re:  Tree Planting Policies vs. Allergies

So after my email last week to the City of Toronto, I was happy to get a number of responses back.  Initially just informing me that they were going to provide me with a proper answer … which was nice, and then eventually the actual answer.

I always knew that this would be a complicated issue and I imagine it is still a complicated issue given that cities are dominated by male trees and you have private property and natural areas to consider as well.  Ultimately, there is no real immediate solution but it is fascinating (and terrifying, not to mention painful) to me the impact a simple decision had on people so many years later.

I’m not one to demand immediate action because I don’t want to see trees cut down but I do appreciate that allergy-sufferers are now being considered in tree-planting policy.  Perhaps in the future, we can hope for fewer allergy sufferers and maybe one day someone like me can enjoy spring without shedding so many tears 🙂

I’m part of the City of Toronto’s tree planting
team (to use the non-technical term). The issue of urban trees and
allergies has been on our radar more and more, and we are developing
strategies to accommodate people who have issues with
pollen. To be clear, or goal is to increase the City’s tree canopy by
putting the right tree in the right place, and part of that is
understanding the needs of the City’s residents.

A small amount of background concerning urban tree
planting: In the 1940s it became increasingly common for cities in North
America to plant male trees as they were considered to be less “messy”
in that they produced little or no fruit
or nut debris which could clutter walkways, etc. Growers began focusing
on male tree stock to fulfill this requirement. As a result, over 60
years later, many cities have a tree population which leans heavily on
the male side. More municipalities are now realizing
the allergy-factor in this type of planting. Added to this,
privately-owned trees and those in naturalized areas are a mixed bag.

There are competing views as to how to tackle this
issue, but a popular theory suggests trees with perfect flowers (as
opposed to dioecious and monecious) are better for people with allergies
as the pollen is potentially more isolated within
the flowers and not wind-carried. For example, a Tuliptree (perfect
flowers) has pollen but it mainly stays within the flower unless
transferred by insects, while an Oak (monecious) relies on the wind to
disperse pollen over a wider distance. At the moment
the only tree widely available that does not produce pollen is Red
Maple ‘Autumn Glory,’ which we plant to accommodate homeowner requests
for allergy reduction.

I hope this answers some questions for you on this
large topic, and indicates that the City is trying to be sensitive to
the needs of allergy sufferers while increasing and diversifying
Toronto’s valuable tree canopy.

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Author: Ehren Cheung

An explorer of life and data. Reluctantly philosophical. A seeker of the ultimate cookie. Another tree-friendly soul with an affinity for hiking and sketching.

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