s00f
New Member
Why is the city so insistent on planting Pin Oaks? It is very infrequently that I see them chosen and they are not failing spectacularly.
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- Thread starter Northern Light
- Start date
Northern Light
Superstar
Did you mean 'resistant' ?
The statement as worded is contradictory.
In any event. Pin Oaks are not native to Toronto. This is north of their natural range.
From: https://en.wikipedia.org/wiki/Quercus_palustris#/media/File:Quercus_palustris_range_map_1.png
The City actually does plant them as street trees from time to time. Frankly, I'd prefer they not. I'm mean they are near natives, but there are lots of native Oaks to Toronto that do quite well.
Red Oak, Bur Oak, White Oak, Black Oak * (generally a Savannah species) are all native, and all do fairly well in Toronto.
I'm not sure why the City would press for Pin Oak at the northern end of it range. The main advantage over say 'Red Oak' with which it might naturally produce a cross, would be that its fairly shallow-rooted making it an relatively easy transplant.
The City also regularly plants Swamp White Oak (near native); and is experimenting with Chinkapin as well (also near native).
s00f
New Member
Sorry for the confusing initial statement; I have seen them planted more and more in parks, and in newer developments, but they often languish and slowly die, seemingly without fail. Does the City take an inventory of the success/fail rate of each species?
Northern Light
Superstar
No worries.
Under recent leadership in Forestry (the last few years) there was a desire to use species native just a bit further to the south, supposedly as a hedge against climate change.
I argued against this, for a host of reasons, the easiest of which is simply that the climate (and thus the conditions for trees to reproduce) has not yet changed sufficiently for this to be a viable strategy.
Moreover, there is a material risk of introducing pests not yet present in Toronto's forests, a problem that is plenty bad already.
I lost that argument...........for now.
* ( I don't work for the City, but am engaged with City Forestry from time to time)
I hadn't taken any inventory myself. That's interesting, and I'll have to discuss that w/some experts in the field and get their take.
In general, not that I'm aware of....... however, newly planted trees are subject to a 2-year warranty from the nursery that supplies them, and the City does track its invocation of that (right to have a tree replaced).
That said, as Pin Oaks are a relatively recent experiment, it may be something they are keeping more of an eye on; I'll have to ask.
The trees planted for naturalization purposes are subject to different purchase lists, and different assessments vs street trees and trees that would be planted in 'tableland' (non-ravine) parks.
So far as I know, Pin Oak is not on the list for ESA (Environmentally Sensitive Area) locations.
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s00f
New Member
Thank you so much for your detailed answer!
W. K. Lis
Superstar
Wouldn't climate warming drive the native species northward?
Northern Light
Superstar
Yes, with time; though its generally a slow process. Movement in the right conditions might only be 3km per year w/o human intervention. So for nearby species (native to Niagara), you're still talking something that might take 5 decades; for a species based further south, say, Kentucky, a couple of centuries.
* this could happen faster, even w/o human intervention, depending on animal activity as many plant seeds move 'through' animals, and the latter can be more fast moving than plants.
***
But there are several problems with expediting any natural shift.
Trees (or other plants) that are native to a particular eco-system have an entire system adapted to them, and to which they are adapted. Birds that nest in them, insects that feed on them, soils for which they are adapted etc etc.
When you shift something out its habitat to a place with different soils, different insects, different plants and animals which have never been exposed to it, the results are somewhat unpredictable.
You may get trees that no bird wants to nest in; or no insects want to eat. A good example of this is the Ginko which landscape architects love, native to eastern Asia, virtually no insect, animal or bird in North America likes it or knows what to do with it.
So when you replace a native tree with a Ginko, you reduce habitat for native animals, birds and insects.
You also have the risk of bringing an unexpected disease/pest from further south, for which your local ecosystem has no defense.
On top of all that, there are two risks at opposite extremes; one that the transplants will not do well in their new home, for the reasons noted above, and because they may not be suited to this particular climate in its current form (if a tree can't survive a winter's night at - 20, it doesn't matter what the night time low will be in 2042, the tree will die this winter), the tree may also encounter pests/diseases here that it would not experience in its natural system.
At the other end of the spectrum, there is a risk the tree will do too well here, and become invasive. If the tree is adaptable to local conditions, but has nothing that eats it or preys on it, then it has an unnatural
advantage over its local competitors. As a result, it can displace them. It may turn some local species into endangered species, or may even extirpate them (make them locally extinct) entirely.
Norway Maple is a good example of this locally, native to Europe, this salt-tolerant, urban-pollution tolerant tree is in a position to out compete our local maples and oaks and indeed, increasingly wipes out biodiversity in many of our ravines, as few things can grow under its dense shade.
This can happen with species native to North America, but further south, as well. Black Locust would be a good example.
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Midtown Urbanist
Superstar
One of my favourite books that I've read this year was The Hidden Life of Trees by Peter Wohlleben. I'd like to continue learning more on the subject. Do you @Northern Light or anyone else have any recommendations?
Northern Light
Superstar
Not squarely on trees, but on forest, you might find this one interesting:
The Forest Unseen: A Year's Watch in Nature: Haskell, David George: 9780143122944: Amazon.com: Books
Buy The Forest Unseen: A Year's Watch in Nature on Amazon.com ✓ FREE SHIPPING on qualified orders
www.amazon.com
Still available in paperback at Indigo.
People's taste in writing style varies, so I would I always suggest reading a bit in store or online first to see if its your cup of tea.
Its a very detailed look at the life of just 1m2 of forest in Tennessee.
***
There are other good tree-focused resources specific to Ontario, but they might be better termed as field guides or text books as opposed to a good 'read' per se.
Trees in Canada is one of the better texts:
Trees In Canada
<p><b><i>Trees in Canada</i> is celebrating its 100th anniversary (1917 to 2017)</b><br /> with a redesigned reprint that has a modern look. It features a striking new cover and an easier-to-read, engaging content with a new font and standardized photographs many of which bleed.</p><p>Two new...
www.chapters.indigo.ca
There are several specific to Ontario:
This one is currently out of print, but you might find it just the same:
Trees of Ontario: Including Tall Shrubs
<DIV>A complete guide to the many deciduous and coniferous trees and shrubs found in Ontario, Canada's most populous and diverse province. Includes Bibliography, Glossary, Index, and range maps. Illustrated with color photographs and illustrations throughout.</DIV>
www.chapters.indigo.ca
ROM has a brand new field guide for Ontario coming out in April '23:
A Field Guide To Trees Of Ontario
This field guide is one in a series of ROM guides that are beautiful pocketbooks that connect readers with nature and wildlife across the province of Ontario. Packed with information on the biology, habitat, and conservation of the featured species, the books provide quick and easy access to...
www.chapters.indigo.ca
s00f
New Member
Here is some green to brighten up your feed: some giant Northern Red Oaks (Quercus rubra) I saw last year!
Northern Light
Superstar
@s00f
I did as I promised above........and here is what I heard back.
"Pin Oaks are dying in Toronto, and very few are making it to anything close to maturity. I would not plant one on a go-forward basis" ; " The reason for this is that they prefer acidic soils and Toronto is principally alkaline soil; it doesn't instantly kill Pin Oaks, but they can only deal w/it for so long"
"The alkaline soil interferes w/the trees ability to absorb Iron, this is refereed to as Iron Sclerosis"
What is Iron Chlorosis and What Causes it? | Forestry | Extension
What is iron chlorosis and how it is caused and affects various types of trees? Forestry Extension at Utah State University
From the above:
s00f
New Member
Perfect; this really clears up why pretty much all of them seem to be slowly dying in the same way.@s00f
I did as I promised above........and here is what I heard back.
"Pin Oaks are dying in Toronto, and very few are making it to anything close to maturity. I would not plant one on a go-forward basis" ; " The reason for this is that they prefer acidic soils and Toronto is principally alkaline soil; it doesn't instantly kill Pin Oaks, but they can only deal w/it for so long"
"The alkaline soil interferes w/the trees ability to absorb Iron, this is refereed to as Iron Sclerosis"
What is Iron Chlorosis and What Causes it? | Forestry | Extension
What is iron chlorosis and how it is caused and affects various types of trees? Forestry Extension at Utah State Universityforestry.usu.edu
From the above:
View attachment 448571
just east of the creek
Active Member
Northern Light - slightly off the topic of pin oaks. How about American Chestnuts? Mainly at the limit of their range in and around Toronto and Southern Ontario below Hwy 7, listed as a species at risk in Ontario, mainly due to the ravages of chestnut blight, and now subject to a lot of news coverage and debate re the proposed release of a generically modified American Chestnut. Like Elms, American Chestnuts would be a welcome addition to our forest canopy - say at a one for one replacement ratio with Norway Maples? But does the genetic modification of this tree, adding an extra gene to the tree's dna to assist with the process "that detoxifies but does not kill the fungal blight’s otherwise deadly oxalic acid while emitting two off gases (hydrogen peroxide and carbon dioxide) in tiny quantities" invalidate its use? We struggle with this question with crops (its a ongoing argument every planting season at home) yet we have been modifying plants for thousands of years, II find no mention of genetics in city documents related to forest management. I am interested in whether the forum has any strong yay or nay feelings on the subject.@s00f
I did as I promised above........and here is what I heard back.
"Pin Oaks are dying in Toronto, and very few are making it to anything close to maturity. I would not plant one on a go-forward basis" ; " The reason for this is that they prefer acidic soils and Toronto is principally alkaline soil; it doesn't instantly kill Pin Oaks, but they can only deal w/it for so long"
"The alkaline soil interferes w/the trees ability to absorb Iron, this is refereed to as Iron Sclerosis"
What is Iron Chlorosis and What Causes it? | Forestry | Extension
What is iron chlorosis and how it is caused and affects various types of trees? Forestry Extension at Utah State University
From the above:
View attachment 448571
Northern Light
Superstar
Interesting question.
In terms of City policy, I'm unaware of a new one specific for this species, but will have to ask around.
In general, I imagine it would deemed a 'cultivar' and therefore considered acceptable as a street tree, but not for planting in natural areas. (this is the way the cross breeding of American Elms with non-North American Elms to enhanced Dutch Elm Disease resistance has been treated)
The City plants the cultivars as street trees; but only plants 'pure' elms in forests. The latter do have versions that are 'pure' native which are showing some increase in resistance, as specimens that resistant the disease have been used as seed source.
Elm Recovery Project | The Arboretum
arboretum.uoguelph.ca
Amercian Chestnut should be more common here; definitely not as common as Norway Maple is now. I don't recall they're ever being ubiquitous in Toronto, but there was a significant population of them in the Rouge. Also, generally, a relatively short tree, with most topping out at ~10m; though the odd long lived one has managed to get to 3x that size. As such, I wouldn't generally used it to replace canopy trees; but more large shrubs (Alternate-Leaf/Pagoda Dogwood, if you were thinking native, or European Buckthorn if you were thinking invasive)
Memph
Active Member
I didn't say it was a conifer, just an evergreen (non-deciduous) magnolia. I took a couple more pictures on Jan 2 but was kind of shy about walking right up to it to take pictures since it's on private property. It can basically only be Sweet Bay or Southern Magnolia at this point imo, and I'm leaning towards Southern Magnolia due to the way the leaves look (especially the brownish colouration on some of the undersides). Which is kind of neat since I think it might be the furthest north occurrence of a Southern Magnolia east of the Rockies?
The bottom half of the tree is obscured by rhododendron which have somewhat smaller leaves.
