How Tall Can A Tree Be?

Have you done the tourist thing and tipped your neck way back to look up at the skyscrapers in New York? Have you looked up the trunk of a tree? They’re pretty impressive, too, but it seems they can only grow so high.

Trees are like us: we’re both systems. Blood in our bodies moves nutrients to our cells and removes waste. Sap does this in trees. Phloem sap contains sugars that the tree produces in its leaves as its converts sunlight during photosynthesis. This flows down the tree. Xylem sap contains nutrients that the tree needs to grow, again like our bodies (both of us need calcium but for different reasons). Xylem sap moves up a tree to make sure it has what it needs to live and grow.

Gravity only works in one direction. So, Xylem sap has to rely on forces to make it journey, including the fact that leaves take in carbon dioxide and give off oxygen. As they breathe, they give off water (transpiration), which creates enough negative pressure to pull xylem sap up the trunk. A little something called capillary action helps the vertical journey as does root pressure, or the pressure created at the tree’s base where phloem sap and xylem sap meet and exchange water through something called osmosis.

We’ve found a cool video that describes the process here.

Still, gravity is a law and laws must be obeyed. So, trees can only reach certain heights because this really cool system can only bring water and nutrients so far. The name for this is the hydraulic limitation hypothesis. Kind of amazing when you stop to look at some of the trees in Connecticut, which were around well before a lot of landmarks we take for granted like I-84, the beautiful Saville Dam, or even the whaling concerns showcased in Mystic, which used tall trees to build ships strong enough to weather the long ocean voyages.

Naturalists Chris Atkins and Michael Taylor measured what they believe is the tallest tree in Redwood National and State Parks in Northern California, claiming it stands at 380 feet. (They climbed it to take the measurement. People who love trees often love climbing, too.) The General Sherman Tree in Sequoia National Park is recorded as the world’s largest by volume and 275 feet in height.

OK, the Empire State Building does dwarf that, standing 1,454 feet at the tip. But, as far as living things goes, a tree is pretty cool and you don’t have to be a professional arborist providing tree services to think that.