By Alexandra Pearcy
Looking at a topographic map of Texas, one can see the Coastal Plain of Texas, the land beside the Gulf of Mexico, has some of the lowest elevation of the state. As one travels to the west, elevation steadily increases to 1,000 plus meters above sea level.
This past weekend I had the glory of traveling across Texas, leaving the flat lands of the east side of the state for the hiker’s dream of a graded slope. Although I was not en route to the tallest peak in Texas, I was still on my way to a geological and biological masterpiece, Big Bend National Park.
Even before entering Big Bend National Park, I knew it was about to be an extraordinary experience. Big Bend National Park is located in the southernmost area of the Chihuahuan Desert range in the United States. The meandering Rio Grande River makes the park’s southern border; meaning that in areas of the park by the river you could peer right into the country of Mexico. The elevation of the park, depending on exactly where you are standing, is anywhere from 1,800 feet to 7,800 feet.
The most astonishing feature of Big Bend National Park is the Chisos Mountains. Here elevation is above 5,500 feet with the tallest peak, Emory Peak, being 2,387 meters. In these mountains, you can walk by a prickly pear cactus growing right beside oak and pine trees. The Chisos Mountains are also the only location in the United States where one can find the Weeping Juniper which, like its name, always appears to be drooping but can grow to be 55 feet in height.
The Chihuahuan Desert has elevations around 1,000 to 1,500 meters, making it a high-elevation desert. There, you don’t get many tall luxurious shade-producing trees; instead, you get more scrub and semi-succulent growth due to the high evaporation and low rainfall. With it only raining between 7-12 inches per year and temperatures reaching well above 100 degrees, the desert is the perfect location for Yuccas. Their leaves are quite long and “spine-tipped.”
By the river, at the lowest elevations of the park, you can see the greenery change a bit from the desert flora of the rest of the park. One of the most common plants found in the oasis, so much so that a campground is named after it, is the Cottonwood. These large, fast-growing trees can grow upwards of 6 feet per year. They have leaves that look just like a spade and are 3-5 inches long and they produce a fruit capsule in the summer with silky hairs attached to the seeds.
As you travel throughout the country, or even just the state, take a moment to see if you can distinguish whether elevation is changing and try to observe how plants change through each environment. What do you think allows the change in plants from biome to biome?
Photo by Alex Pearcy: Panorama from Emory Peak in Big Bend National Park in Texas
