Self Guided Tour
Areas along the trail are marked with short posts with the area number on top of the post.
Copies of the Tour may be picked up in the Park Office across the street
(Area numbers are noted on the trail map.)
Area 1 Geological History
During the Cretaceous Period, c.135 to 65 million years ago, a warm shallow ocean covered all of the Llano Uplift area, located just north of Fredericksburg, Texas. Fluvial systems were carrying the decomposed granitic sand and gravel to the encroaching shoreline. About 112 million years ago, the sandstone in the outcrop across the creek was deposited in a setting similar to the depositional system working along Live Oak Creek today. Geologists use an old axiom, “the present is the key to the past.” Sands and gravels were deposited in the same environment. There were likely dinosaurs roaming the area. Note the left to right dipping cross beds in the sandstone layers, which indicate that the stream depositing the sand was flowing in the same direction as Live Oak Creek is flowing today. The sandstone is part of the Hensell Formation which serves as an aquifer in the area and also serves as good farm land.
Note the water dripping in the grotto area. This is water leaking from the Hensell aquifer. The drip continues even during dry periods. There are beautiful maiden hair ferns growing along the outcrop. The taller grass-like plants are sedges. Along the creek are a number of water- loving wildflowers, grasses and trees. During floods, the place you are standing might be up to twenty feet under water. When the floods subside plant life continues as before.
Area 2 Live Oak Woods
Trees use shade to reduce the competition from ground cover plants and to reduce potential fuel for wildfires that might destroy them. Here is a small remnant of a live oak forest whose canopy has shaded out most of the light needed to sustain much plant growth at ground level. The small spindly trees are mostly hackberry trees that are desperately trying to reach the sunlight. These hackberry saplings were planted by birds, whose droppings contained live hackberry seeds. There are few grasses or forbs growing in the understory. Keeping out these grasses and forbs limits the potential wildfire fuel; therefore, wildfires had difficulty penetrating the forested areas. This battle for control of territory by trees, grasses and forbs has been waged for many millennia. Trees also defend against fire by growing a thick bark that resists fire damage.
Area 3 Native Prairie
A mixture of grasses and wildflowers, once covered vast areas of Texas, including the Texas Hill Country. Mixed grass prairies were the dominant habitat of the Hill Country prior to European settlement in the mid-nineteenth century. Prairies in this area were more related to savannah habitats where grasslands and mixed woodlands were competing. The prairie grasses contained both tall and short grasses, including big and little bluestem, switchgrass and various gramas. Prairies depend on periodic wildfires to keep the trees from invading their territories. Grasses send down deep root systems to channel water into the sub-stratum, as well as keeping the soil loose, yet free from erosion. Prairies have both grasses and annual and perennial wildflowers, or forbs. Post-settlement land practices did not include periodic burning; therefore; grasslands lost their battle with the invading trees. Today less than one percent of the once vast prairie lands in Texas remain. Notice the harvester ant mound near the trail. Be careful that these ants do not sting you. These ants are in decline in the Hill Country partly because of pressure from imported red fire ants. Unfortunately the Texas Horned Lizard (Horned Toad) is also in decline because the harvester ants are one of this reptile’s favorite food sources. Horned Lizards were once very common in this are amd now are a protected species.
Area 4 Post Oak Savannah
Blackjack and Post oaks are trees that form open forests in higher, dryer sandy areas of the region and state. Upland sandy soil areas are often inhabited by post oak and blackjack trees as you see along this narrow corridor. The open field south of the fence was likely once dominated by these two oaks. Post oaks and blackjacks do not often form dense canopies like live oaks and other riparian trees. Grasses, briars, and low brush can survive in this more open woodland setting. Mature post oaks and blackjacks have thick bark to help them survive wildfires.
Area 5 Cactus and Succulents
Area 6 Geology
Recent sediments of a few to tens of thousands of years directly overlie sediments over 112 million years old creating a gap in the rock record of over 100 million years. The cliff along the edge of the lake is composed of Pleistocene and recent sediments deposited by Live Oak Creek. Buff colored sandy and silty loam deposits overlie a basal conglomerate of pebbles derived from the Cretaceous sediments that are being eroded by Live Oak Creek in its upper reaches. (At one time this area of the lake was part of a gravel pit that supplied road construction materials to the area).
Further down the lake shore (See marker) there is an unconformity surface between the gravel bed and the red claystone. The recent gravel bed sediments are a few to ten thousand years old overlying red claystones of the Hensell Formation which are approximately 112 million years. There was either no deposition of sediments or those sediments that were once here were eroded over time leaving a large time gap in the rock layers.
Area 7 Wildlife
Beavers live in our area and create “hour-glass” shaped marks on trees found near the water’s edge. Beavers made the gnawing marks on the juniper trees. They typically make an hour glass shaped cut on the trees they choose to harvest. They apparently did not realize the wide canopy of the juniper is supported by other trees. Imagine the frustration of having gnawed on a tree and it did not fall. Nutria, which look like beaver, are found in the lake. Nutria have a thin rat-like tail instead of the flat beaver tail. Nutria are exotic mammals introduced into Louisiana for possible fur business. The scheme didn’t work. Now we have nutria spreading across the country.
Area 8 Riparian Habitat
The marshy area below the dam is home for water loving plants, dragonflies, and wading birds.The plants that live in the marshy area below the dam don’t mind wet feet. Sedges and rushes don’t have a problem growing in standing water. Fall aster, wild golden glow, and cardinal flower are wildflowers that prefer moist areas along a creek. Dragonflies and damselflies lay their eggs in the aqueous vegetation along streams like Live Oak Creek. The larvae of these insects can remain in the water for up to several years before emerging as an adult dragonfly or damselfly. In the summer months look for the Green Heron prowling among the plants in search of frogs, crayfish or fish for its next meal. In the winter months another marsh bird, the Sora Rail, lives in thick vegetation and spend their nights hunting for aquatic insects, amphibians and crustaceans. Its distinctive descending whinny call can be easily heard but actually seeing the little marsh-walker is much more difficult. As you walk along the creek edge, always be alert for the many forms of wildlife that depend on the marsh for survival.
Vista Loop and Handicapped Accessible Trail
Area 9 Arid Habitat
Please note the change in vegetation along the face of the slope. The habitat has changed from that across the creek because the soil is mostly clay, drier (above the water table) and well drained. Note the vegetation is dominated by prickly pear, mesquite, and bear grass (Molina), plants that prefer more arid conditions.
Area 10 Cedar brake
Ash juniper is a native plant, but prior to settlement of the Hill Country it was confined to the canyons and steep slopes that protected it from wildfires. As settlers suppressed wildfires, ash juniper spread across the former savannah habitat to dominate the vegetation. Spread mostly by birds dropping seeds beneath trees, ash juniper forms thick, almost impenetrable cover called “cedar brakes.”
Area 11 Bird Blind and Feeding Area
We have identified 178 species of birds in the park. More than 30 species have been seen in this feeding station area, mostly during the winter months. Birds require food, water and cover, all of which are present here. Please see the posted illustrations regarding the feeder types. A dripping water source is an excellent bird attracter. The nearby brush piles provide excellent cover. Look for hummingbirds in the spring and summer months.
Area 12 Butterfly Habitat
We designed our butterfly habitat to provide both larval and nectar plants for butterflies. We have more than 60 butterfly species visiting our habitat. Butterfly adults and larvae prefer native plants. Please note the solitary bee nesting block with many holes for potential egg deposits by female pollinator bees. Please observe without collecting. Also, please stay on the pathways – possible snake habitat.
Area 13 Geology and Rock Exhibition
Some Hill Country rock formations date back for more than one billion years. This exhibit features one specimen from each geological formation in the Hill Country and includes igneous, metamorphic and sedimentary rock types. In the past one billion years this area has featured mountain building periods as well as having been covered by oceans or seas more than once. Please do not deface our rock specimens.
Area 14 Topography of the Hill Country
The Texas Hill Country was formed by erosion rather than uplift. After the retreat of the Cretaceous seas that deposited thick limestone formations, the area was subjected to erosion. Drainage systems set-up by the depression of the Gulf of Mexico slowly worked their way into the limestone layers. More resistant limestone layers formed the “hill tops” as the less resistant clays and marls eroded away around them leaving a topography of mesas and canyons.
The New Pollinator Garden
Area 15 New Pollinator Garden
The New Pollinator Garden is located on the Recreation Loop next to the swimming pool in the Park. Be sure to visit this peaceful garden before completing your visit to the Fredericksburg Nature Center!