Ask Dr. Universe: Why do trees grow so slowly?

Dr. Universe: Why do trees grow so slowly? – Ana, 7, Covert, Michigan

Dear Ana,

When you eat food, you get a lot of important nutrients that help you grow taller. Trees that live on our planet also need certain nutrients to grow.

Trees use their leaves to capture energy from the sun to make their own food. But, as you may have noticed, many trees shed their leaves at certain times of the year.

Without leaves, they cannot produce as much food, and without these important nutrients, they cannot grow very fast.

This is what I learned from my friend Tim Kohlhof, a certified arborist and urban horticulture coordinator at Washington State University. He is very curious about the life of trees.

“These trees only produce food part of the year,” he said. Usually we see slower growth of these trees between October and March.

Of course, you might be thinking of the kind of trees that don’t shed their leaves, like pines. When it is really hot or very cold outside, these trees will also experience slower growth. They may be trying to save energy and survive hard times.

For example, in the redwood forests of California, home to some of the tallest trees on our planet, a redwood can grow two or three feet per year.

But if the trees are stressed or don’t have water and sunlight, they might only grow an inch a year. Trees are good enough to adapt to changes in their environment.

Much like humans, many trees that live in forests also grow faster in their younger years. In the forest, it can be a bit of a race to the top. There is a lot of competition between trees to grow tall so that they can get enough sunlight. After all, it is the sunlight that provides them with the energy to prepare their food.

While most humans don’t grow much taller after they reach the age of 18 or 20, some trees can grow to be 100 to 200 years old. A slow growing tree is the magnolia, which can reach heights of around 60 to 80 feet and sometimes even 100 feet tall. These trees can grow about 1 foot per year.

During this time, some trees will grow slowly but may never get very tall. Dogwoods grow only 15 to 20 feet tall and grow about 1 foot per year.

Some trees can grow slowly, but they don’t grow forever. At a certain point, they stop growing and start to gain weight. Not only does the trunk itself widen, but branches also grow around the tree to form its canopy.

You know, we are still learning a lot about how the thousands of tree species grow on our planet. But one thing we do know is that at least for some trees, slow, steady growth is just the right pace.

Truly,

Dr Universe

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