[This entry was supposed to be up in the earlier blog but never published because of our problems with Moveable Type.]
30-01-06: Post Oak Savannah
Between the Blackland Prairies and the Pineywoods to the east lies the Post Oak Savannah. For some both form part of the East Texas Forests . But it is useful to distinguish them. Post Oak is a transitional area between the Pineywoods and the Blackland Prairies. Though nine million acres in extent, it is so irregular that not a single county line lies entirely within it . When landscape architect Frederick Law Olmstead (perhaps best-known for designing New York’s Central Park) first encountered Post Oak in a journey through Texas in the 1850s, his description of this region was eloquent: “We came to-day upon the first prairie of any extent, and shortly after crossed the Trinity River. After having been shut in during so many days by dreary winter forests, we were quite exhilarated at coming out upon an open country and a distant view. During the whole day’s ride the soil improved, and the country grew more attractive. Small prairies alternated agreeably with post-oak woods .” Forest, prairie, savanna, and wetlands, all form part of the Post Oak Savannah. The boundary with the Pineywoods is not distinct. Elevation ranges between 300 and 800 feet. Palmetto State Park on the San Marcos River in Gonzales County, where we went last Saturday, lies in the Post Oaks but it is more swamp than savannah. (It was once known as the Ottine Swamp. The name comes from mixing together those of Adolph Otto and his wife Christine, who settled in the area in 1879, establishing a sawmill and a cotton gin around which developed a small community. There are few traces of their original constructions left. The clearly visible “historical” remains in the park date back only to the work of the Civilian Conservation Corps from the 1930s.) Three students were with me, being gradually sold on the project of appraising the status of biodiversity in our region.
The park takes its name from the dwarf palmetto (Sabal minor), one of about thirteen species of palmetto palm found in the “New World.” It is native to the southeastern United States, ranging from Florida to coastal south-eastern Virginia in the north, and west to eastern Oklahoma and eastern Texas. It is one of the most frost tolerant palms, surviving at temperatures as low as -18º C, and thus popular as a garden plant in more frigid regions. Palmetto contains the last major stand before the palm gets restricted to small isolated occurrences further west. The palm is found throughout the park but mainly in an ephemeral swamp—the short Palmetto Trail meanders through this swamp, or at least what is a swamp when there is water. We tried this trail but it was too popular—loud families with children made it a somewhat disturbed experience. It is a carefully engineered trail, designed to make sure that your shoes don’t get dirty—not that there was much chance of that last Saturday. Besides mosses, liverworts, and the ubiquitous epiphytes, the palm was about the only green thing in the wintry brown forests throughout the park. These “lower” plants were a reminder as to how green the place is when there is enough rain. Effects of our ongoing drought were perhaps the most conspicuous feature of Palmetto this time.
The San Marcos River flows through the park, creating much of the wetland habitat that distinguishes Palmetto from the rest of Post Oak. It had rained Friday night and all of Saturday morning before we arrived in the afternoon. These were perfect conditions to enjoy a swamp but the recent drought has been so extreme that there was no real swamp in sight. Palmetto was drier than I had ever seen it before. The river was low, dull brown, and flowing slowly with banks bereft of animal life in the late afternoon. The “long” Naturalist Trail and the shorter River Trail were at least pleasantly muddy. (The “long” trail is barely a mile or so.) These were peaceful, too, and succeeded in inducing the experience of walking through a natural forest though cattle could often be heard in the background. These areas of the park are also reputed to be a paradise for botanists, but botanizing is still something at which I remain inadequate, especially when there are no leaves of inflorescences. We saw plenty of white-tailed deer but, even at dusk, other mammals were rare. There were Northern Cardinals flitting around, their glorious red providing a striking contrast with the deathly brown of the leafless winter forest. (Olmstead’s “dreary forests” come to mind.) Black Vultures were everywhere, eventually forming impressive communal roosts at dusk. We heard American Crows and watched a few soaring hawks. We heard Pileated Woodpeckers on and off throughout the late afternoon but could not spot a single one. The birdlife was strikingly different from that of the more urbanized areas closer to Austin. (More than 240 bird species have been recorded at Palmetto. Birdsong accompanied us throughout our walks.) The vegetation was even more different, but that’s not unexpected. There were much fewer alien species.
Palmetto may well be too user-friendly, perhaps an inevitable consequence of the necessary PR work that Texas Parks and Wildlife must do, especially in a park so close to the powerbrokers of Austin. (The park is barely 55 miles from the city.) There are camp-sites with electricity and there were campers with easy chairs. San Marcos River forms an oxbow lake inside the park but that area has the look of a manicured suburban lawn. (The park is tiny, just about 270 acres. But there are plenty of good forests around Palmetto, and declining towns, should expansion ever become politically feasible.) There are remnants of mudboils around but they don’t boil any more—the last time anyone saw them in their element seems to have been in the 1970s. Palmetto is worth a visit, though perhaps more so in a wetter year, and at a wetter time of year. From our point of view a long-term longitudinal survey of Palmetto would be useful to see whether native species can recover without continued intervention in Post Oak (or at least in Post Oak swamps) when land goes fallow, unlike what we are faced with in the Blackland Prairies.
 Phelan, R. 1976. Texas Wild: The Land Plants, and Animals of the Lone Star State. Excalibur Books.
 Olmstead, F. L. 1987. Journey through Texas, or, A Saddle-Trip on the Southwestern Frontier: With a Statistical Appendix. New York: Sampson, Low, Son & Co.