By Brandt Mannchen

For the Sierra Club, when it has outings in Sam Houston National Forest (SHNF), the idea is to have fun, learn about SHNF, find out what you can see, where you can see it, get acquainted with its’ beauty, and determine why it’s important. 

The 163,000 plus acres of SHNF, about 50 miles north of Houston, Texas, extends east to west about 46 miles and north to south about 29 miles.  SHNF is disjunct and split-up into many pieces.  SHNF has a western landscape from Interstate (I) 45 west almost to Richards, Texas; a central landscape from I-45 east to Oakhurst, Texas; and an eastern landscape from Oakhurst, Texas almost to Shepherd, Texas.

In the eastern landscape, there are several native forests, that while having been heavily impacted by humans via logging, road building, farming, ranching, residential development, off-road vehicle use, etc., are fascinating parts of our Southeast Texas geography.

One native forest that I enjoy visiting is the, “Flatwoods Forest Ecosystem”.  This forest exists most prominently in the southeast part of SHNF in the Tarkington Bayou, East Fork of the San Jacinto River, and Winters Bayou Watersheds and the Jayhawker Creek, Blue Branch, and Whiskey Creek tributaries.

The Flatwoods Forest Ecosystem is also found in Trinity River National Wildlife Refuge, Big Thicket National Preserve, and other parts of Southeast Texas.  The U.S. Forest Service, which manages, in trust, SHNF for the public, uses an Ecosystem Classification System (ECS) to guide management.  The ECS refers to the Flatwoods Forest Ecosystem as the “San Jacinto Flatwoods Landtype Association”.

This landtype association is composed of three landtype phases which are:  on Sandy/Loamy Uplands, Willow Oak-Loblolly Pine/Justicia (Water-Willow)-Bignonia (Crossvine) Loamy Seasonally Wet Flatwoods; on Mesic Slopes and Terraces, White Oak-Loblolly Pine/Callicarpa (American Beautyberry) Loamy Mesic Lower Slopes, Mounds, and Terraces; and on Minor Stream Bottoms, Water Oak-Southern Magnolia (Bignonia) Loamy Wet-Mesic Stream Bottoms.  

The key feature of the Flatwoods Forest Ecosystem is its’ poor internal drainage. This forest is found on broad, almost featureless plains, shallow depressions, pimple mounds, and poorly defined drainages.  In this landscape there are few streams, so when it rains, runoff is via overland flow.

A surprise in this wet forest, is that fire plays a more prominent role in shaping this forest than you might expect.  Some parts of the Flatwoods Forest Ecosystem are moist (mesic or intermediate in wetness) to wet most of the time.  In those parts, a variety of bottomland hardwood trees grow, and fire rarely occurs.  But in places where soil dries out part of the year, usually in late Spring, Summer, and early Fall, fire burns and perpetuates a pine dominated forest.  I have seen both hardwood and pine dominated flatwood forests in SHNF.

Some of the trees and other plants that grow in the Flatwoods Forest Ecosystem include:  Laurel Oak, Willow Oak, Loblolly Pine, Longleaf Pine, Water Oak, White Oak, Green Ash, Swamp Chestnut Oak, Red Maple, Sweetbay Magnolia, Swamp Tupelo, Cherrybark Oak, Sweetgum, Southern Magnolia, Southern Red Oak, White Ash, Mockernut Hickory, Bitternut Hickory, Blackgum, American Beech, Dwarf Palmetto, American Holly, Crossvine, American Hornbeam, Eastern Hophornbeam, Winged Elm, Carolina Cherrylaurel, American Beautyberry, Two-Wing Silverbell, Southern Arrowwood, Sweetleaf, Farkleberry, Yaupon, Sebastian-bush, Southern Wax-Myrtle, and Buttonbush.

This is a forest with both open spaces and dense growth which seem to alternate as you walk.  The constantly changing micro-topography provides a challenging hike as you go up and down, through depressions and over mounds, sometimes wet and sometimes dry.  This is a forest that you can literally get lost in but also that provides solitude and quiet.  I enjoy hiking and seeing the small ponds and large hardwood and pine trees in a floodplain-like area.

You can’t beat walking through a flatwoods forest on a crisp, sunny, Winter day.  Try it, you just might become a flatwoods fan like me!