Trees: essential for good pasture and livestock performance in South Texas

Summer in South Texas is hot. It isn’t uncommon for us to experience 60 plus days of 100 F degree weather. The unrelenting heat paired with often high humidity makes it a rough climate for livestock. The only relief from this heat is the shade of a big tree and perhaps a nice Southern breeze late in the evening. When most of us think of South Texas we often conjure the image of brush country mixed with native coastal prairie. Much of South Texas is exactly that, but it is also dotted with giant Live Oak trees, bull Mesquites and tall Pecans. These trees in particular as well as many others play a vital role in providing livestock, wildlife and people shade from the harsh summer sun.

The status quo for many years has been to rid your so called “improved” pastures of trees, brush, weeds or quite frankly anything that will compete with the grass. When Mandy and I took over management of the ranch in 2010 we began to let some Mesquite trees grow in our pastures. In our early years of holistic planned grazing I quickly realized that one of our logjams to perfecting our grazing system was shade during the summer months. The issue still isn’t fully resolved, but every year there is a little more shade in our pastures. I am often asked why we don’t use artificial shade? My response has always been two fold. First, we rotate the cattle frequently. Thus, whatever we use must be portable and easy/quick to move. Second, the portable shade structures that are currently on the marketplace are very expensive. In the early years of our operation, that has been entirely financially self-sustaining, we simply didn’t have the cash to spend on luxuries like the Shade Haven. Thankfully we had the foresight from the very beginning to allow trees to grow in our pastures so that one day they would provide shade for our livestock.

Savannas are arguably the most productive ecosystems for livestock and humans. Mark Shepard, author of Restoration Agriculture: Real World Permaculture for Farmers, gives several reasons that savanna biomes are the richest in animal life. “The most significant reason is structure. Imagine a field of trees, brush and grass absorbing sunglight . This structure will absorb significantly more sunlight than just simply a forest or prairie because of it’s depth and textured structure. Not only does this increased surface area absorb more sunligh, but it also increases the surface area exposed to the atmosphere. This simply means more air is taken into the plant, more carbon dioxide is removed from that air and more oxygen is returned. Another benefit of the increased surface area is that more plant surfaces are exposed to rain. The surface area of this structure slows the rainfall instead of allowing it to pound the soil directly. Ultimately this deep, interconnected diversity is what created the deepest, most fertile soils on the entire planet - the breadbasket soils of the Midwestern United States - the temperate, humid savannas of North America.”

The trees incorporated into your farm ecosystem will hopefully provide more than just shade to your livestock. Mesquite trees have a multitude of benefits beyond shade. We harvest trees on our property for Mesquite lumber that wholesales for $6 to $7 per board foot. The wood also makes a fantastic fire wood that is preferred by grilling enthusiasts throughout the world. The beans provide feed to wildlife and livestock alike during the height of the summer when other high energy, high protein sources are scarce. Mesquite beans have likely saved our ranch more than once during severe droughts. The beans can also be ground with a hammer mill to provide flour. The Native Americans knew how valuable this food source was. Brad Lancaster and the Desert Harvesters in Arizona have been harvesting and processing Mesquite beans into a variety of products for many years. Mesquites can be very invasive, but over time I have come to the realization that pasture and ultimately grass management plays an important role in brush/tree encroachment. Imagine your pasture as a solar panel that absorbs all of the light shinning down on Earth. If you leave enough grass and allow it to rest the grasses will thrive. Eventually grasses will make up the majority of cover within your pasture, thus “choking out” the mesquites. It is simply a battle for sun light. This process takes time, especially when pastures have been severely overgrazed and mismanaged. During the transition care must be taken to thin out trees so that it doesn’t one day become a forest.

Live Oak trees are emblematic of the Southern United States. These giant, majestic trees provide the best shade. In addition to their amazing ability to block the sunlight from reaching the ground they provide a bounty of acorns. These acorns are vital to wildlife during the fall season. White-tailed deer often travel long distances to reach a mot of oaks just to gorge on their acorns. The acorns can also be processed to remove the tannins and made into flour. A company named Might Wild in Houston, TX is turning acorn flour into crackers and putting them on Whole Foods shelves. Other folks, such as Acorn Seekers in Flatonia, TX , are finishing the famous Iberico pigs on Live Oak acorns. Care must be taken when stocking cattle in a pasture when acorns are dropping because if consumed in large quantities it can be poisonous. I have only seen it become an issue when there is a lack of other forage such as during drought conditions. Oak also makes a great, mild firewood. Beyond their physical attributes and values, they can bring aesthetic value to the landscape. It’s not uncommon for oak trees to substantially increase the value of real estate.

Some of the most beautiful native pecan groves I have seen are along the creek bottoms of South Texas. Pecans prefer rich, deep soils unlike the Mesquite and Live Oak, which can thrive on the thinnest and poorest of soils. Pecans can play a vital role on some of the most productive landscapes. Creek bottoms and their floodplains grow the best grass for livestock forage. Often these pastures thrive even during the most severe droughts. Because of this flood plains are often cleared of any woody vegetation to make way for grass and livestock. Little do most folks realize that trees play an important role in providing feed for their livestock. Pecans are a fantastic food source for livestock, wildlife and humans. The main trunks of pecan trees are often straight for ten to forty feet making the tree great for furniture and wood floors.

The trees mentioned above aren’t the only species of importance. There are a myriad of others in South Texas. I was helping a friend down the road work cattle yesterday and came upon a Granjenjo (also known as Spiny Hackberry) the size of a tree providing shade in his cattle pens. Its easily the biggest one I have ever seen. Though this particular brush species is detested by most folks, it serves as a great food source for wildlife. It can be invasive and very difficult to remove from pastures and fence lines. It isn’t friendly to your hands and can even puncture the best leather gloves. Yet, these old Granjenjo “trees” in my old friend, Tommy Fillinger’s, cattle pens provide great shade for his livestock.

The reality is that the lack of shade negatively effects animal performance. This can significantly impact your bottom line, especially in predominately hot climates such as South Texas. Researchers at the North Florida Research and Education Center (NFREC) Beef Research Unit decided to conduct a study to evaluate the effect of providing artificial shade for replacement heifers grazing bahiagrass pastures through the summer. A total of 60 black-hided bred replacement heifers, that averaged 920 lbs. of body weight from the NFREC herd were enrolled in the study, which consisted of two treatments: artificial shade versus no shade while heifers were grazing bahiagrass pastures from July 17 to September 2, 2017. Heifers were allocated to each treatment balanced by breed, so that the same amount of Angus and Brangus heifers were in each treatment. Put-and-take heifers were used to maintain the same herbage allowance, thus minimizing any effect of forage availability on average daily gain (ADG). At the beginning and at the end of the study, heifers were weighed on two consecutive days to reduce the effect of gut fill on ADG. A total of 12 pens were used in the study: 6 containing shade and 6 without. Heifers in the shade treatment had one structure per pen with a shade cloth of 36 x 24 feet. During the 47 days of the study, a difference of 0.47 lbs/day in weight gain was observed in the heifers that had shade in their pens, versus heifers in pens without shade.

The message is simple, if you want to improve your pastures and animal performance shade is a necessity. Some folks might argue that artificial, portable shade is the way to go. There is some validity to this argument in regards to nutrient distribution. My counter argument is simply that if you are rotating your cattle frequently (one to three day rotation) with long rest periods what is there to really worry about. They might camp out under a few trees for a brief period of time. Within hours they are moving onto the next pasture. Why not let nature take it’s course and grow a few shade trees?