Nehaveigur

Why does California have the tallest, biggest and oldest trees?

Coastal redwoods (Sequoia sempervirens) are the tallest trees on Earth, reaching 116 meters. Their range is coastal Northern California.

Giant redwoods (Sequoiadendron giganteum) are the most massive trees on Earth, reaching 1,487 cubic meters. Their range is the Western slope of the Sierra Nevada.

Bristlecone pines (Pinus longaeva) are the oldest trees on Earth, reaching 4,856 years. Their range is the Eastern slope of the Sierra Nevada, where the oldest specimen is found, Nevada and Utah.

How come California is home to three species of trees that represent three different superlatives?

One explanation could be that they’re all relatively closely related to each other, and that we’re only looking at one superlative with three different manifestations. After all, it takes time to grow tall, and growing tall and massive are quite similar. So maybe the three superlatives are really just one?

This isn’t the case. The two species of redwood are in a different genus, meaning that they diverged a long time ago. Although they’re both each others’ closest living relatives, they have multiple extinct relatives in different parts of the world. Their closest living relative, the dawn redwood (Metasequoia glyptostroboides), is found in China and isn’t as tall or massive. Bristlecone pines and the two redwood species are even more distantly related, clearly representing a distinct superlative.

Another explanation could be that there’s something about the climate in California that is favorable to trees that grow old, tall and massive. This isn’t the case either, since all three trees grow in different climates (coastal, the relatively humid Sierra Nevada west slope and the relatively dry Sierra Nevada east slope). Neither is any of the three climates unique to California, so why aren’t superlative trees found in those other places with comparable climate?

The answer is related to the history of California. Few places have seen such a short time between the advent of large-scale logging and the official protection of its trees. Logging in California started with the Gold Rush in 1848. Yosemite became a National Park  only 42 years later, in 1890, with other parts of the Sierra Nevada where redwoods are found following shortly thereafter. In other parts of the world such as in Europe, logging has occurred for 100s of years, so that no trees have had a chance to grow old and tall. In some places such as Iceland or the Easter Islands, no trees are left at all.

For this to be a convincing explanation, it’d be necessary to first show that there were trees in other parts of the world that were similarly tall than the redwoods or similarly old than bristlecone pines, but which have disappeared to human interference. This seems to be the case, with the tallest tress ever being a Douglas fir (Pseudotsuga menziesii) that measured 142 meters when it was felled in Washington State in 1897.