Friday, July 20, 2007

BBNP Photo Report ~ The Cypress-Pine-Oak Woodlands

As I said in my last post, our last day in Big Bend was spent hiking through the park's woodlands. Specifically, we hiked the 14 mile round trip from the Chisos Basin to the South Rim, then back through Boot Canyon and the Pinnicle Trail. This was some hike. We began early, 6 a.m. to avoid as much of the heat of the day as possible. We also wanted to get down from the Pinnicles before any afternoon thunderstorms developed in the High Chisos. Thus it was an intense hike, 14 miles and about a 3,000 foot increase in elevation. It was the first intense hike I've really been on since my friend Jeremy and I did similar increases in elevation and distances in Idaho's Frank Church Wilderness. I was somewhat proud of myself because I was able to do the entire thing at a fairly reasonable pace. I did develope about a dozen blisters ranging in size and severity on my feet and walked gingerly for a few days afterword.

While most of the High Chisos is PJO Woodlands, there are two exceptions in two southeast facing canyons where thunderstorms in the High Chisos are turned by mountains. Both Pine and Boot Canyons can have over 20 inches of rain a year and 100% humidity during the summer monsoons. This situation exists only because of the underlying topography, which causes a unique ecosystem: Cypress-Pine-Oak woodlands. While CPO Woodlands exist further north in both the Guadelupe and Davis Mountains of Texas and further South in higher elevations in Mexico, only Boot and Pine Canyons have this ecosystem in Big Bend. As one hikes from the South Rim to Boot Canyon, the woods change gradually. The first noticible thing is the vairly large presence of ephemeral pools. Some pools were connected by small streams when we were there last month.

Increase in water availability was seen in the plant life. Here are non-cacti succulents, which are certainly not expected in the heart of the Chihuahuan desert.

Also common were ferns, which were also surprising.

The trail from the South Rim gradual descends in elevation along the southeastern side of Emory Peak, the highest point in the park at 7825. Suddenly we found ourselves in the aptly named Boot Canyon.

The dominant tree in Boot Canyon is Arizona Cypress (Cupressus arizonica).

The understory tended to be more lush than the PJO's. Here is a Salvia of some kind.

Chisos Rosewood (Vauquelinia corymbosa) or Slimleaf Vaquelinia, is an attractive evergreen plant. This member of Rosacea is found nowhere else in the world outside the Chisos Mountains.

A common and beautiful grass in these mountains is Feathergrass (Stipa tenuissima). If I was a deer, I think I would prefer this grass over others.

Mountain Sage (Salvia regla) is one of the defining understory shrubs of this ecosystem. Another hummingbird pollenated obligate, blooming coinsides with summer monsoons and the southward migration of the Rufous Hummingbird. Our instructor Dr. Kuban once experienced this event one year in July where thousands of birds arrived in Boot Canyon at once. One can imagine the idea of birds traveling vast distances over deserts between sky islands further north and south, arriving at Boot Canyon to rest, eat the nectar of this plant, and subsequently pollenating it.

Boot Canyon is home to one of my new favorite plants Arbutus xalapensis. This tree is in Ericaceae, a very common family of plants in the Arctic where I have cut my teeth. I would probably really like this tree if it wasn't in that family; it looses it's outer bark and trunk color can vary from cinnimon to red-orange to the color the milk turns after it has been sitting in a bowl with blueberries. It has great evergreen leaves and edible berries. The fact that it is an Erical is an added plus. This shot doesn't give it justice.

Other Oaks occur in the CPO, but the Chisos Red or Grave's Oak (Quercus gravesii) is common in Boot Canyon. This is the only Oak west of the Pecos to put on a spectacular fall display.

In Boot Canyon I saw one familiar face Linum lewisii, or Blue Flax. This perennial is common to most the west and much of Eurasia. I like it's color contrast with Trompetilla in this photo.

Here is a Mountain Mahogany (Cercocarpus montanus) flower. From the Idaho Mahoganys, I would have never guessed that this genus is in the Rose family.

As I said earlier, this ecosystem is wet. Here is Bigtooth Maple (Acer gradidentatum) growing near an ephemeral pool. Bigtooth Maple is very common in the mountain west, and I was happy to see it again.

We saw no large carnivores on our trip. This was the only sign of Ursus americanus. Big Bend's bear population was exterpated earlier this century, and it is believed that they reestablished themselves from populations in Mexico.

Boot Canyon had it's lichens as well. These folios lichens were growing on a dead tree.

I think this is Opuntia phaecantha, or Brown-Spined Pricly Pear. Cacti will grow on dryer exposed surfaces in the CPO Woodlands.

One surprising plants in these woods is Psuedotsuga menzesii, or Douglas Fir. This tree is very common in the mountains of my youth, indeed it was our Christmas tree growing up. Yet here it is in the middle of a sky island in Big Bend.

I spent about two hours in the Cypress-Pine-Oak Woodland of Boot Canyon, most of which was walking. Unfortunately, by the time I got there I'd already walked about nine miles and had five to go. Thus, I didn't have all the time or energy I needed to really see this place. I want to spend a week sometime just camping and exploring here. There is much to see, and it is a truly remarkable ecosystem. I can't wait till I get back.