“Plant a tree” seems to be the go-to answer to climate change concerns these days. Booking a rental car online recently, I was asked to check a box to plant a tree to offset my car’s anticipated carbon dioxide emissions. In 2020, the governor of my state, Indiana, launched an initiative to plant a million of them within five years, and the state is a quarter of the way there.
The primary reason for this arboreal zeal is to capitalize on the power of trees to remove excess carbon dioxide from the atmosphere and turn it into wood, safely locking carbon away for decades to centuries.
That’s the theory, anyway.
The problem is that the fate of carbon stored in trees faces many challenges. Heat waves, logging, pests and wildfires can all destroy trees and release that carbon again. And most measurements of the carbon stored in forests’ woody biomass only extend back a few decades.
I lead the PalEON project, an initiative funded by the National Science Foundation that is working to reconstruct how the amount of carbon stored in U.S. trees ebbed and flowed over the past 10,000 years.