​A  HISTORY  OF  DEGRADATION

​​photo credit: Elizabeth McGreevy

WE USED THE WRONG APPROACH FOR ALMOST 100 YEARS.

WHY?

WE SIMPLY DID NOT UNDERSTAND THE FRAGILITY OF THE KARST BENEATH OUR FEET

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Dr. Peter Ulrich (2002)

"Within karst landscapes…alteration of vegetative communities of any sort can lead to substantial and potentially irreversible impacts on the karst processes."

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UNPROTECTED SOILS LEAD TO DEGRADED KARST  COUNTRY

credit: Elizabeth McGreevy

Dense vegetation cover protects and sustains healthy, sponge-like soils. Healthy soils soak up more rain. More rain in the ground means less surface erosion and downslope flooding. More rain in the ground keeps the vegetation more hydrated to make them more wildfire and drought resistant. Healthy soils have more organic matter and carbon. As more rain enters the ground, it moves carbon deeper into the ground to dissolve more limestone. The more dissolved limestone is, the more porous it is. The more porous, the more groundwater it can hold. It is therefore important to protect and maintain healthy karst country soils. 

MORE ABOUT KARST SOILS

When this region was first settled by Europeans in the mid-1800s, the vegetation was described as a dynamic mosaic that was more than half wooded with the rest being open prairie. The forests were vast, the soils dark, wildlife abundant, and springs flowed year-round. Mountain Cedars (juniper trees that mostly grow on limestone karst country) grew dominated almost half the wooded areas and grew mostly as trees not bushes.

Not understanding the inherent fragility of karst country, European settlers repeatedly burned fields, clearcut hillsides, and overstocked prairies. In the 1890s, the region experienced a prolonged drought. Exposed karst country soils quickly degraded.  When gully-washing rains returned with a vengeance, much soil was lost to erosion. 

Since most Texas karst country could no longer supported dense grass and old-growth forests, pioneering, bushy thickets of Mountain Cedars began to grow where old-growth tree and grass cover was thrived. These thickets were protecting karst country soils from further harm. 

​Yet, in 1939, it was observed that where bushy thickets were removed, springs began to flow. People assumed this meant the trees were bad and so the effort to wipe them out began. In the 1940s, the government paid landowners to clear most of the spreading brush. Doing this led to another mass wave of erosion where we lost an average of 5 inches of topsoil. Although it was clear that continued clearing often led to soil loss, degradation, and flooding, landowners continued to clear out the woody brush since it provided a much-needed, short-term fix: more grass. 

Almost 100 years later, science has proven these limestone junipers are part of the solution to regenerate the soils and limestone porosity of degraded karst country. Clearing them before the land has healed is like ripping off a cast before a bone can heal. For this reason, we need to learn to use them or mimic what they're doing to more effectively regenerate these fragile lands. We need to stop focusing on a species of tree and instead focus on keeping the ground covered, slowing down stormwaters, and reviving soil biology. 

Changing to nature-based solutions will not be easy, but will benefit us all.

credit: Elizabeth McGreevy

Repeating  History

Ignoring the degradation, in 2000, the Texas Water Development Board advised landowners to remove up to 90 percent of their deep-rooted woody brush to benefit cities, industries, and agricultural uses. Landowners received funding to remove more brush. 
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Not the Best Solution

Promoting and funding the focus on woody plant removal on Texas karst country has caused more harm than good.  Landowners are frustrated because they know what they've been doing hasn't been working. ​​

credit: Elizabeth McGreevy

WE NEED TO IMPROVE HOW WE MANAGE

​TEXAS KARST COUNTRY

Although clearing and burning woody brush can work elsewhere, focusing on repeatedly clearing cedar brush can cause more harm than good to Texas karst country.

New research demonstrates how karst vegetation cover interacts with the limestone bedrock. Other studies prove that cedar and other woody brush helps to regenerate degraded Texas karst country, making brush part of the solution. We need to stop fighting cedar brush and learn to work with and mimic what it's doing.

Shifting to nature-base solutions means changing our ways. It will be difficult since clearing cedar brush has become entrenched in our way of life. Landowners are going to need our help.