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The Toronto Tree Thread

pman

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The photos are remarkable! For once a Toronto project that actually looks like the renders.
 

Northern Light

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For those that take a keen interest on tree mortality in streetscapes, with a particularly emphasis on salt.......

Online webinar discussing this, in particularly looking at Bloor Street and Queen's Quay Very informative!

Warning, run time is 1hr 18

 
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Northern Light

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To follow up on the above.

The study of Bloor Street took place in 2015 and was examining causes of mortality.

No surprise with the conclusions, to me.

  1. Leading cause of mortality, salt, higher concentrations in soil near dead/dying trees vs healthy ones.
  2. Survival/health was much better in curb/surround planters vs the circular, in sidewalk tree pits.
  3. Secondary health issue was low levels of sunlight; evidence that many preferred species for street trees require high levels of sunlight.
My Comment:

The two most shade tolerant, native trees, are Sugar Maple and Basswood; both are highly intolerant to salt.

This may indicate a need to create especially salt-reduced conditions for lower light areas, so that the above species can be planted.

The Study of Queen's Quay sampled tree leaves and tissue for salt levels and clearly showed salt levels to be in the toxic range (ie. salt levels high enough to induce tree mortality)
 

WislaHD

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This whole post deserves to be quoted here.

IMO the bigger issue with the trees comes with their viability due to their exposure, and the inevitable requirement for replacement.

While there have been some comparisons made to Singapore, I have to say that those comparisons are missing some points. Rooftop vegetation works in subtropical Singapore, where the climate is warmer, the air more humid, and where trees will literally grow anywhere even if you don't ask them to- but in cold and windy Toronto? Much harder to do IMO.

Heck, a few years ago, it took some considerable logistics and cost about half a million to replace an oak tree which had died on top of a 17-floor Vancouver condo, which I would consider a fairly temperate climate compared to Toronto. The previous tree died after a single season of drought. On top of that, they had to redo the degraded waterproofing- which is always a concern with rooftop plants (think of College Park's renovations, the vegetation chosen there was chosen as it was expected that the waterproofing membrane would need to be replaced again in the future)- does this mean that the trees have a definitive lifespan?

https://bc.ctvnews.ca/oak-tree-with-554k-price-tag-hoisted-to-top-of-condo-building-1.3661213

Now think about the trees on this building- how are we going to replace them? A crane (not currently present)? Stuffing the trees into the elevators? Is there going to have to be some shelter created for trees to help them survive their first few years? It's really more trouble than it's worth- I would not be surprised if these trees disappeared in the next refinement of Union Centre (or became containerized shrubs).

This article from a few years back puts it into words clearly:


There are plenty of scientific reasons why skyscrapers don’t—and probably won’t—have trees, at least not to the heights which many architects propose. Life sucks up there. For you, for me, for trees, and just about everything else except peregrine falcons. It’s hot, cold, windy, the rain lashes at you, and the snow and sleet pelt you at high velocity.Life for city trees is hard enough on the ground. I can’t imagine what it’s like at 500 feet, where nearly every climate variable is more extreme than at street level.

Wind is perhaps the most formidable force trees face at that elevation. Ever seen trees on the top of a mountain? Their trunks bow away from the prevailing winds. That may be the most visible effect, but it’s not the most challenging. Wind also interrupts the thin layer of air between a leaf and the atmosphere, known as the boundary layer. The boundary layer is tiny by human standards—it operates on a scale small enough that normally slippery gas particles behave like viscous fluids.

For plants, the boundary layer serves to control evapotranspiration, or the loss of gas and water through the tiny pores on a leaf’s underside, known as stomata. In calm conditions, a comfortably thick boundary layer can exist on a perfectly smooth leaf. But plants that live in hot or windy places often have adaptations to deal with the harsh conditions, including tiny hairs on their leaves that expand each leaf’s surface area and thus its boundary layer. Still, plants in these environments aren’t usually tall and graceful. In other words, not the tall trees we see in architectural drawings.

Next let’s add extreme heat and cold to the mix. Extreme cold, well, we all know what that does. It can kill a plant by turning the water inside its cells into lethal, crystalline knives. At the other end, hot conditions post a different set of challenges. To cool off, plants can “sweat” by opening their stomata to release water vapor, at least as long as there’s water available. But even then, plants reach a limit. At certain temperatures, which vary from plant to plant, the photosynthetic machinery inside a leaf starts to break down. Keep in mind these are temperatures on the surface of a leaf, not ambient air temperature. The surface of a leaf—especially in direct sunlight, as on the unshaded side of a skyscraper—can be many degrees hotter than the air, up to 14 degrees C in some species (nearly 26 degrees F).

Then there are the logistical concerns. How are these trees going to be watered and fertilized? Pruned? How will they be replaced? How often will they need to be replaced? As someone who grows bonsai, I can tell you that stressed plants require constant attention—daily monitoring, in fact, and sometimes even more frequently. It’s not easy. Growing simple green roofs is a chore, and those plants are chosen for their hardiness and low maintenance. Trees are generally not as well-adapted to the wide range of conditions likely to be experienced on the side of a skyscraper.
 

DSC

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The Auditors have been looking at TREE MAINTENANCE....

"The key findings from the audit report are:

Urban Forestry requires each contractor and City crew to complete a daily log detailing the maintenance work performed and all other work-related activities within their eight-hour shift. The daily logs serve as the proof of work performed by the crews, and Urban Forestry pays the contractors according to work hours reported in their daily logs. Part of our audit included a comparison of the daily logs with the contractor crews' vehicle Global Positioning System (GPS) reports. We could not conduct the same comparative analysis for City crews because Urban Forestry's vehicles are not equipped with a GPS system.

We compared a sample of 45 contractor crews' daily logs with their vehicle GPS records and noted 28 of them contain one or both of the following issues:

Crews' vehicles did not stop near the tree service locations.
Vehicles went to locations that were not related to the assigned tree service locations (e.g., coffee shops, plazas, residential houses, streets with no trees), and these locations were not noted in their daily logs. The total time spent at these locations far exceeded the allowable 60 minutes for lunch and breaks.

This could mean that part of the 8-hour work paid by the City was not spent on City work related activities. The estimated potential loss in productivity is approximately $2.6 million per year.

Also, if an inaccurate maintenance record is created for a tree in Urban Forestry's system, this could have adverse long-term effects because it may be at least another seven years before the tree receives the next scheduled maintenance.

After deducting the average time spent on supporting activities, the on-site tree maintenance time for the 28 contractor crews' daily logs averaged 4.5 hours, of which 1.7 reported work hours were not supported by the GPS reports, leaving only 2.8 hours for tree maintenance work for the City.

We reviewed a sample of 139 daily logs from the City and contractor crews and noted 57 logs (41 per cent) have missing data or contain entries that should have been questioned. While some of these entries might be valid, none of them were identified by the Foreperson's review.

This report provides 10 recommendations to help Urban Forestry improve its contract management, customer service and operational efficiency for its tree planting and maintenance programs."

See: http://app.toronto.ca/tmmis/viewAgendaItemHistory.do?item=2019.AU2.4
 

ssiguy2

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What the hell is a Tree thread doing in the transportation forum?………...please mods, move this thread over to an appropriate forum section.
 

Northern Light

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The Auditors have been looking at TREE MAINTENANCE....

"The key findings from the audit report are:

Urban Forestry requires each contractor and City crew to complete a daily log detailing the maintenance work performed and all other work-related activities within their eight-hour shift. The daily logs serve as the proof of work performed by the crews, and Urban Forestry pays the contractors according to work hours reported in their daily logs. Part of our audit included a comparison of the daily logs with the contractor crews' vehicle Global Positioning System (GPS) reports. We could not conduct the same comparative analysis for City crews because Urban Forestry's vehicles are not equipped with a GPS system.

We compared a sample of 45 contractor crews' daily logs with their vehicle GPS records and noted 28 of them contain one or both of the following issues:

Crews' vehicles did not stop near the tree service locations.
Vehicles went to locations that were not related to the assigned tree service locations (e.g., coffee shops, plazas, residential houses, streets with no trees), and these locations were not noted in their daily logs. The total time spent at these locations far exceeded the allowable 60 minutes for lunch and breaks.

This could mean that part of the 8-hour work paid by the City was not spent on City work related activities. The estimated potential loss in productivity is approximately $2.6 million per year.

Also, if an inaccurate maintenance record is created for a tree in Urban Forestry's system, this could have adverse long-term effects because it may be at least another seven years before the tree receives the next scheduled maintenance.

After deducting the average time spent on supporting activities, the on-site tree maintenance time for the 28 contractor crews' daily logs averaged 4.5 hours, of which 1.7 reported work hours were not supported by the GPS reports, leaving only 2.8 hours for tree maintenance work for the City.

We reviewed a sample of 139 daily logs from the City and contractor crews and noted 57 logs (41 per cent) have missing data or contain entries that should have been questioned. While some of these entries might be valid, none of them were identified by the Foreperson's review.

This report provides 10 recommendations to help Urban Forestry improve its contract management, customer service and operational efficiency for its tree planting and maintenance programs."

See: http://app.toronto.ca/tmmis/viewAgendaItemHistory.do?item=2019.AU2.4
Hopefully the recommendations will pass.

But rather sad that we need to resort to that level of oversight/compliance, it adds to costs. Probably not as much as the current waste, but still.......sigh.

*****

In regards to the in-house crews, this recommendation is important:

c. assessing ways to reduce wait time for crews at the City yards, particularly at the end of each shift

The City crews lose a lot of time at the beginning/end of shifts to the various processes to/from City yards.

Some of that is unavoidable; but some is.......worthy of another look.
 
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Northern Light

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What the hell is a Tree thread doing in the transportation forum?………...please mods, move this thread over to an appropriate forum section.
You missed the 'And Infrastructure' part of the Forum title.

City owned trees are an 'asset' on the books, and they do serve functional purpose as infrastructure in regards to air/water quality, reduction/mitigation of floods, reduction of urban heat island effect, slope stability/erosion prevention and aesthetics.

This is the correct location of this thread.
 

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