Oak Trees Have a Secret: They Keep Breathing Even After They Stop Growing!
Quick Summary
Scientists have discovered something surprising about oak trees: they keep absorbing carbon dioxide from the air for months after they have stopped growing for the year. This challenges what scientists thought they knew about forests and climate change. The study was published in the journal Science Advances.
What Happened?
Here is something most people don’t think about: when you breathe in and out, your body is doing two things — taking in oxygen and growing. But what if those two things could happen at different times? That’s basically what scientists just discovered about oak trees.
Researchers from Columbia University studied oak trees at 137 locations across the eastern United States and California. They combined satellite images, tiny sensors attached to tree trunks, and carbon dioxide monitors up in the treetops. They even used tree ring records going back to 1950.
What they found surprised everyone. Oak trees in the eastern US generally grow their new wood between May and July. Then the growing stops. But the trees keep soaking up carbon dioxide from the air — right through October! That is more than three extra months of “breathing” without any growth.
In fact, about 36 out of every 100 units of carbon the eastern trees absorbed in a year came in after their growth had already ended for the season.
Why does this happen? Growing new wood actually requires water pressure inside the tree — kind of like a water balloon that needs to be full before it can expand. In late summer, when things get drier, the tree can’t grow anymore. But its leaves are still green and full of sunlight. So the tree keeps doing photosynthesis — it just uses that energy in other ways instead of building new wood.
Why Does It Matter?
Forests are one of Earth’s most important tools against climate change. Trees absorb carbon dioxide — the gas that traps heat — and lock it away inside their wood. Many scientists and computer models have assumed that if a tree is absorbing more carbon dioxide, it must also be growing more wood.
But this new discovery shows that is not always true. Some of that extra carbon the tree absorbs goes into leaves and other short-lived parts — not long-term wood storage. This means scientists may need to update their climate predictions about how much carbon forests can actually hold onto in a warming world.
It is not scary news — it is important, useful news. The more accurately scientists understand forests, the better they can plan ways to protect our planet.
Big Words
- Photosynthesis — the process plants use to turn sunlight, water, and carbon dioxide into food and oxygen; think of it as a plant’s way of “eating” light
- Carbon dioxide — a gas in the air (written as CO₂) that humans and animals breathe out; plants absorb it, and too much of it in the atmosphere traps heat and warms the planet
- Carbon storage — when carbon from the air gets locked away inside trees, soil, or rock so it can’t warm the atmosphere; like putting CO₂ in a long-term safe
- Tree ring — a thin ring of wood a tree adds each year as it grows; scientists can count them like birthday candles to learn about a tree’s history
- Climate model — a powerful computer program that scientists use to predict how Earth’s temperature and weather might change over many years
Fun Fact
The oldest living oak trees in the world are over 1,000 years old. Some have grown so slowly that their trunks are less than three feet wide — proving that slow and steady can still make a giant!
Think About It
If trees are absorbing carbon for months longer than scientists thought, what other secrets do you think forests might still be hiding?
Sources
- ScienceDaily / Columbia University Lamont-Doherty Earth Observatory — Trees keep absorbing carbon long after they stop growing
- Missoula Current — Scientists rethink how much carbon forests can store
- SciTechDaily — Climate Models May Be Wrong About How Trees Store Carbon