Trees are marvelous. We love their looks, their smells. We hug them, and watch as squirrels frolic in their branches. We enjoy their shade, and love the sounds of the breeze through the leaves.
But how much do they actually clean the air?
The answer to this depends upon a few factors. How close are the nearest trees? How healthy is the tree? How old is it? And, of course, what type of tree is it?
Dr. Anne Marie Helmenstine published an article with a few handy calculations for us.
- A leafy, mature tree makes as much oxygen as ten humans inhale in a full calendar year
- A leafy, mature tree takes about 48 pounds of carbon dioxide out of the air each year
- An average tree makes almost 260 pounds of oxygen each year
- One hectare of trees (full canopy forest) offsets the energy use of 19 humans each year
- An especially large tree – one that is 100 feet tall, with a base diameter of 18 inches — will produce as much as 6,000 pounds of oxygen
She notes that there are three different ways to look at measuring oxygen production.
- Just looking at photosynthesis, which only happens during daylight hours
- Net oxygen production, meaning the amount made in photosynthesis minus the amount the tree uses (it does use some of its own oxygen)
- Net oxygen production just in terms of the oxygen that would be available for humans to breathe