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Hill Country Browse

Hill Country Browse

Article and photos by Steve Nelle (except where noted)

 

The Texas Hill Country has the highest density of shrub-eating animals in the United States.

Texas is home to about 4 million white-tailed deer, and about half of them live in the Hill Country and Edwards Plateau. In addition, Texas is home to more than 2 million goats, sheep and exotics, and the majority of these live in the Hill Country. These animals depend on browse, the leaves and tender twigs of woody plants, as an important part of their diet.

There are about 200 species of woody plants native to the Hill Country and an average ranch may have 30 – 60 different types. Knowing how to identify, appreciate and manage browse plants is one of the primary jobs of successful ranchers and wildlife managers.

Scientific studies have revealed the importance of browse in the diet of small ungulates, and when it comes to white-tailed deer, browse is the primary part of their diet. Deer also eat mast, forbs and some grass, but browse is what keeps them alive most of the time. Table 1 shows the percentage of browse in the diet of deer, livestock and common exotics based on studies done at the Kerr Wildlife Management Area.

 Photo by Wyman Meinzer

 

Nutritional Value

The nutritional value of browse ranges from poor to exceptionally good. While there is considerable variation from species to species, the greatest variation is from season to season within a given species. For example, the new spring growth of hackberry contains 25 percent crude protein with high energy value while the old leaves of summer have only 8 percent protein and low energy value. Table 2 lists seasonal protein and energy values of some common Hill Country browse plants.

Most of the region’s browse plants are deciduous, losing their leaves in December and remaining bare until April. During this four-or-five-month period the browse supply is diminished greatly, and this can be a critical time for deer, especially in a dry winter. Fortunately, a handful of browse plants are evergreen containing “antifreeze” compounds in their sap which allows green leaves to persist through winter. Table 3 lists the most important evergreen browse species and their wintertime nutritional quality.

Although the nutritional value of most winter browse is low, remember that deer have reduced nutritional needs in the winter. Bucks are not growing antlers and does are not lactating, so they can survive on lower quality browse.

Another form of winter browse—fallen leaves—are not well understood; and these can provide significant nutrition. Fallen mesquite leaves are often eaten and contain 16 percent protein, although they are low in energy.

 

Browse Preference

Not all browse is created equal and browsing animals are selective about what they consume. With agile lips and prehensile tongues, they can select the individual leaves they prefer. Selectivity and preference is driven by tenderness, nutritional value, taste and the presence of spines or thorns.

New growth is preferred over old growth since it is more tender and nutritious. Older mature leaves are higher in lignin which reduces digestibility, quality and palatability. Think of the difference in eating a young tender pod of okra compared to an old, tough pod. The difference is lignin and the same thing happens with browsers as they seek plants that are most tender and digestible.

Browsing animals have a good sense of nutritional wisdom, consuming plants that will best meet their nutritional needs for energy, protein and minerals. They “know” which plants are more nutritious and which are less nutritious. Given a choice, they will select the most nutritious diet possible from the plants available in the pasture. However, on overpopulated or degraded ranges with poor plant diversity, they are not able to exercise much selectivity because they do not have much to choose from and must eat what is available.

Taste also affects animal preference of different plants. Some plants have no adverse taste, while others have an offensive taste which deters and limits consumption. The chemicals that produce bad tastes often interfere with the digestion and assimilation of nutrients and can make an animal sick if eaten in large amount. Table 4 is a listing of relative preference categories for the common species of Hill Country browse.

 

Brush vs Browse

Brush has a negative connotation, and most landowners would like to reduce if not eliminate certain brush species. Yet browse is considered a valuable asset and many landowners would like to have more of it. The paradox is that some of the most disliked brush species are also some of the most important browse plants.

Cedar, mesquite and persimmon are three of the most disliked brush species in the region and while not preferred, they are among the most important browse plants due to their abundance. These three brush species are among the top 10 browse plants (see Table 5), often making up one-third of the annual deer diet. Another side benefit of mesquite in addition to its use as browse is the growth of mistletoe, one of the best yearlong deer food plants found anywhere.

 

Browse Management

Browse management is an important habitat consideration for many Hill Country landowners. The most critical management aspect is balancing the number of browsing animals to the browse supply. Some parts of the Hill Country are so overpopulated with deer and exotics that the browse resource’s future is in jeopardy. In these areas, browse lines are evident on trees, and most shrubs are severely hedged, giving them the appearance of a bonsai plant.

This kind of over-browsing harms the plants’ vigor and productivity and virtually eliminates successful reproduction. Over time, the more desirable species are eliminated and the less desirable species increase. Under these conditions, browsing animals suffer malnutrition and poor performance. The remedy is not to feed deer to compensate for poor nutrition, but to balance the number of animals so that the habitat will improve.

Wildlife biologist Al Brothers, author of the book Producing Quality Whitetails, said, “The most cost-effective way to increase the deer food supply is to decrease the number of animals on the range.” This is especially hard to do in the Hill Country and requires a great deal of determination. It may also require the cooperative management of several adjacent ranches or the construction of a high fence.

For ranches where animal numbers are more or less in balance with the food supply, browse can be renovated by fire or mechanical means. Prescribed fire will top kill some shrubs and force them to re-sprout from the base. This enhances browse production and availability, and the new growth will be higher in nutritional quality. Roller chopping, dragging, hydro-axing or similar operations will do the same thing but are much more expensive.

A staggered program of browse renovation where 10 – 20 percent of the ranch is treated every other year is a good way to boost browse production and quality. Available browse production can often be doubled or tripled with an ongoing program of burning and/or mechanical renovation.

Selective brush management is also a good way to thin out the less desirable browse species such as cedar and allow the better species to increase. The goal should not be to eliminate cedar but to shift the dominance to other higher value browse. When cedar or other brush is mechanically removed, it is extremely beneficial to leave dead slash scattered on the ground rather than raking it into piles and burning it. The slash provides thousands of protected niches where desirable plants have a chance to get started.

Browse is an economically and ecologically important resource. Revenue generated by deer hunting is what keeps many Hill Country ranches viable, and those deer live mostly on browse. When landowners do a good job of managing browse, they also simultaneously protect biodiversity and maintain habitat for hundreds of other species.

 

Table 1  Browse Consumption Percentage of Wildlife and Livestock in the Hill Country

 

                                         Seasonal Range of           Average Yearly

Animal                            Browse Consumption     Browse Consumption

Whitetail                              32 - 100%                         72%

Goat                                     26 - 95%                           71%

Sika                                       34 - 70%                           54%

Fallow                                   8 - 75%                             33%

Axis                                       2 - 50%                             28%

Blackbuck                             2 - 60%                             27%

Sheep                                   8 - 51%                             23%

Aoudad                                 2 - 50%                             20%

Cow                                      0 - 73%                             15%

 

 

 

 

Table 2  Spring and Summer Browse Seasonal Variation in Nutritional Value

 

Plant                         Crude Protein                 Energy Value                 Month

Algerita                                16%                                  Very high                        March

Algerita                                8%                                    Very low                         May

Bumelia                                25%                                  Medium                         March

Bumelia                                14%                                  Low                                 July

Elbow bush                           21%                                  High                                March

Elbow bush                           7%                                    High                                October

Flameleaf sumac                  23%                                  High                                April

Flameleaf sumac                  11%                                  Low                                 July

Greenbriar                           28%                                  Very high                        April

Hackberry                            25%                                  Very high                        April

Hackberry                            8%                                    Low                                 July

Kidneywood                          24%                                  Medium                         April

Kidneywood                          17%                                  Medium                         October

Live oak                                12%                                  Medium                         May

Live oak                                10%                                  Very low                         September

Mesquite                              32%                                  High                                April

Mesquite                              16%                                  Very low                         June

Old man's beard                  22%                                  Medium                         April

Old man's beard                  15%                                  Medium                         July

Persimmon                           25%                                  High                                April

Persimmon                           10%                                  Low                                 July

Pricklyash                             18%                                  Very high                        May

Pricklyash                             15%                                  Very high                        October

Pricklypear                           7%                                    Very high                        July

Roemer acacia                     20%                                  Very high                        April

Roemer acacia                     13%                                  Medium                         September

Shin oak                                15%                                  High                                April

Shin oak                                11%                                  Low                                 October

Skunkbush sumac                14%                                  Very high                        March

Skunkbush sumac                11%                                  Very high                        May

 

 

 

 

Table 3  Evergreen Winter Browse Nutritional Value in Midwinter

 

Plant                               Crude Protein                 Energy Value

Cedar                                   7%                                    Medium

Ephedra                                12%                                  Very low

Evergreen sumac                 7%                                    Low

Greenbriar                           10%                                  Low

Live oak                                9%                                    Very low

Mistletoe                              17%                                  Medium

Pricklypear                           6%                                    High

Silktassell                             6%                                    Low

Tasajillo                                8%                                    High

 

 

 

Table 4  Relative Preference of Common Hill Country Browse Plants

 

Class 1                                  Class II                             Class III                           Class IV

Highly Preferred                 Preferred                        Non-Preferred              Least Preferred

Black willow                         Black cherry                     Button bush                    Algerita

Carolina buckthorn              Blackjack oak                   Evergreen sumac           Catclaw mimosa

Elms                                      Bumelia                           Feather dalea                 Cedar

Hawthorne                           Carolina snailseed           Flameleaf sumac            Cenizo

Kidneywood                          Dewberry                         Hogplum                        Condalia

Littleleaf leadtree                Elbowbush                       Lacy oak                         Fragrant mimosa

Madrone                              Ephedra                           Littleleaf sumac             Lotebush

Maple                                   Grapevine                        Live oak                          Mesquite

Mistletoe                              Greenbriar                       Peachbrush                    Mexican buckeye

Mountain mahogany           Hackberry                        Pecan                             Mountain laurel

Possumhaw                          Huisache                          Poison ivy                       Persimmon

Rusty blackhaw                    Old mans's beard            Post oak                         Pricklyash

Shrubby boneset                  Redbud                            Shin oaks                        Pricklypear

Snowbells                             Roemer acacia                Silktassel                        Tasajillo

Spanish oak                          Roughleaf dogwood         Skunkbush sumac          Wafer ash

Texas mulberry                    Virginia creeper              Sycamore                       Whitebrush

Texas sophora                      Western soapberry          Walnut                           Willow baccharis

White honeysuckle               Wild plum                                                              

 

 

 

Table 5  Top Ten Browse Plants of the Hill Country

Oaks

Cedar

Persimmon

Mistletoe

Mesquite

Sumacs

Acacias

Bumelia

Elbowbush

Hackberry



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