DALE ROLLINS, Texas Agricultural Extension Service, San Angelo, TX 76901
Abstract: The arrangement of woody plants on the landscape impacts biological and aesthetic functions and should be considered when planning brush control treatments. Factors to consider when planning landscape modifications include the owner’s management objectives, topography, plant communities, target species of wildlife, treatment options and the spatial arrangement of properties relative to the neighbors’. To facilitate implementation, clearing treatments should be sketched out on an aerial photograph, then those patterns demarcated clearly on the ground. By applying a knowledge of animal behavior, the habitat can be sculpted to enhance habitability of the site, plus enhancing visibility for hunting or viewing.
Webster’s 3rd International dictionary (Gove 1966) defines a landscape architect as “one whose profession is to arrange and modify the effects of natural scenery over tracts of land so as to produce the best aesthetic effect with regard to the use to which the tract is to be put.” Such a definition is not restricted to the golf course or the front yard of a suburban home. The same principles practiced by a landscape architect, e.g., natural beauty, aesthetics, are just as important when contemplating brush control. The main emphasis behind the Brush Sculptors program is the planned, selective removal of brush consistent with multiple use management. Landscape architecture is one component of such management.
In 1982 I was involved in a brush clearing study in Kerr County, Texas (Rollins et al. 1988) to determine how much brush could be removed from a site before affecting deer populations. We used double-chaining and burning to create a series of 20-acre clearings until 30, 50, 70 and 80% of a particular area had been cleared. The project was proceeding very well in July 1982; the clearings were producing 2 to 4 times more forage than the adjacent brushlands, and the deer were using clearings heavily. One day the local SCS District Conservationist brought out a neighboring (absentee) landowner to tour the study sites. As we entered one of the pastures that had been cleared at 50% intensity, we stepped out of the pickup truck to gaze upon contrasts between cedars and cleared areas. The visitor, a realtor from Houston, looked at the situation and remarked “my God, you’ve raped the land.” I was crushed! But his remark left an indelible mark in my mind.
Whether one is clearing brush on land he hopes to possess from now on, or on land that may be sold next month, he should carefully consider the short- and long-term impacts on the parcel’s appearance, productivity, and natural beauty. The planned, selective removal of brush can be one of the best things that ever happened to wildlife habitat; the unplanned, broadcast control of brush is perhaps the worst. In this paper, I will discuss the factors to consider when sculpting brush from the perspective of preserving the biological diversity on the site while maintaining or enhancing its natural beauty.
Applied landscaping can be practiced at different levels, including the:
(a) landscape level;
(b) individual clearing level;
(c) plant community level;
(d) plant species level; and
(e) individual plant level.
The animal’s perspective must also be addressed. Deer presumably need more and denser escape cover in an area that receives heavier hunting pressure (Swenson 1982). Clearing shapes and sizes are more critical for species with low mobility (e.g., bobwhites) than for more mobile species (wild turkeys).
Examples of each level will be presented. However, be aware that applied landscaping is a mixture of art and science; i.e., view these guidelines are starting points. The end product (i.e., resulting landscape) is limited only by the creativity of the sculptor, and perhaps by his pocketbook.
To fully grasp the view of your ranch at the landscape level, one must either get up on a hilltop, up in an airplane (or helicopter), or have an aerial photograph in hand. One must have an appreciation for the spatial arrangement of various brush densities, water courses, lay of the land (i.e., topography) and the neighbors’ adjoining lands. An aerial photograph obtained from your local Natural Resources Conservation Service is an invaluable planning aid.
At the landscape level, one should be cognizant of special sites that should be either (a) enhanced or (b) preserved. I often refer to this level of planning as one addressing “honeyhole brush management.” Some areas of the property are inherently more attractive to deer (Odocoileus spp.) or bobwhites (Colinus virginianus) than other areas. Such honeyholes may be charac-terized by particular species of brush (e.g., sand plum [Prunus angustifolia]), brush stands of certain age/size, brush species diversity, topography, remoteness or other factors.
Honeyholes for a particular species require a thorough knowledge of the target wildlife species’ biology and habits on the particular property. Which way do the deer “flow” when disturbed? Are there certain key travel lanes that dictate the use of some areas of the ranch (e.g., feeding areas)?
In order to manage at the honeyhole-level, I recommend that the manager close his eyes and visualize where he would go at noon to jump that trophy buck or flush a covey of quail. Once that location is visualized, study the picture; how dense is the brush? What species of brush are involved? Is it in a draw? A header of a canyon? When the image of the honeyhole is vivid, consider the task at hand: to clone (i.e., “cut and paste”) such honeyholes across the landscape.
How large is a honeyhole? For deer, the area might be as small as a basketball court or as large as 30 acres, depending on the site. For quail, it might be a key lotebush (Zizyphus obtusifolia) or a draw of several hundred yards containing scattered thickets of sandplum and skunkbush (Rhus trilobata). Try to identify what feature(s) are integral components of honeyholes for the particular species of wildlife for which you are managing, then tailor your sculpting plans to clone such features.>
Another concern is critical habitats. In the Endangered Species Act, the phrase “critical habitat” has legal meaning; herein I use the phrase to indicate key habitats for a particular species. For example, habitat for wild turkeys (Meleagris gallopavo) often revolves around suitable roost sites. Usually such sites are well known by the land manager and are not the target of most brush control efforts. The bottom line is that the integrity of these sites should be preserved. Selective clearing and thinning of shorter brush is permissable. Winter roosts are typically more “sacred” than roosts during the summer, so plan your control efforts during months when the winter roosts are less vulnerable to the disturbance associated with brush clearing.
Topography is an important factor at the landscape level. Depending on the landowner’s objectives, the vista desired may look like an open savanna or a mosaic of open areas with denser brush interspersed therein. Wildlife like deer often use topography as a sort of “cover.” A deer that can move over the ridge is screened just as effectively as one that moves into a dense cedar (Juniperus spp.) brake.
Topography, soils, and site potential for forage production are related. Usually, dense brush occurs more commonly along headers and along rocky draws. However, these sites have limited forage production potential (excluding browse) because of shallow soils. Thus, sparing such areas makes sense economically. Deeper soils are normally found in the flats and such areas have greater production potential. Clearing too much brush from bottomland areas may reduce their attractiveness to deer (Darr and Klebenow 1975). Brush should normally not be cleared within 25 yards (or so) of the stream course. Similarly, brush should be preserved along feeder draws that service streams and “saddles” between headers, as these areas provide important travel lanes (Hailey 1979).
Individual clearing level
Species of animals have various “security thresholds”, i.e., a sense of security that comes with proximity to escape cover. If clearings become too large, and the security threshold is exceeded, then the center portion of that clearing become “lost habitat” relative to that species of wildlife. As a rule, more smaller clearings are preferred over fewer, but larger, clearings. Maximum clearing width for deer is generally recommended to be 400 yards; 200 yard widths are preferred. Quail typically do not forage more than 50 yards from woody cover, so maximum clearing width shouldn’t exceed twice that (i.e., 100 yards).
Clearings can be landscaped in several ways. First, the edges shouldn’t be straight lines. Straight lines aren’t “natural” and result in stark visual contrasts between brush and cleared areas. Contoured edges, or “feathered” edges, are more aesthetically pleasing, as they look more natural. Long, straight clearings should be interrupted by doglegs of brush or “ziz-zag” clearings to where a deer cannot see over 200 yards. Another option is to leave mottes of trees intact on larger clearings. Often, liveoak (Quercus virginiana) mottes are spared during mechanical clearing operations. For quail, leave a “stringer” of brush extending into larger clearings, but avoid isolated coverts, as these may become “ecological traps” that make the isolated quail more vulnerable to avian predators.
In mechanical clearing operations, there is always the slash that is either left in place, stacked with a rake, or windrowed (as in chaining). Typically such brushpiles are burned. Some managers like to leave brush piles on clearings, but my preference is to burn them. Larger brushpiles typically harbor more skunks and snakes than they serve as cover for quail. I’d much rather leave selected mottes of quail cover than try to use brush piles as a substitute for planning. One very good use that I’ve found brushpiles for is calling for coyotes (Canis latrans). Coyotes recognize brushpiles as good mousing habitat, and using a brushpile for a calling stand can be very productive. If brushpiles in areas with shinoak (Quercus spp.) are to be burned, try to stack the piles on top of shinoak areas. Such brush piles burn very hot and may sterilize the soil, but I’ve never seen them get so hot to kill shinoak. And, the shinoak resprouts are very palatable to deer and exotic ungulates (e.g., aoudads [Ammotragus lervia]) (Rollins 1983).
Plant community level
Most species of wildlife express an affinity for certain vegetation types (plant communities). For species like deer this may include a wide range of situations, whereas black-capped vireos (Vireo atricapillus) are more of a niche specialist. As such, my two main axioms for range manages is (a) know your plants and (b) know how to manipulate them. Whether your interests lie with black baldy steers or white-tailed deer, cows or quail, these premises apply. Know which species of plants are important for your target wildlife species, then know what management tools (i.e., the “axe, plow, cow, and fire”) foster those plants. Remember to think beyond just food value before such judgements are made (i.e., “Cadenhead’s Corollary”).
Wildlife density and diversity typically correlate with plant diversity (woody and herbaceous). Even within a species (e.g., deer), individual animals tend to select those areas within the habitat that are more diverse (Pollock et al. 1994). The Brush Sculptor’s goal should be to at least maintain species diversity, and hopefully increase it. This requires certain assumptions, namely that the managers (a) can recognize identify the various woody species that are found on the site, and (b) that he understands the relative values that the species provides for various species of wildlife. Field guides (e.g., Everitt and Drawe 1992), other publications (e.g., Gee et al. 1989) color posters (e.g., Rollins and Cadenhead 1992), and electronic sources (e.g., TEXNAT [https://texnat.tamu.edu] are available to facilitate identification. Other sources, including several papers in these proceedings, provide information on forage value for deer.
A central thesis for sculpting brush is the ability to remove brush selectively. Generally mechanical means afford the greatest selectivity during brush clearing operations. Tree-dozing or chaining afford excellent selectivity, if the operator(s) take advantage of that ability.
Herbicides can also be used to provide selective control, but generally not to the degree of fine-tuning available with mechanical means. However, with the inception of individual plant treatments (e.g., Brush Busters [McGinty and Ueckert 1995]), the applicator can be highly selective. For broadcast applications, the use of pelleted herbicides (e.g., tebuthiuron) in backpack “blowers” offer more precise applications. To a lesser degree, the selection of broadcast foliar sprays may provide some measure of what brush species are killed (Hanselka et al. 1994).
At the community level, desirable trees should be spared during clearing efforts. For the more desirable species, I recommend that all individuals of that species be spared; for others they should be spared, but not necessarily all of them. In the Rolling Plains, species such as netleaf hackberry (Celtis reticulata), chittam (Bumelia lanuginoides) and skunkbush should receive complete protection. Other species such as lotebush and sandplum should be spared in moderation, and in those areas where they are components of honeyholes. In the Trans-Pecos region, acacias (Acacia spp.), allthorn (Koerberlinia spinosa) and javelina brush (Condalia ericoides) are examples of plants that should be spared.
Mesquite (Prosopis glandulosa) is perhaps the most despised plant in Texas, yet mesquite is an important habitat component for quail, deer and several other nongame birds (Jackson 1969, Rollins 1981). In the Edwards Plateau, Ashe juniper (Juniperus asheii) is often the target of intensive control, but junipers can be an important source of winter forage and escape cover for wildlife (Rollins and Armstrong 1997). Similarly, pricklypear (Opuntia spp.) is often dismissed as without value, yet recent studies suggest it may be an important habitat for nesting quail (Carter 1995, Slater 1996).
Within most species of woody plants, some individual plants are more preferred than others, be it for forage (Rollins 1983) or cover. When these “preferred” trees can be identified, they should be spared during control efforts. In Ashe juniper, one can look under and near the dripline of the tree (usually older, female trees) for fecal pellet groups in February and March to indicate the use by white-tailed deer. Some mesquite trees assume a growth form that makes them desirable loafing coverts for quail, while others are rarely used. Knowledge of a particular site attained through hunting over a period of years helps to identify which microsites are important habitats, and usually which individual trees are most likely to be frequented by quail.
When such trees are identified, realize that their importance may be associated with the complex of species or growth types, so sculpt such areas deliberately. The carpenter’s advice of “measure twice and saw once” is good advice for sculpting brush. It’s easier to have to come back and take out more brush at a later date than it is to rebuild a honeyhole.
Sculpting for hunting ease
Brush clearing is a bit like a prescribed fire; one can accomplish multiple objectives simultaneously. To that end, multiple factors should be considered when planning brush treatments. In recent years, more managers have used their brush clearing patterns to facilitate the observation of game for hunting or photography. The American Indians used fire to manipulate the movements of bison (Bison bison), either directly or indirectly (i.e., attracting them to better grazing) for hundreds of years. I think this is one of the best uses for sculpting brush, and hope that some day the landscaping of the area replaces the prominence of the corn feeder in deer hunting circles.
Clearings facilitate the observation of game by (a) increasing visibility across an area, and (b) attracting the animals because of improved foraging conditions on the clearing itself. In order to optimize these two factors, the clearings should be constructed to maximize the sense of security that the animals have while in a clearing. Usually this means attention to clearing dimensions as discussed earlier. Senderos (linear clearings associated with pasture roads, fences or pipelines) are preferred hunting areas in brushy south Texas. Senderos can also be installed strictly for hunting purposes. One arrangement is to cut two senderos in an “X” fashion, leaving the brush at the intersection of the brush for placement of a tripod hunting blind. The length of the “legs” of the X should not exceed 250 yards, as this is the maximum distance that most hunters could be expected to shoot a deer accurately.
Less sculpting for hunting purposes has been done to facilitate quail hunting, but this trend is increasing. Typically, the brush strips that are spared are laid out perpendicular to the prevailing winds to facilitate a bird dog’s abilities to detect the quail’s scent when traveling down a road parallel to the brush strip.
The only ingredients necessary to successfully sculpt brush are (a) having a goal in mind, (b) committing one’s self to making it successful, (c) an aerial photograph, and (d) some flagging tape. A computer with a “paint” program is a handy item for visualizing various treatment arrangements, but a red pencil or grease pencil will suffice to mark the location of clearings on the photograph.
Take the aerial photograph and “digitize” it (i.e., have it scanned as a “bitmap” (.bmp) or “paint” file (.pcx). Use a software program like PowerPoint or other imaging capabilities to retrieve the file and learn how to use the software to “paint” the image with the clearings you desire. Using this setup will allow you to visualize variously sized clearings, honeyholes, and the spatial arrangements among clearings and the topography of the site (Fig. 1).
Once the aerial photograph is marked for clearing, the task is to communicate successfully your clearing desires to the contractor (e.g., dozer operator). Don’t assume that your verbal instructions will be taken verbatim! I’ve seen several wrecks caused by a lack of communication between the planner and the contractor. Most bulldozer operators will not appreciate the complexity of your designs, so be prepared to spend some time with them in the field to make sure they have a good understanding of your clearing plans. Clearing borders should be marked with flagging tape, and any special instructions should be clearly marked. Trees that should be spared within a clearing should also be conspicuously marked with flagging tape.
The inception of affordable Global Positioning Systems (GPS) will become more common for designing brush sculpting plans. Such equipment is currently being used by many aerial applicators.
Considerable research on the impacts of brush management on wildlife has been conducted in Texas since the late 1970s, as evidenced by these proceedings. Much of this research was aimed at quantifying the “action-reactions” associated with changing the landscape from a brushland to a savanna to a grassland. As wildlife become more important in land use planning, more efforts will be made to clearly define and optimize the use of brush management (i.e., sculpting) as a habitat management tool.
Some questions that need to be addressed (in no particular order) include:
(1) refine the optimal clearing intensity for key wildlife species in various habitats (Rollins et al. 1988) in both high-fenced and regularly-fenced sites;
(2) evaluate the utility of GPS systems for facilitating logistics of sculpting brush;
(3) evaluate recruitment (i.e., fawn survival, nest success) in areas sculpted to various intensities;
(4) determine if sculpting brush produces a numerical (i.e., population) response in the target wildlife species, and if so, document the processes involved (e.g., enhanced nutrition).
(5) monitor the long-term species changes in plant communities as affected by various clearing strategies.
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Darr, G. W., and D. A. Klebenow. 1975. Deer, brush control, and livestock on the Texas rolling plains. J. Range Manage. 28:115-119.
Fulbright, T. E., and S. L. Beasom. 1987. Long-term effects of mechanical treatments on white-tailed deer browse. Wildl. Soc. Bull. 15:560-564.
Gee, K. L., M. D. Porter, S. Demarais, F. C. Bryant, and G. Van Vreede. 1991. White-tailed deer: Their foods and management in the Cross Timbers. Samuel Roberts Noble Foundation, Ardmore, OK.
Hailey, T. L. 1979. Basics of brush management for white-tailed deer production. Texas Parks Wildl. Dept. Booklet 7000-35.
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Rollins, D. 1991. Managing brushlands for wildlife. Pages 31-39 in T. G. Welch (ed) Proc. Brush Management Symposium. Texas Agric. Extension Serv., College Station.
Rollins, D. 1983. Wildlife response to different intensities of brush removal on the Edwards Plateau of Texas. Diss., Texas Tech Univ., Lubbock. 70pp.
Rollins, D., F. C. Bryant, D. D. Waid, and L. C. Bradley. 1988. Deer response to brush management in central Texas. Wildl. Soc. Bull. 16:277-284.
Rollins, D., and W. E. Armstrong. 1997. Cedar through the eyes of wildlife. In C. A. Taylor, Jr. (ed) Proc. Juniper Symp., Texas A&M Univ. Research and Extension Center Publ. 97-1. San Angelo.
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Updated: Mar. 18, 1997