Maximum Tree Height

The tallest trees in the world are Coast Redwoods. The highest known specimen is named Hyperion and is located somewhere in Redwood National Park in California. Its exact location is a well-guarded secret to protect it from potential damage. One day, I’m sure, we’ll explore this grand tree in its own article, but recently I came across an interesting study about the theoretical side of tree verticality.

Hyperion is documented to top off at 380.3 feet. But how high could she hypothetically grow?

Humans are notoriously bad at estimating height. Ask someone how tall the tree is in their yard or in the park and, chances are, the answer will be significantly erroneous. In the past, people have claimed some trees to be 430 feet high or even 490 feet. These days, we have lasers and extremely long tape drops to improve the accuracy of measurements.

Plants use photosynthesis to live and grow, which means they have a special relationship with the sun. If the neighboring plants are all higher than a specimen, it will receive less life-giving energy, so you’ll often see plants and trees shooting upward to grab the prime sunny-day real estate. There is an incentive to be tall.

But trees aren’t infinitely tall. There is another factor at play when it comes to height: gravity.

Florae also need water to survive. For some plants, pushing water against gravity to all their extremities is no problem, but lifting liquid nearly 400 feet above the surface of the earth is no joke.

It is ultimately this game between gravity and sunlight that determines the theoretical maximum height of trees, according to George Koch of Northern Arizona University. He and a team conducted studies on Redwoods and discovered that the leaves at the tops of the trees essentially live in “constant drought” because of how hard it is to transport water to them.

According to their study in Nature, for California Redwoods the “tug of gravity and the friction between the water and the vessels through which it flows mean that fluid cannot be dragged any higher than 122-130 meters.”

For us, plebians, in the United States, that’s between 400 and 426 feet.

So even the tallest known tree is only about 89% of the way to the theoretical maximum.

Lest you think Hyperion and other redwoods are slacking, other real-world factors might keep the trees from nearing the upper bound. Wind damage can wreak particular havoc to delicate portions in the upper canopy. Drought at soil level can stunt growth. Over potential lifespans of thousands of years, these trees endure quite a bit.

While we know a tree might never be able to push past 426 feet on Earth, what about a redwood growing in the zero-gravity of space? Could a tree grow infinitely tall? I’ll get an email into George Koch at Northern Arizona University. I’m sure he’ll humor me.