Research Suggests Ponderosa Pine Trees Hold Their Breath to Avoid Breathing Wildfire Smoke

It seems they don't like breathing smoke anymore than we do

Hiya!

Several years ago, a friend showed me his small bamboo plant and told me it was the only plant he could keep alive — but all I could focus on was the thick layer of dust coating its leaves. Looking at it, my throat tightened like when I walk through a smoke cloud. I quickly and instinctively walked away and returned with a damp cloth to clean the leaves while my friend watched me, understandably perplexed.

“What are you doing?” he asked me.

“Dusting the leaves so the plant can breathe,” I replied.

My friend looked from me to the plant and said, “I never even thought of that.”

Don’t worry. I also adequately praised his bamboo and knew he wouldn’t be offended by me cleaning its leaves. I’m only sharing this memory because it popped into my head several times while writing this article.

With wildfires becoming increasingly common due to human-induced climate change, we’re forced to deal with the smoke that comes with them, which can poison clean air for miles. But while you and I can go indoors and do our best to avoid the toxic air, trees and other plants don’t have the same luxury. Nevertheless, recent and unexpected research found that ponderosa pines still found a way to avoid breathing in wildfire smoke — by holding their breath.

How Plants Breathe

Plants don’t have lungs, mouths, or noses like us, but that doesn’t mean they can’t breathe. Instead, plants have stomata, which are pores on their leaves’ surfaces that function a lot like our mouths.

Both plants and humans (and other breathing lifeforms) inhale chemicals in the air around them and exhale chemicals made within them, including, but not limited to, oxygen and carbon dioxide. Our human chemical exchange is called respiration, but the chemical exchange for plants is called diffusion.

While humans breathe in oxygen and exhale carbon dioxide, plants do the opposite — they breathe in carbon dioxide and exhale oxygen. And while we breathe in and then out, plants inhale and exhale at the same time, simultaneously.

So, what happens when plants are exposed to wildfire smoke? One might assume the plants don’t mind much since they breathe in carbon dioxide, and wildfire smoke has plenty of it. Except, wildfire smoke also has plenty of other pollutants, including particle debris and harmful chemicals like methane and nitrogen oxides, which are poisonous to plants and humans alike.

Wildfire Smoke

The longer and farther wildfire smoke travels, the more sunlight cooks it, changing its chemical composition. Mixing volatile compounds like nitrogen oxide with sunlight creates ground-level ozone, a low-lying layer of thick pollution like smog that can cause breathing problems in humans. But how does it affect plants?