at you point out, trees from different climate zones are adapted to those zones.

So your Red Maple had a shorter growing season, because the growing season is shorter in Muskoka.

Likewise, a Red Maple source from Kentucky will have a longer growing season.

However, it will also not be cold hardy, in part for that very reason. The tree will try to keep growing through lower light levels and colder temperatures into November, and when the cold hammers it, it will be in trouble.

It would likely die, but at the very least it would die-back, and shed multiple branches as it tried to conserve itself.

***

In respect of adaptation, no a tree can not adapt during its own lifetime.

It may adapt its seeds.


***

There is some discussion in the forest gene ecology community about all of this, in relation to climate change.

Some suggest that we might want to purchase trees/seeds from one climate zone south (but not futher) so that trees will be better adapted over the course of their lives.

One climate zone south is Lake Erie, North Shore.

 

[Northern Light]

Glad this thread was created, I have already learned a lot. I also like that it is in the Infrastructure forum, I believe trees should be recognized as part of our infrastructure.

Question: Are there any particular downtown(/and area) developments where one could point to and say that the developer did a really good job in selecting, planting and protecting the trees in the project? I'm afraid that these are not details that I personally make note of (partially due to my own personal ignorance on the subject) when I walk by development projects. So I am curious what 'getting it right' looks like, and more importantly, why they got it right.

I'm glad you're finding it useful!

In terms of protection, I can't think of a fully private one off-hand that makes me go wow.

But I can give a semi-private one, in that its non-City. Grange Park.

You'd think that's the City, but the managing proponent was AGO.

They did a very good job protecting their trees.

***

In terms of planting. I always use Maple Leaf Square as an example, York Street frontage. The trees there are so robust they may need to be thinned out soon. They clearly got great specimens and put them in very good growing conditions and they also chose their species well.

The park at the corner of Blue Jays Way and Front is also showing high-performance w/its trees. Its a City park, but I imagine it was built by the developer (Tridel, if I recall).

Eaton Centre, Dundas frontage is also doing quite well these days. Again, lots of open soil, lots of room to grow, lots of access to water, and high-curbs and a set back from the street that reduce salt exposure.

 

[Northern Light]

So I read this article and I understand the dilemma posed by the Norway Maple. It is effectively creating a green desert where it's invasiveness is reducing the biodiversity of the canopy and the ravine as a whole.

What can actually be done about it?

Not planting any more would be a good start.

They're not supposed to be planted by the City, but many Crimson Norway Maples (purple leaves most of the year) were put into the redone streetscape on Danforth Avenue east of Woodbine. (they were not in the specs).

Private developers still plant them too, and the LCBO just put some in one of their nearby parking lots.

Sigh.

Not helpful.

***

Beyond that, they can be actively managed (by which I mean killed, either by taking them down outright, or by girdling (think strangling the tree by making small cuts around the base level, that cut off its sap flows).

Removing all of them would be prohibitively expensive and impractical.

The focus should be on removing them from natural areas, where they are already highly invasive AND a threat to a high quality natural area; or where they are just one tree, but in/adjacent to a high-quality habitat.

Some of that does go on now, but not enough.

Forestry is very afraid of angry neighbours/parks users seeing a clear cut in their forest.

Its also expensive. Clearing a Norway-dominant patch of land that is filled w/mature trees will run you between $30,000 - $70,000 per acre.

 

[pman]

Not planting any more would be a good start.

They're not supposed to be planted by the City, but many Crimson Norway Maples (purple leaves most of the year) were put into the redone streetscape on Danforth Avenue east of Woodbine. (they were not in the specs).

Private developers still plant them too, and the LCBO just put some in one of their nearby parking lots.

Sigh.

Not helpful.

***

Beyond that, they can be actively managed (by which I mean killed, either by taking them down outright, or by girdling (think strangling the tree by making small cuts around the base level, that cut off its sap flows).

Removing all of them would be prohibitively expensive and impractical.

The focus should be on removing them from natural areas, where they are already highly invasive AND a threat to a high quality natural area; or where they are just one tree, but in/adjacent to a high-quality habitat.

Some of that does go on now, but not enough.

Forestry is very afraid of angry neighbours/parks users seeing a clear cut in their forest.

Its also expensive. Clearing a Norway-dominant patch of land that is filled w/mature trees will run you between $30,000 - $70,000 per acre.

Forestry certainly wasn’t afraid of neighbourhood opinion when it clear-cut Chorley slope. Which of course is now eroding in spite of the incredible amount of armour stone they installed.

 

[Northern Light]

Forestry certainly wasn’t afraid of neighbourhood opinion when it clear-cut Chorley slope. Which of course is now eroding in spite of the incredible amount of armour stone they installed.

The Chorley slope has not been a well managed project on any number of levels; I can't really say much more.

The decision to put the connection in, as a switch-back necessitated a great deal of the cutting, much of which was non-native and invasive.

But let's be clear the department took enormous flack for that.

I consider that the least sinful thing about this project.........

The Moore Park/Beltline Ravine is dominated by Norway Maple, as someone w/an appreciation of healthy forests, I always consider it slightly depressing walking down there seeing how little diversity of native plant material is there.

At any rate, you might be happy to know the contract has been let to replant the slope, it will happen the fall, and the forestry company hired is highly competent (I have no affiliation, but I know their work)

 

[Northern Light]

I'm going to add another example of planting done right. All of the stuff done by Daniels, along Dundas, east of Parliament as part of the Regent Park renewal.

Its performing extremely well. I was just walking past it this evening and took note of that in light of discussions here, tree growth is very good, very few distressed specimens, you can see the design feature
yet again, long planters, open soil, 2-3 trees per planter, set back from the road, with seat-high walls/curbs that limit salt exposure. Four stars out of Five. They lose some points for lack of diversity, its a bit of a monoculture and if anything goes wrong for that type of tree, could be a problem. Otherwise, very well done.

 

[WislaHD]

I'm going to add another example of planting done right. All of the stuff done by Daniels, along Dundas, east of Parliament as part of the Regent Park renewal.

Its performing extremely well. I was just walking past it this evening and took note of that in light of discussions here, tree growth is very good, very few distressed specimens, you can see the design feature
yet again, long planters, open soil, 2-3 trees per planter, set back from the road, with seat-high walls/curbs that limit salt exposure. Four stars out of Five. They lose some points for lack of diversity, its a bit of a monoculture and if anything goes wrong for that type of tree, could be a problem. Otherwise, very well done.

These ones I take it?

Interesting that around the corner from the above, along Sumach, the trees are given a different treatment, immediately adjacent to the street and not in a grade-separating planter, and they do look a little bit sadder compared to the the ones pictured above, perhaps driving home the point. (Though, the streetview photos are dated to a year ago.)

 

[Northern Light]

These ones I take it?

View attachment 153950

Interesting that around the corner from the above, along Sumach, the trees are given a different treatment, immediately adjacent to the street and not in a grade-separating planter, and they do look a little bit sadder compared to the the ones pictured above, perhaps driving home the point. (Though, the streetview photos are dated to a year ago.)

Correct.

 

[steveintoronto]

A surprisingly good read from a non-arborist:
https://www.theglobeandmail.com/canada/toronto/article-hey-urbanites-ugly-trees-need-love-too/

 

[MrSocky]

You are correct.

The tree's origin matters, so does the origin of its seed.

For naturalization projects it is typical to specify the climate zone of the seed.

The issue is at you point out, trees from different climate zones are adapted to those zones.

So your Red Maple had a shorter growing season, because the growing season is shorter in Muskoka.

Likewise, a Red Maple source from Kentucky will have a longer growing season.

However, it will also not be cold hardy, in part for that very reason. The tree will try to keep growing through lower light levels and colder temperatures into November, and when the cold hammers it, it will be in trouble.

It would likely die, but at the very least it would die-back, and shed multiple branches as it tried to conserve itself.

***

In respect of adaptation, no a tree can not adapt during its own lifetime.

It may adapt its seeds.


***

There is some discussion in the forest gene ecology community about all of this, in relation to climate change.

Some suggest that we might want to purchase trees/seeds from one climate zone south (but not futher) so that trees will be better adapted over the course of their lives.

One climate zone south is Lake Erie, North Shore.

I can only speak from my experience working at a commercial nursery and anecdotal opinions, I have no formal education behind any of this. A majority of all bare root stock and smaller saplings we planted out in our fields, came from BC. We assumed that roughly 30% of all BC plantings would die in their first winter, just from an inability to acclimate to the cold. We always wintered our plants for 2 years in Ontario before we sold them to our customers, after this point the winter mortality rate typically stabilizes for us.

In the past we ordered from areas such as Kentucky and Tennessee, but would assume a 50-60% mortality rate in the first winter due to the climates being so different. This was feasible with a stronger dollar, but with the current state of our dollar it does not make sense financially.

From my experience with other nurseries, just about everyone we dealt with ordered in from BC and took the same approach. BC's mild climate and longer growing season allows them to deliver a plant at the same size as a purely Ontario grown one at less than half the price. Even with the 30% mortality rate and shipping, you still come out ahead. If anyone is interested in a native Ontario approach Verbinnen's Nursery is very cool, they use exclusively native seed stock to Ontario and only grow native plants. We've dealt with them a bit, but typically we required larger plants than they had available.

 

[TrickyRicky]

That’s interesting regarding the BC tree farms. It made me curious so I roughly calculated that those BC farms if they are in the south of that province are over 600 km north of Toronto. BC has a milder winter climate than Toronto but does that mess with the tree? In my previous Muskoka example the tree we took was no more than 200 km north of the City.

 

[Northern Light]

I can only speak from my experience working at a commercial nursery and anecdotal opinions, I have no formal education behind any of this. A majority of all bare root stock and smaller saplings we planted out in our fields, came from BC. We assumed that roughly 30% of all BC plantings would die in their first winter, just from an inability to acclimate to the cold. We always wintered our plants for 2 years in Ontario before we sold them to our customers, after this point the winter mortality rate typically stabilizes for us.

In the past we ordered from areas such as Kentucky and Tennessee, but would assume a 50-60% mortality rate in the first winter due to the climates being so different. This was feasible with a stronger dollar, but with the current state of our dollar it does not make sense financially.

From my experience with other nurseries, just about everyone we dealt with ordered in from BC and took the same approach. BC's mild climate and longer growing season allows them to deliver a plant at the same size as a purely Ontario grown one at less than half the price. Even with the 30% mortality rate and shipping, you still come out ahead. If anyone is interested in a native Ontario approach Verbinnen's Nursery is very cool, they use exclusively native seed stock to Ontario and only grow native plants. We've dealt with them a bit, but typically we required larger plants than they had available.

Verbinnen's is excellent. I concur w/that endorsement.

 

[Northern Light]

That’s interesting regarding the BC tree farms. It made me curious so I roughly calculated that those BC farms if they are in the south of that province are over 600 km north of Toronto. BC has a milder winter climate than Toronto but does that mess with the tree? In my previous Muskoka example the tree we took was no more than 200 km north of the City.

Yes, it messes with the tree. Err, well, it messes w/the trees parent. Its the seed that is adapted to a particular climate/region more than anything.

The tree may adapt some in life, but not much.

It would be like asking you to change your height. You may learn to deal w/being shorter, but your height won't change.

The tree is adapted to a certain growing season and temperatures before it first sprouts, and will usually be more challenged in a different climate.

 

[WislaHD]

I am following up the discussion from the Valhalla Town Square thread to here.

I'm sceptical of the air quality near the 427.

It's bad, but not as bad as it is for those living just down the highway around Sherway. Those people are breathing in a nice cesspool of pollutants daily:

I'm going to page @Northern Light for his insight here, but I think there should be some sort of City Planning policy that mandates many many more trees be planted in all developments along the 427 corridor than typical.

Would that be an effective measure to combat the air quality of the area?

So far as I know, currently, there are no municipal policies or provincial ones that target tree plantings (public or private) based on combating pollution/particulate matter or the urban heat island. (or that matter even augmenting biodiversity). By and large planting policies, where they exist, are opportunistic, rather than strategic.

The province does have a policy of planting trees on rural farm area 400-series highways ever since the big snow-out on 403 a few years ago near Sarnia.

They now have a policy to plant double-rows of White Spruce to create a barrier to drifting snow.

But no similar mandate exists for urban highways for that or any other reason.

The MTO used to have a mandate to consider pollution and aesthetics when re-doing interchanges. You can see a few that got fairly dense forest treatments in past years.

That policy was canned almost 2 decades ago during a round of provincial cutbacks.

In respect of private development, the City's base-level policies are focused on retaining or replacing trees removed for development (3 for 1), protecting and enhancing ravine areas, stream bank stability protection, and meeting
targets for storm-water run off and permeability.

There aren't, for the most part, tree planting targets for any given development (though, streetscape plans may dictate this in some cases).

There is certainly no geography based idea of requiring greater tree planting of a developer because of greater need in a given area, nor is there any similar focus/target on public sector lands.

In terms of gaining a critical mass of trees in this section of the City, the best opportunity lies in Centennial Park in Etobicoke; and Clairville Conservation area by Brampton.

Both could easily supports several hectares and more than 100ha respectively of additional forest without removing any existing community amenities. Though I'm all for targeting redevelopment or existing parking areas in big box land and at Sherway; but you won't get as many trees on those sites as the parklands I noted and costs will be greater.

In respect to the air quality map posted above, you said that (if I got this correct) that the best means of improving air quality over the 427 lays in expanding tree coverage in Centennial Park and Clairview Conservation Area. Should this be interpreted as saying that even if every acre of parking lot and big box store along the 427 was redeveloped to more intensive use, with a high concentration of trees planted on every site, that it would have only negligible impacts on air quality in the area?

I suppose another interesting question brought up, is whether we (municipality) should have planning tools to mandate more trees planted on site in a redevelopment to serve a particular planning purpose (some purposes could be improving local air quality, reducing run-off, reducing local heat island effect). However, I am getting an impression that such benefits would only be negligible?

 

[Northern Light]

I am following up the discussion from the Valhalla Town Square thread to here.

In respect to the air quality map posted above, you said that (if I got this correct) that the best means of improving air quality over the 427 lays in expanding tree coverage in Centennial Park and Clairview Conservation Area. Should this be interpreted as saying that even if every acre of parking lot and big box store along the 427 was redeveloped to more intensive use, with a high concentration of trees planted on every site, that it would have only negligible impacts on air quality in the area?

I suppose another interesting question brought up, is whether we (municipality) should have planning tools to mandate more trees planted on site in a redevelopment to serve a particular planning purpose (some purposes could be improving local air quality, reducing run-off, reducing local heat island effect). However, I am getting an impression that such benefits would only be negligible?

I am following up the discussion from the Valhalla Town Square thread to here.

In respect to the air quality map posted above, you said that (if I got this correct) that the best means of improving air quality over the 427 lays in expanding tree coverage in Centennial Park and Clairview Conservation Area. Should this be interpreted as saying that even if every acre of parking lot and big box store along the 427 was redeveloped to more intensive use, with a high concentration of trees planted on every site, that it would have only negligible impacts on air quality in the area?

I suppose another interesting question brought up, is whether we (municipality) should have planning tools to mandate more trees planted on site in a redevelopment to serve a particular planning purpose (some purposes could be improving local air quality, reducing run-off, reducing local heat island effect). However, I am getting an impression that such benefits would only be negligible?

Hmmm, I wouldn't say negligible.

Here's what I would say. To offset the kind of pollution a major highway corridor currently generates is not something resolved by 10 trees or 100 trees or 1000 trees.

Of course each number of trees can contribute to a greater whole.

But if you're looking for an impactful, timely result, expecting that from redevelopment of any one private land holding is unlikely (though not impossible).

The Sherway Gardens site is large enough to be impactful if you make 1/2 of it forest.

But doing so outright (removing development) is both improbable and expensive).

The question then becomes what can you achieve?

That obviously depends on the size of any one site, but also on what you want to do with it and at what cost.

Let's go back to Sherway. If all the parking were topped by a 'green roof' you could achieve wonders, providing that roof supported full-sized trees.

But that's a lot of expensive engineering, relative to retaining only parking spaces.

If you slap down condos and simply set aside a 10 or even 20m buffer to the highway, no that won't make an exciting difference.

Its not that it will do nothing, but I have my doubts that you could measure the impact on air quality with any but the most sensitive equipment.

That then leaves the question of how you might address that?

If every condo or mall goes green roof, engineered to handle large trees, that would add up.

But the economics may be challenging.

The issue in the short-term is critical mass planting, especially in economically favourable ways.

Longer term, you have to consider moving new ideas into the Green Standard, in respect of air quality, first voluntary, ultimately mandatory.

***

A truly massive difference? Deck over the highway with green-roof deck and plant trees, vent the particulate matter through low-grade filters (removing the worst of the pollution) then let it vent into and above the new tree line.

But this is not a cheap proposal.

One needs to consider balancing different ideas such as major investments in public transport that would allow a narrower R.O.W. as well as mandates for cleaner cars/trucks.

One could consider building over the ROW of the highway, instead of beside it, and using the adjacent land as the green filter.

Lots of options. Limited only by ambition and dollars.