Overview of Can planting more trees make allergies worse?
This NPR Short Wave episode looks at a surprising tradeoff in urban forestry: while trees improve air quality, cool cities, and support wellbeing, they can also worsen allergies and asthma for some people. The episode explains how pollen exposure, climate change, and tree selection all affect respiratory health—and why planting more trees is not automatically good for everyone.
Key Takeaways
- Trees provide major public benefits:
- shade and cooling
- cleaner air
- stormwater management
- habitat and overall quality of life in cities
- But tree pollen can trigger:
- allergic reactions
- asthma flare-ups
- coughing, wheezing, chest tightness
- Climate change may be making pollen problems worse by:
- extending pollen seasons
- causing plants to bloom earlier
- increasing pollen production in some species
- The solution is not “fewer trees,” but better-planned tree cover.
What the Episode Explores
The personal angle
Host Nate Rott and producer Juan Diego Ramirez discuss how pollen can be a real health burden, especially for people with asthma. Ramirez shares his own experience with severe symptoms after moving to a new region and dealing with unfamiliar pollen.
The science behind the problem
Experts explain that pollen allergies are becoming more of a challenge because:
- warmer temperatures can lengthen allergy seasons
- higher carbon dioxide levels can increase pollen production
- pollution can interact with pollen and make it more irritating or allergenic
Tom Ogren, a horticulturist, argues that this creates a “perfect storm” for people with pollen sensitivity.
Research Highlight
The episode cites a 2013 study in Environmental Health Perspectives led by epidemiologist Gina Lovasi of Drexel University.
What the study found
- Children living in areas with more tree canopy early in life were more likely to show allergic sensitization to tree pollen.
- In the study:
- the group with the least tree cover near birth had 12% sensitization
- the group with the most tree cover had 26% sensitization
Important nuance
This does not mean trees are bad overall. It means early and frequent exposure to certain pollen sources may raise allergy risk for some people, even while trees provide many other health and environmental benefits.
Practical Advice for Allergy Sufferers
Dr. Jay Portnoy, an allergist at Children’s Mercy Hospital, offers tips for managing pollen exposure:
- Track local pollen seasons where you live
- Keep windows closed during high-pollen periods
- Drive with windows up when pollen counts are high
- Shower after being outdoors to avoid bringing pollen inside
- Use an air purifier indoors
- Check daily pollen counts before going outside
The episode also notes that pollen seasons vary by region and by plant type, so what’s true in one city may not apply in another.
Urban Planning and Policy Implications
A major message of the episode is that tree planting should be done more thoughtfully.
Why tree variety matters
- If a neighborhood is dominated by one type of tree, its pollen can be overwhelming during that species’ bloom season.
- Planting a diverse mix of trees can reduce the burden from any one pollen source.
Who makes the decisions
This is often beyond the control of individual residents. The episode argues that:
- city planners
- policymakers
- urban forestry leaders
should consider allergy impacts when designing greener cities.
Main Conclusion
The episode’s central point is that more trees can be both a benefit and a burden. Urban forests are still essential for climate, health, and livability—but communities should plant them strategically, with pollen diversity and public health in mind.
Notable Insight
“We need trees—but we need to think about what kinds of trees we’re planting.”
That idea sums up the episode well: the goal is not to choose between healthy cities and healthy airways, but to design urban green spaces that support both.