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Stanford is renowned for its verdant campus, home to a wide variety of flora unmatched by most universities. However, despite its dense population of trees and other plants, the landscape around Stanford is far from natural. Its layout of plant species has been shaped by centuries of human history, and many of the most commonly found trees on campus have origins far from California.

On this walking tour through the Stanford Arboretum, you will see trees that were first planted thousands of miles away from where they currently stand, some more than a century ago. How they arrived here and how they affect the space around them is not always apparent, and this tour seeks to shed some light on the subject. Now, let's go look at some trees!

Our story begins in front of the Anderson Collection, where a 36-foot tall yucca now stands. Native to central Mexico, the yucca filifera is a close cousin of the agave and the Joshua tree. This one in particular is over a century old, and was brought here by Jane Stanford.

This yucca is the first of many non-indigenous trees transplanted from elsewhere in order to display the power and wealth of the Stanford family. Now, walk through the valley of bike racks to the right of the yucca until you reach a street corner with a blue emergency beacon on it.

Once there, go straight ahead and cross the street twice until you arrive at a fork in the road. Take the left path.

Soon you will come across a dirt path on your right - walk down this way.

As you travel through the Arboretum, you may notice many tall trees that look visually similar, with patches of bark in numerous colors. These are eucalyptus trees.

You've probably seen them countless times while walking around campus - Eucalyptus trees number in the hundreds on the Stanford campus, but two centuries ago not a single one existed in all of California. Here's how they got here:

Before shoes and celebrities and smartwatches existed, trees were all the rage in the upper echelon of society. The eucalyptus, first brought from Australia to Europe in 1770 by Captain James Cook, quickly became a hit among the aristocracy due to its "exotic" appearance. Soon everyone and their mother were either buying or selling eucalyptus trees en masse.

By the Gold Rush in 1849, depletion of native trees caused the eucalyptus to become an extremely popular source of fuel. Rapidly increasing demand for firewood meant that eucalyptus trees were highly desirable. Tall and easy to grow, they began to line the streets of California, replacing native species.

Bark strips, the things often seen at the base of a eucalyptus tree, are extremely flammable. California is no stranger to wildfires, and some say that the huge number of eucalyptus trees in the region puts the area at greater risk.

At the end of the dirt path, you will come across a road. Go right on the road until you get to the mausoleum.

To the right of the mausoleum you will see two palm trees of short stature. These hundred year-old trees are Guadalupe palms, endemic to Guadalupe Island, Mexico.

The Guadalupe palm is extremely rare even in its home of Guadalupe Island. The island's large goat population prior to the 21st century prevented new vegetation from growing, gradually thinning the population down to barely over a hundred trees. Thankfully, Stanford has no goats, and these two trees are safe for now.

Once you have finished observing the palms, go back the way you came down the road until you arrive at the Cactus Garden. Make a right once you enter the garden.

Ahead on your right you'll see a massive eucalyptus, and at the center of the garden another tall yucca. The one you saw earlier used to reside here - think for a moment about the amount of resources required to transport such a tree.

At this point in the tour, you will be passing by several large eucalyptus trees. Stanford is home to over 120 species of birds, more than most places in the world. Many of these only exist here due to the resources that these tall trees have to offer.

Here are some species you might see here if you look up. (note: recent studies show that birdwatching is good for mental health)

Red-shouldered hawks in particular are very common in the area due to the abundance of tall eucalyptus trees, where they like to make their nests. Consequently, Great horned owls are also found here as they like to usurp old hawk nests.

Red-shouldered hawk sounds:

Great horned owl sounds:

Closer to the ground, you might see some of these birds. These ones are a bit noisy, and you've no doubt heard them at some point without realizing it.

Western scrub-jay sounds:

White-crowned sparrow sounds:

Mourning dove sounds:

If you're lucky and perceptive, you might spot an Anna's hummingbird flitting around the Cactus Garden.

The numerous hummingbird species present on campus would not be here today if not for the flowering non-native plants such as those in the Cactus Garden and the eucalyptus trees around campus. Once you recognize their song, you'll begin to notice that they are just about everywhere! (however, their small size makes them easy to miss for most people).

Keep an eye out for these and other birds as you continue on the tour!

Keep walking and you will pass by a bench. Right past the bench you will come across a dirt path that may or may not be covered in mud. Traverse it carefully and watch your step. You will pass by more tall Eucalyptus trees - can you spot any birds flying by?

Once you come across a fork in the dirt road, take the left path. Keep walking until you approach the road again, and then walk left alongside it away from the Stanford Hospital. Once you reach a crosswalk, do not cross - instead, make a left to go back down the path that you first walked down.

Continue this way until you reach Palm Drive, and then turn right to walk alongside the palms.

By now you're no doubt accustomed to the 160-odd palms lining Palm Drive, but every day they continue to amaze visitors of the campus. Such was the intention of David Starr Jordan, the first Stanford University president and noted eugenics supporter. The majority of the trees lining Palm Drive are Canary Date Palms, which originate from the Canary Islands.

But have you ever noticed the slender trees that masquerade as Canary Date Palms along Palm Drive? Dotted along the way are ten cliff date palms from the eastern Himalayas. Both varieties of palms are now iconic as gatekeepers to Stanford's campus. but little over a century ago, they existed far, far away in a completely different context.

Make a right on Museum Way and walk through the parking lot until you arrive at the Cantor, flanked on both sides by Canary Date Palms. Hopefully you were able to learn a thing or two about Stanford's non-native trees!