If you regularly experience hay fever or seasonal allergies, raise your hand (or your tissue)! Alright, now that about [8% of you] have your hands up, use it to pick up some fruit tree seeds and spread them around your city.
If you find yourself with a puffy face and runny nose each spring, you can thank city planners of the past who frequently planted male trees, which produce pollen, and not enough female trees, which receive the pollen. These planners also often planted trees that are pollenated via air currents carrying the pollen vs. via insects.
The result? A bunch of rogue pollen flying around with nothing better to do than irritate your respiratory system.
How we got here
The reasons why city planners started doing this are pretty simple: female trees create fruit and seeds that drop to the ground, and that’s annoying to clean up:
“When used for street plantings only male trees should be selected, to avoid the nuisance from the seed.” 1949 USDA Yearbook of Agriculture
Plus fruit trees often require more water, which some municipalities may not be able to support, and slippery fruit could present a liability for some cities.
Making matters worse, air pollution particles often combine with the excess pollen, which causes the pollen to break apart into smaller pieces. This exposes the pollen grain, which is much more allergenic than the outside of the pollen particle according to The Guardian.
An easy solution
Thankfully the solution to all this is relatively simple: plant a variety of types of trees, including trees that are insect-pollinated since the male trees release less pollen, and more female trees. And with more female trees in urban centers, several needs are taken care of at once:
- Seasonal allergies caused by pollen are greatly reduced.
- More trees means cleaner air, which means less air pollution.
- Improved food security and nutrition in urban centers as free fruit becomes available to residents.
- Greater ground cover can help keep the earth cool and regulate groundwater systems.
- Greater access to greenspace can help city residents feel better mentally, which can reduce difficulties with blood pressure, anxiety, and other ailments aggravated by stress.
Change is underway
Cities are already taking action! While each city has its own main reason for planting trees, one thing is for sure; they’re going to reap all of the above benefits whether they intended to or not.
- Halifax, Edmonton, and Vancouver in Canada have already started planting female trees in order to balance their tree population and reduce allergens. The Guardian
- Philadelphia, USA is planting trees with the goal of achieving 30% ground cover in each neighbourhood by 2025 to improve urban nutrition and quality of life, while also mitigating the effects of climate change. Grist
While some seeming solutions to past urban needs have created new problems for city-dwellers, the good news is that we have the knowledge and solutions to solve them using some of the simplest resources of all: trees!