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Wildlife, Animals, and Plants |
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VALUE AND USE
WOOD PRODUCTS VALUE:Wood of alligator juniper currently has little commercial value. Springfield [120] suggests the wood may have potential for producing pulp, fiber, chip products, and particleboard. Veneer has been made out of alligator juniper on an experimental basis, but large trees are too few and scattered in most locations to make this venture economically feasible [6,103]. Volume estimates from upper woodland zones of Arizona range from 100 to 250 feet3/acre and average 150 feet3/acre. At lower elevations volume averages only 109 feet3/acre [10]. Alligator juniper can be made into particleboard and is occasionally milled as lumber. The wood is also used to make furniture. It is most commonly used to make various novelty products such as bookends, lamp bases, or small chests. Alligator juniper wood is fragrant with an attractive color and grain [10]. Alligator juniper makes excellent firewood of relatively high heat value [103]. The wood is light, easy to split, and burns with a pleasant aroma [115]. It provides an estimated 243,000 BTUs/foot3. Weight (lbs) per standard cord has been measured as follows [10]:
density - 40 lbs/ft3 modulus of elasticity - 272,000 lbs/in3 strength: modulus of rupture - 3.430 lbs/in3
IMPORTANCE TO LIVESTOCK AND WILDLIFE:Alligator juniper is an important component of the southern portion of pinyon-juniper woodlands. This association provides good quality habitat for numerous species including mule deer, bighorn sheep, pronghorn, wild horse, coyote, bobcat, badger, porcupine, rabbits, mice, voles, woodrats, squirrels, and many species of birds [41]. Alligator juniper provides shade and shelter for wildlife and livestock. Pinyon-juniper woodlands provide valuable winter and, in some instances, year-round range for elk, deer, and livestock in parts of Arizona and New Mexico [112]. Both mule deer and white-tailed deer use alligator juniper stands in parts of southeastern Arizona [5]. At least 73 species of birds are known to breed in pinyon-juniper, and 32 species overwinter in these woodlands [56]. The berry-like cones of alligator juniper remain on the tree for a considerable length of time and, when abundant, provide a rich and readily available food source for many birds and mammals [6,41]. Cone-berries of junipers are often available at a time of year when other food sources are scarce [56]. Some researchers report that bird densities in pinyon-juniper woodlands may be up to 70% greater during bumper cone years than in average years [9]. Both birds and mammals are capable of consuming large quantities of juniper cone-berries and are extremely important dispersal agents [6]. Cone-berries provide food for coyotes during the summer, fall, and winter; they assume particular importance during the fall [105]. In some areas, both deer and elk eat juniper cone-berries during the winter months [119]. Alligator juniper is also an important food source for the collared peccary in parts of New Mexico [19]. Alligator juniper cone-berries are believed to be an important component in winter wild turkey diets in north-central Arizona [131]. "Cone-berries may be particularly important to wild turkeys during drought years [50]. In New Mexico, an endangered subspecies of wild turkey, the Gold's turkey, feeds on alligator juniper [102]. The prevalence of juniper cone-berries may determine the densities of overwintering birds such as the Townsend's solitaire, western and mountain bluebirds, and the American robin [50]. Some avian species consume both the pulpy flesh and seeds of juniper cone-berries (Cassin's finch, evening grosbeak); others, which are more important dispersal agents, digest only the pulp and disperse the seed (bluebirds, American robin, and Townsend's solitaire) [56]. The foliage of alligator juniper is apparently somewhat more palatable than the foliage of most other junipers [32] and, consequently, is more often utilized as browse. Research indicates that the mean volatile oil content of alligator juniper is less than that of either Rocky Mountain or Utah juniper. Foliage is also believed to have less of an inhibitory effect on bacterial rumen of deer [116]. Alligator juniper is reported to be an important year-round mule deer food in parts of New Mexico [88]; in southeastern New Mexico, it is considered a major food item from January through March [113]. In parts of south-central New Mexico, it is a common although not preferred item in mule deer diets [87]. In the Dos Cabezos Mountains of southeastern Arizona, alligator juniper is reported to be one of the seven most important foods of both mule deer and white-tailed deer. Although important to both species, it was eaten nearly twice as often by mule deer [5]. The foliage of alligator juniper frequently represents a major item in elk diets in Arizona ponderosa pine stands [28]. It has little forage value for most livestock but is sometimes eaten by domestic goats [32,75].
PALATABILITY:The foliage of alligator juniper relatively unpalatable to livestock and most wild ungulates. Palatability of alligator juniper for mule deer has been reported as follows [76,100]: winter - high to low spring - moderate to low summer - moderate to low fall - high
NUTRITIONAL VALUE:Little specific information exists on the food value of alligator juniper. The cone-berries apparently provide at least moderate energy for a number of bird species [9]. Researchers have estimated the average energy value of a juniper cone-berry at 315.31 calories [114].
COVER VALUE:Alligator juniper provides shade and shelter for many wildlife species and for domestic livestock [29]. Woodrats are known to use alligator juniper as support structures for nests [126]. A New Mexico study found that the percentage of shelters that white-throated woodrats constructed from alligator juniper was as follows [126]: live trees 4.3 dead trees 2.2 The broad-tailed hummingbird, acorn woodpecker, ash-throated flycatcher, Mexican jay, black-crested titmouse, bushtit, blue-gray gnatcatcher, and rufous-crowned sparrow breed in pinyon-juniper habitats dominated by alligator juniper in the Chisos Mountains of Texas [132]. Alligator junipers provide nest sites for many bird species, and older trees may contain hollow cavities at the bases that are used by cavity nesters [93]. Alligator junipers provide hiding and thermal cover and migration corridors for a variety of animals. Young trees provide cover for elk, deer, and small mammals. This cover may be particularly important when deep snows make other food sources unavailable [98]. Miller and Wigand [93] report that mule deer often move from shrub communities to juniper woodlands during winter stress periods.
VALUE FOR REHABILITATION OF DISTURBED SITES:Alligator juniper aids in preventing erosion on harsh sites [30]. It can be successfully propagated by seed [7].
OTHER USES AND VALUES:Wood of alligator juniper was formerly made into charcoal in parts of the Southwest [6]. During historic times the wood of many species of juniper was used as fenceposts, poles, mine timbers, fuel for the mining industry, and railroad ties [8,10,41]. Springfield [120] notes that juniper wood may have potential for use in making charcoal and for producing certain chemicals. Wood extractives of alligator juniper may be of value although the precise characteristics of the extractives of this species are poorly known. Extractives from morphologically similar species are used in making pharmaceuticals, perfumes, polishes, and insecticides [10]. Juniper wood is associated with traditional values in a number of Native American cultures. The wood has traditionally been used in construction of pueblos and hogans, and for making corrals and fences [94]. The cone-berries of alligator juniper were used in traditional foods, medicines, teas, and in ceremonial incense [30,94,95]. The Zuni used alligator juniper cone-berries to flavor foods such as cornbread and blood sausage. They used the shreddy bark to make torches [95].
MANAGEMENT CONSIDERATIONS:Pinyon-juniper woodlands have been increasing in extent since settlement times. In many parts of the Southwest, alligator juniper and other species have encroached into adjacent grasslands [60,99,134]. A decrease in fire frequency has often been cited as the probable cause of this increase [133]. However, overgrazing offers another possible explanation. Past management efforts have largely focused on halting the juniper "invasion" through mechanical or chemical means. Little regard was given to possible wildlife use of these areas or to potential wood products value of juniper species. In a number of instances, juniper removal alone does little to increase long-term forage potential. Miller and Wigand [93] note that although juniper is largely accepted as providing beneficial wildlife habitat, there is significant disagreement as to how much juniper is optimal, the acceptable size of treated areas, the effect of thinning as opposed to total juniper removal, and whether particular sites should or should not be treated. Several types of mechanical treatments have been used with varying success in converting pinyon-juniper woodlands to grasslands. Cabling, chaining, bulldozing, and other mechanical means of removal are most effective in eliminating mature, even-aged, nonsprouting junipers in stands of approximately 250 trees or less per acre. Elimination of alligator juniper is often difficult however, because of its proclivity to sprout following disturbance. Even repeated defoliation may be ineffective [65]. Brush choppers, hand-cutting, and rottocutters also appear to be relatively ineffective for killing alligator juniper [120]. According to Jameson and Johnsen [62], the root crown must be removed for good results to be obtained through mechanical control. Severson [117] reported little difference between treated and untreated plots in New Mexico 13 to 18 years after mechanical removal. No significant differences were detected between untreated and thinned plots or between pushed/left and pushed/piled/burned plots, although significant (p <0.05) differences were observed between bulldozed and untreated/thinned treatments. Density (stems/ha) of alligator juniper on four treatments in 1983 was as follows [117]:
Herbicide application is frequently combined with mechanical removal to increase alligator juniper mortality [63]. In some instances, basal sprouts from mechanically treated trees can be killed by herbicides. Junipers can reportedly be killed by such chemicals as arsenite, ammonium sulfate, esters of 2,4-D and 2,4,5-T, and polychlorobenzoic acid [120]. Variable results have been obtained with picloram or tebuthiuron [65]. Specific research has been conducted on application of various herbicides on alligator juniper [27,62,65,92]. Site characteristics can influence the effectiveness of herbicides on alligator juniper. Herbicides more often kill junipers on ridges and slopes than on bottomlands [65]. Frequently, trees on deeper soils remain undamaged after herbicide application [65]. Slope, rooting depth, and density of the top growth can all greatly influence the effectiveness of herbicide treatments [63]. Many pinyon-juniper ranges in which alligator juniper is well represented are now in relatively poor condition. Humphrey [57] reports that blue grama, sideoats grama, Stansbury cliffrose (Purshia mexicana var. stansburiana), silktassel (Garrya spp.), and Indian ricegrass (Achnatherum hymenoides) occur commonly on alligator juniper ranges of Arizona in good condition, with the cover of such species as bottlebrush squirreltail, goldeneye (Viguiera spp.), birdbeak (Cordylanthus parviflorus), and broom snakeweed (Gutierrezia sarothrae) increasing with overgrazing. The following species are indicative of range condition on some Arizona alligator juniper sites [57,58]: excellent: black grama (Bouteloua eriopoda), Indian ricegrass, blue grama, winterfat (Krascheninnikovia lanata), Stansbury cliffrose, and fourwing saltbush (Atriplex canescens) good: Indian ricegrass, black grama, blue grama, needlegrass (Stipa spp.), and spike muhly (Muhlenbergia wrightii) fair: blue grama poor: broom snakeweed, ringgrass (Muhlenbergia torreyi) Somewhat variable results have been obtained following alligator juniper removal aimed at returning woodlands to grasslands to increase forage production. In some Arizona alligator juniper savannas, early grass production is as much as 4 to 5 times greater under the crowns of junipers than in the interspaces. Forage species such as mutton bluegrass (Poa fendleriana), bottlebrush squirreltail, prairie junegrass (Koeleria macrantha), and western wheatgrass (Pascopyrum smithii) particularly benefit from the shade of large alligator junipers. Researchers report that nearly all livestock utilization occurs under the crown of large alligator junipers in these savannas. In many cases the removal of large alligator junipers results in the elimination of readily utilizable cool-season forage and produces only a small increase in warm season forage. Since these areas are most often used as spring-fall ranges, results are usually not beneficial to livestock [29]. Clary [25] reports somewhat better results following treatment of north-central Arizona juniper sites. Here the removal of 13% of the alligator juniper produced a 38% increase in total herbage production and a 45% increase in forage plant production. Untreated areas produced approximately 635 pounds of herbage per acre and 292 pounds of forage per acre, whereas the treated sites produced 877 pounds of herbage per acre and 423 pounds of forage per acre. Much of the increased production was in bottlebrush squirreltail or western ragweed (Ambrosia psilostachya). Generally, production and grazing opportunities reach a peak within a year or two after treatment. Overall, herbage production is variable in alligator juniper communities. Juniper is characterized by a slow growth rate and rotations on "typical" pinyon-juniper sites are thought to average around 200 years. Rotations of 300 years are more usual on poor sites [91]. A modified simulated shelterwood cut can be used where advance regeneration is adequate, but clear-cuts and seed-tree cuts generally give unsatisfactory regeneration. Two and three cut shelterwood cuts are being evaluated [48]. The coppice method can be considered where maintaining alligator juniper is a goal [38].
Related categories for SPECIES: Juniperus deppeana | Alligator Juniper |
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