Overview / Resources

  • Entrance to CBFS
  • CBFS Pasture
  • CBFS Lab
  • Tree Frog
  • CBFS Students


The Center for Biological Field Studies (CBFS) is located in Walker County, Texas, approximately three miles northeast of Huntsville (seven miles from the Sam Houston State University campus) and adjacent to Sam Houston National Forest to the east and to the south. The property is roughly rectangular (678m x 1593m, maximum width and length), with the length oriented north/south. Covering 100 hectares (247 acres), CBFS is centered on 30.743000ᵒN, 95.473000ᵒW. Flowing from south to north, Harmon Creek’s course bisects the station at about 220 feet. above sea level. From the creek basin the landscape rises rather abruptly to low rolling hills, reaching 300 feet.

Map of CBFS (PDF)


The Center for Biological Field Studies is in the subtropical belt characterized by high humidity and abundant rainfall, resulting from the moist air moving inland from the Gulf of Mexico. Winters are mild, summers are usually hot and humid. Annual climate averages are: rainfall 46.7 inches, snowfall 0.6 inches, precipitation days 93, sunny days 204, July high temperature 94ᵒF, January low temperature 39.2ᵒF.


The soils on the west side of the creek are Depcor-Huntsburg association; highly acidic, with a thin layer of sandy loam covering a deep mixture of variously colored heavy clays. The berms and bottoms of some of the old fish hatchery pond sites are Houston Black clay; a very firm, moderately alkaline, black clay. The creek basin consists of Kanebreak soils; neutral fine sandy loams.  On the east side of the creek the Depcor-Huntsburg clay is crested on ridgetops and knolls with Gunter soil; a very friable, strongly acid, dark grayish brown loamy sand about 4 inches thick. In contrast, on the east side, there are also two plots, of Ferris clay; a moderately alkaline gray clay. The parent material for the Depcor-Huntsburg and Kanebreak soils is terrace of beach deposits of non-calcareous, unconsolidated material and for Ferris and Houston clay the soils formed in calcareous, clayey sediments. (USDA.  Soil Survey of Walker County, Texas. 1979.)


The headwaters of Harmon Creek are seven spring fed ponds approximately 4 km (2.49 mi) south of CBFS, along the north side of US 190 just west of Thompson Road, 30ᵒ42’30”N, 95ᵒ27’30”W. They flow generally north form a substantial east/west-tending upland divide which separates the Trinity River drainage to the north and the San Jacinto River drainage to the south. The creek flows north for sixteen miles to its mouth on Lake Livingston, near the Trinity County line (at 30ᵒ52’N. 95ᵒ24’ W).

Harmon CreekAlong its course the creek picks up additional flow from other creeks, such as the East Fork of Harmon Creek, Wynne Creek, Ford Branch, Spring Creek, Parker Creek, and Cedar Creek. Harmon and Wynne Creeks are perennial streams that flow together within the boundaries of CBFS just south of the old dam, creating a substantial flow of water.  The normal mean depth is 15 cm and the mean width is 4 m.

The water is clear with a sandy substrate. There are several stretches of riffles within the creek’s course through the field station.

In 2009, an intermittent stream bed was redirected to bring runoff from the west into two of the former hatchery pond sites. The total surface area is about 3.5 acres. The bottoms slope from west (ca. 20 cm deep) to east (ca. 200 cm deep) when the ponds are full. Typically the ponds fill in the winter and recede in the summer to less than half of their full capacity. Several of the surrounding pond sites also hold water for several to months after a heavy rain period. None of these ponds have fish and are important breeding sites for anurans at the field station. They have also been used as nursery sites by beavers and river otters in recent years.

Additionally, there are a number of ephemeral pools scattered about the forest. Current management plans include adding to this number in a diversity of habitats.


The site is in the southwest corner of the Pineywoods vegetational area of East Texas, which supports 1792 species of plants. It is also only 10 miles northeast of the extent of the Fayette Prairie (Blackland Prairie vegetational area, 1552 species).  “Pineywoods” is a very general term and encompasses forests that are dominated by Longleaf Pine, Pinus palustris, Shortleaf Pine, P. echinata, and Loblolly Pine, P. taeda.  Embedded among all of these pines are patches of hardwoods of various composition that totally lack pines, especially in riparian areas.  To the west, the Pineywoods has an irregular boundary with Post Oak Savannah and Blackland Prairie, and to the south with the Coastal Prairie.  Almost the entire area was clear-cut between 1900 and 1940, and certainly what has grown back is a poor representation of what was there before.  A mixture of land use and management practices over the complete temporal scale has also contributed to the current heterogeneity. 

CBFS floraThe flora of the Center for Biological Field Studies is a mosaic of such patches strongly influenced by anthropogenic factors, a variety of disturbances and a mix of soil types and topography.  We are currently working to identify and map the various floral assemblages and inventory the species present.  There are stands of relatively old Shortleaf Pine, P. echinata, which once had a savannah understory that has now yielded to a dense midstory due to fire suppression. Work is underway to restore some of this pine-savannah habitat.  Much of the forest is covered in dense stands of immature Loblolly Pine, with a carpet of pine needles and scattered Yaupon Holly, Ilex voitoria, and SweetGum, Liquidambar styraciflua.  The area that was a lake in 1977 is now a stand of Box Elder, Acer negundo, and White Ash, Fraxinus americana, shading a sea of Broadleaf Woodoats, Chasmanthium latifolium.  Along Harmon Creek, Sycamore, Plantanus occidentalis, dominates a more complex community that is currently being influenced strongly by beavers.  Near the center of the property there is a good representative stand of Bottomland Hardwood forest with a nearly closed canopy of Water Oak, Quercus nigra.  Also along the creek the historic Cane Breaks, Arundinaria gigantean, are returning.  The Houston black clay in some of the hatchery pond sites is home to a diversity of Blackland Prairie species.  The Ferris clay soils support a different assemblage of prairie plants as well as a unique patch that is dominated by elm, Ulmus sp., hackberry, Celtis sp. and Bois d’arc, Maclura pomifera, with Dwarf Palmetto, Sabal minor, prominent in the understory.

When the fish hatchery was operational, there were 39 ponds, occupying 15.2 ha (37.5 acres).  This area was free of trees and the berms that divided the ponds were mowed regularly, as was approximately 30 acres more, which was part of the support facility.  Less than five acres of this is now maintained as lawns.  A five-foot-wide path on the top of the berms is mowed regularly to provide access.  The rest has been allowed to return to forest. Interestingly, each pond regenerated differently and there are stark contrasts between many of them. Work has just begun to quantify this diversity.

Much of the forest has a significant accumulation of course woody debris.  There are also numerous deeply eroded gullies and steep banks associated with the creek.  All of this provides an abundance of microhabitat for non-vascular plants and fungi.



The Center for Biological Field Studies has a complement of infrastructure and equipment to support the efforts of researchers working at the station.

Our weather monitoring array includes three Davis Instruments, Inc., Vantage Pro 2 weather stations and four leaf wetness, soil temperature/moisture monitoring stations, logging climate data 24 hours a day.

The Net House (below) is a small (600-square-foot) field laboratory. It holds a growing collection of field equipment, has fiber optic internet and wireless internet access, and plenty or work space.

Net House

The building has heat and air conditioning, a complete kitchen, two twin beds, and a bathroom with a shower. There is no fee for staying there but guests are asked to provide their own lines and to clean up after themselves.

There are two 30’ x 60’ greenhouses on the property. Greenhouse #1 has automated heat, ventilation, and drip irrigation equipment. Greenhouse #2 has an evaporative cooling system but no heat.

The Pineywoods Environmental Sciences Lab is an 1800 ft. sq. building that provides a teaching lab, classroom, and meeting space. It has a food preparation and serving area, and a restroom.

The Aquatics Facility offers -?

The Fry Shed is a tin roofed pavilion that was once home for the fish hatchery’s hatchlings.  The fry were reared in 10 3’ x 20’ concrete troughs, which now provide excellent enclosures for behavioral studies with small animals.  Lighting and freshwater are available.

There are 6.1 km (3.8 mi) of trails accessing the historic hatchery pond sites, suitable for walking or hauling equipment on the station’s ATV. The more pristine areas of the forest can be reached on foot via the 5.7 km (3.6 mi) interpretive hiking trail. The Bearkat Forest Trail has interpretive signs, park benches, for resting and observing wildlife, and picnic tables for workstations.

With the Sam Houston State University [link] campus only a few miles away, researchers working at CBFS have ready access to the Texas Research Institute for Environmental Studies (TRIES) [link] and its analytical lab, the SHSU Museum of Natural History, Newton Gresham Library [link], and the University Hotel [link].

The Center for Biological Field Studies is a convenient base for field studies extending into the greater landscape. The 163,037 acre Sam Houston National Forest is next door. Sam Houston State Park, the Lower Trinity River, Lake Livingston and Lake Conroe are all only a few minutes away. The Big Thicket National Preserve, Davy Crocket National Forest, Angelina National Forest - Trinity River, Attwater Prairie Chicken, Texas Point, McFaddin, Anahuac, and Brazoria National Wildlife Refuges - I.D Fairchild, Masterson, E.O. Sieclce, John Henry Kirby Memorial, and W. Goodrich Jones State Forests - Alabama Creek, Alazan Bayou, Bannister, Angelina-Neches/Dam B, East Texas Conservation Center, and Sam Houston National Forest State Wildlife Management Areas - are all less than a three-hour commute from CBFS.