This question is born out of a lack of knowledge on my part, and it should be said I am someone who frequently overwaters plants:
Is there a knowledge gap in planning this or other projects, specifically recent research or strategies surrounding the type of planting described above? It seems like there is a high risk to many aspects that might force future dollars to be spent repair the area. As someone unfamiliar with this world, I would imagine the longevity of the planting is high on the priority list so future money isn't required.
Or is this more of a situation where there could be differing opinions on what will work and what will not work?
I don't know/haven't asked yet, which agency spec'ed the details.
So I won't slag anyone, as I neither know the responsible party, nor have I heard their reasoning.
On the species chosen, honestly, I've seen very suspect choices lots of times come from Forestry and the TRCA. Both have competent people who care, but both also have green staff w/o the requisite knowledge. They know what native is, may read off a list for sunny/shady plants.........but they're new, and just missing real-world knowledge.
Things like growth rates of different species. Many also don't take the time (in fairness may not be given the time) to understand the sites on which they are planting (ie. if someone walked this site in mid-August after 10 days w/o rain, it would be average moisture to slightly dry; much different than it is in the spring.
This is why you need to look at sites more than once, ideally, (old pictures may be fine), but you want an understanding of how a site behaves or changes nature at different times of year.
Species choice should not be, but may also be influenced by easy availability from a preferred vendor.
Toronto rarely spec's Bitternut Hickory or Buttternut, even though both are native and belong through much of Toronto. But they are slow growers and not all that widely available in the nursery trade. This may mean extra paperwork and ordering from a specialty vendor.
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On the size of the trees........this is only a guess......but because they had to cut down quite a few trees to do the work on the creek banks, this is likely a 'compensation planting' which comes with a formula of 3 or 4 to one, typically.
The thing is, if you're trying to replace canopy, or shade, you may feel you should be planting trees with a head start that provide canopy more quickly. There is a case for that, I suppose, but the trade-offs are dubious in my opinion.
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In general, the City is getting a bit better at stewarding old planting sites, but its still a bit hit and miss in terms of a thoughtful, consistent approach. This site, is likely a one-off capital project funded by Toronto Water, and I doubt it will be stewarded much beyond the warranty period for the trees (typically 2 years)
Though maybe Toronto Nature Stewards could look into it.
