December 17, 2010

Big Thicket National Preserve, near Beaumont, Texas

Located in eastern Texas just north of Beaumont is the Big Thicket National Preserve. Set aside in 1974, it was the first national preserve in the nation, protecting 97,000 acres of diverse ecosystems. Big Thicket is at the crossroads of several major biomes including the cypress/tupelo swamps of the south, the prairies of the Great Plains, the deciduous broadleaf forests of the north, and the Chihuahuan desert of the southwest.

The "slope forest" with beech, gum, and hornbeam, among others.

The Big Thicket is the name for a region roughly 2 million acres in size ranging from the outskirts of Houston north to Nagodoches and east to the Louisiana border. But, timber harvests, agriculture, and later urban development have dissected and isolated the ecological units of the region until they became tiny islands and slivers of land in a sea of human alteration.

A loblolly pine intermixed with various deciduous trees

It was a landscape rich in game and food where people lived off the land away from civilization. In fact, it was one of the major hide outs for people trying to escape the ravages of the civil war. But, by the 1960's there was almost nothing of the natural ecosystems and processes left after the region had been clear-cut, plowed under for agriculture, and then slowly built up for housing. Finally, local citizens began to unite to try and save the last remnants of this landscape. Through a combination of purchases by conservation organizations and donations by local land owners, the Big Thicket National Preserve was pieced together and then set aside by Congress to be managed by the National Park Service.

A satellite photo of the big Thicket region.
The dark green strips following the rivers are the protected units.

I actually visited the Big Thicket with Samy back in October 1998. At the time, we hiked the 3-mile Kirby Nature Trail that travels across several distinct ecological units that range just a few feet in elevation apart.  Upon returning in early December 2010, I decided to take Linda and Hilina on the same nature trail.

Elevation changes of just a few feet make such dramatic changes in the ecoystem type, because the water table is so close to the surface and the soils are well-drained sandy materials. So, if you are in the lowest levels where the roots of trees are constantly below the water table, you get a cypress-tupelo swamp, much like you would see in Louisiana or other parts of the Deep South.

Interestingly, the area has been in a drought this fall and so the water table has fallen significantly since when I saw it in 1998. As such, the cypress were not sitting in standing water, but completely exposed on dry land. Compare these pictures between between October 1998 and December 2010 taken at the exactly same spot to compare the difference. Notice the slightly tilted large tree at the left as your comparison.

October 1998

December 2010

A few feet higher, where conditions remain wet, but the roots are not inundated with standing water, are the acidic baygalls containing broadleaf evergreens including laurel, hollies, wax myrtle, sweet bay, and magnolias.

American Holly

My buddy Samy examining the baygall forest back in 1998

Just above the baygall is the slope forest, containing deciduous broadleafs including American beech, hickory, gum, and hophornbeams.  This forest type is high enough to be out of the water-logged soils, but has soils compact enough to retain water reasonably well. This attribute allows tree species that require summer soil moisture, like deciduous trees the opportunity to dominate.

Linda and Hilina going from magnolia dominated baygalls into slope forests

At the highest elevations are the sandy soils dominated by longleaf pines. Sand actually dominates the entire landscape. Since sand drains moisture so well, even such a humid and wet environment such as this can be nearly desert like. Thus, in addition to drought tolerant pines species you can find prairie grasses and desert plants such as various species of cactus native to the Chihuahuan desert.

Longleaf pines growing on sandy hills with prairie grasses and scrub oaks

The acidity of the soils also plays a major role in species composition. In boggy areas too acidic for the swamp species, you will find carnivorous plants such as these pitcher plants below. The area also has tiny sundews. Carnivorous plants, contrary to popular opinion, do not get their "energy" from the insects they consume, but from photosynthesis from the sun. But, if the soils are too acidic, it prevents the uptake of nutrients from the soil. So, carnivorous plants get the necessary minerals and nutrients from the insects instead.

Pitcher plants in the bog

I mentioned earlier how the drought dramatically changed the appearance of the Kirby Nature Trail. But, that was not all. As I hiked the trail, I told Linda, I feel like I don't remember this place. I know it has been 12 years, but seriously, my photographic memory is pretty good in situations like this and it just seemed totally different. Well, there was more at play than just the water table. But, before I get to that, see one more comparison shot from 1998 to 2010.

A swollen and muddy Village Creek in 1998

An almost empty and clear Village Creek in 2010

Being that it was early December, rather than late October, meant that the deciduous trees were more advanced on dropping their leaves this time. That resulted in a more open canopy, rather than the closed dark forest I remembered. But, as it turns out, there was something much more important at play.  In 2008, Hurricane Ike dramatically changed the landscape. What was once a dark forest is opened by because so many trees were toppled. Everywhere you look you see trees uprooted and on the ground or standing trees ripped of their tops and branches.

Large bald cypress with their tops blown off
A number of trees stripped of their branches and killed

A toppled and uprooted tree

Big Thicket National Preserve has a whole number of units. But, the Kirby Nature Trail is an excellent introductory route to take because it is close to the brand new Big Thicket Visitor Center (which did not exist in 1998) and has an interpretive booklet you can read along the way. Another unit I highly recommend when you are in the area is to take the 1-mile Sundew Loop, which is a boardwalk through pine forests and pitcher plant bogs located just up the road from the visitor center.
Samy on the Sundew Loop boardwalk

The other place to check out is the Roy Larsen Sandyland Sanctuary. It is a Nature Conservancy preserve right in the middle of the Big Thicket that preserves a series of sand dunes that contain a long-leaf pine forest. Long-leaf pines were once one of the most important trees speciesa of the southeastern United States until agriculture, fire supression, and forest management practices greatly reduced its abundance. So, to go to this preserve gives an excellent opportunity to see what this forest is like. We did not go there this time due to other committments, but I did hike there in 1998 and enjoyed it a lot.

1 comment:

Lisa Richardson said...

Glad you enjoyed your visit. Great overview of history and characteristics. Enjoyed the comparison photos! I've never seen anything like the drought we're in this year. Happy trails to you!