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|Photo courtesy of James Manhart, Texas A&M University|
|UPDATE OF THIS SPECIES REVIEW:|
|In March 2007, an extensive search was done to locate information on drooping juniper; see the list of source literature for the sources consulted. Little information was found, but that information has been added to the original review, and the references list has been updated. In substance, the review has changed very little from that originally published in 1993.|
|A. Scott Hauser, April 24, 2007|
Juniperus flaccida var. flaccida Schlecht. [14,15]
Juniperus flaccida var. martinezii (Pérez de la Rosa) Silba
Juniperus flaccida var. poblana Martinez 
Photo courtesy of James Manhart, Texas A&M University
GENERAL BOTANICAL CHARACTERISTICS:
This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. An identification key is available .
Drooping juniper is a native small tree or large shrub that is slow growing and long-lived . Height at maturity usually ranges from 25 to 30 feet (7.6-9.1 m) [37,44]. The national champion tree occurs in Juniper Canyon and is 55 feet (17 m) tall with a crown spread of 35 feet (11 m) and a circumference of 8.5 feet (2.5 m) . Juniperus flaccida var. flaccida reaches a maximum height of 39 feet (12 m) . The most conspicuous character of drooping juniper is its pendant branchlets [33,44]. Young drooping juniper trees usually have a narrow rounded crown. The bark is deeply furrowed and shreds into long strips . The globose, berrylike cone is from 0.25 to 0.5 inch (0.63-1.3 cm) in diameter . Each drooping juniper cone contains from 4 to 12 seeds (usually 6-8) that are 0.12 to 0.25 inch long [33,38,44]. The cones of J. f. var. flaccida contain from 4 to 13 (usually 6-10) seeds . Drooping juniper cones collected by Adams  in the Chisos Mountains averaged 8.35 seeds/cone.
Toxicity: The leaves of J. f. var. flaccida and J. f. var. poblana contain volatile oils [1,3]. The composition of volatile leaf oils in both varieties is available .RAUNKIAER  LIFE FORM:
Pollination: Drooping juniper is pollinated by the wind.
Breeding system: Drooping juniper is dioecious [42,43,44].
Seed dispersal: Drooping juniper seeds are dispersed by birds and animals .
At the time of this review (2007) there is no information relating to drooping juniper seed banking, production, or germination; seedling establishment or growth; or vegetative regeneration. Research on drooping juniper reproduction is sorely needed.SITE CHARACTERISTICS:
Climate: Where drooping juniper grows in the Chisos Mountains, precipitation ranges from 8.7 to 27 inches (220-680 mm), with most falling from May to October [26,45]. It rarely freezes, and summer temperatures routinely exceed 100 °F (40 °C) .
Elevation: In the Chisos Mountains, drooping juniper generally is found above 5,000 feet (2,000 m) . In Mexico, it occurs from 4,000 to 8,000 feet (1,000-2,000 m) [3,44]. The elevational range of J. f. var. flaccida in Texas and Mexico is 3,000 to 9,500 feet (900-2,900 m) .SUCCESSIONAL STATUS:
Fire regimes: Fire is a common occurrence where drooping juniper occurs in the Chisos Mountains. Dick-Peddie and Alberico  reported that lightning fires are probably highly localized, and are often confined to single trees. Downed woody fuels are usually scarce, and continuous fine fuels consist of herbs . Using fire scar data, Moir  assessed that fire frequency in the Chisos Mountains ranged from 0.9 to 2.0 fires/century. The research conducted by Moir suggests a mean fire interval for the Chisos Mountains of approximately 70 years [29,30]. Research conducted by Leopold and Krausman  in the Chisos Mountains showed a mean fire interval of 60 years.
The following table provides fire-return intervals for plant communities and ecosystems where drooping juniper is important. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||<35 to <100|
|pinyon-juniper||Pinus-Juniperus spp.||<35 |
|Mexican pinyon||Pinus cembroides||20-70 [30,40]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||<35 to <200 |
Palatability/nutritional value: No information is available on this topic.
Cover value: No information is available on this topic.VALUE FOR REHABILITATION OF DISTURBED SITES:
Wood Products: Drooping juniper wood is durable and is used locally for fenceposts [42,44].OTHER MANAGEMENT CONSIDERATIONS:
1. Adams, R. P. 1972. Chemosystematic and numerical studies of natural populations of Juniperus pinchotii Sudw. Taxon. 21(4): 407-427. 
2. Adams, Robert P. 1973. Reevaluation of the biological status of Juniperus deppeana var. sperryi Correll. Brittonia. 25(3): 284-289. 
3. Adams, Robert P.; Zanoni, Thomas A.; Hogge, Lawrence. 1984. The volatile leaf oils of Juniperus flaccida var. flaccida and var. poblana. Journal of Natural Products. 47(6): 1064-1065. 
4. American Forests. 2007. Drooping juniper: Juniperus flaccida. In: National register of big trees, [Online]. Available: http://www.americanforests.org/resources/bigtrees/ [2007, April 24]. 
5. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. 
6. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. 
7. Arno, Stephen F.; Scott, Joe H.; Hartwell, Michael G. 1995. Age-class structure of old growth ponderosa pine/Douglas-fir stands and its relationship to fire history. Res. Pap. INT-RP-481. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 25 p. 
8. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. 
9. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. 
10. Dick-Peddie, William A.; Alberico, Michael S. 1977. Fire ecology study of the Chisos Mountains, Big Bend National Park, Texas: Phase I. CDRI Contribution No. 35. Alpine, TX: The Chihuahuan Desert Research Institute. 47 p. 
11. Duncan, Wilbur H.; Duncan, Marion B. 1988. Trees of the southeastern United States. Athens, GA: The University of Georgia Press. 322 p. 
12. Elias, Thomas S. 1980. The complete trees of North America: field guide and natural history. New York: Times Mirror Magazines, Inc. 948 p. 
13. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
14. Farjon, Alijos. 1998. World checklist and bibliography of conifers. 2nd ed. Kew, England: The Royal Botanic Gardens. 309 p. 
15. Flora of North America Association. 2007. Flora of North America: The flora, [Online]. Flora of North America Association (Producer). Available: http://www.fna.org/FNA. 
16. Floyd, M. Lisa; Romme, William H.; Hanna, David D. 2000. Fire history and vegetation pattern in Mesa Verde National Park, Colorado, USA. Ecological Applications. 10(6): 1666-1680. 
17. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
18. Geils, B. W.; Wiens, D.; Hawksworth, F. G. 2002. Phoradendron in Mexico and the United States. In: Geils, Brian W.; Cibrian Tovar, Jose; Moody, Benjamin, tech. coords. Mistletoes of North American conifers. Gen. Tech. Rep. RMRS-GTR-98. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 19-28. 
19. Gottfried, Gerald J.; Swetnam, Thomas W.; Allen, Craig D.; Betancourt, Julio L.; Chung-MacCoubrey, Alice L. 1995. Pinyon-juniper woodlands. In: Finch, Deborah M.; Tainter, Joseph A., eds. Ecology, diversity, and sustainability of the Middle Rio Grande Basin. Gen. Tech. Rep. RM-GTR-268. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 95-132. 
20. Jones, Stanley D.; Wipff, Joseph K.; Montgomery, Paul M. 1997. Vascular plants of Texas. Austin, TX: University of Texas Press. 404 p. 
21. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. In: North Carolina Botanical Garden (Producer). In cooperation with: The Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service. 
22. Keeley, Jon E. 1981. Reproductive cycles and fire regimes. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; Lotan, J. E.; Reiners, W. A., tech. coords. Fire regimes and ecosystem properties: Proceedings of the conference; 1978 December 11-15; Honolulu, HI. Gen. Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 231-277. 
23. Knobloch, Irving W. 1942. Notes on a collection of mammals from the Sierra Madres of Chihuahua, Mexico. Journal of Mammology. 23(3): 297-298. 
24. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. 
25. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., tech. coords. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. 
26. Leopold, Bruce D.; Krausman, Paul R. 2002. Plant recovery and deer use in the Chisos Mountains, Texas, following wildfire. Proceedings, Annual Conference of Southeastern Association of Fish and Wildlife Agencies. 56: 352-364. 
27. Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb. 541. Washington, DC: U.S. Department of Agriculture, Forest Service. 375 p. 
28. Mitchell, Alan F. 1972. Conifers in the British Isles: A descriptive handbook. Forestry Commission Booklet No. 33. London: Her Majesty's Stationery Office. 322 p. 
29. Moir, William H. 1980. Forest and woodland vegetation monitoring, Chisos Mountains, Big Bend National Park, Texas: Baseline 1978. Contribution No. 83. [Fort Davis, TX]: Chihuahuan Desert Research Institute. 63 p. 
30. Moir, William H. 1982. A fire history of the High Chisos, Big Bend National Park, Texas. The Southwestern Naturalist. 27(1): 87-98. 
31. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; Gottfried, Gerald J.; Haase, Sally M.; Harrington, Michael G.; Narog, Marcia G.; Sackett, Stephen S.; Wilson, Ruth C. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. 
32. Plumb, Gregory A. 1992. Vegetation classification of Big Bend National Park, Texas. Texas Journal of Science. 44(4): 375-387. 
33. Powell, A. Michael. 1988. Trees and shrubs of Trans-Pecos Texas: Including Big Bend and Guadalupe Mountains National Parks. Big Bend National Park, TX: Big Bend Natural History Association. 536 p. 
34. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
35. Schoenhals, Louise C. 1988. A Spanish-English glossary of Mexican flora and fauna. Tucson, AZ: Summer Institute of Linguistics, Mexico. 637 p. 
36. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
37. Simpson, Benny J. 1988. A field guide to Texas trees. Austin, TX: Texas Monthly Press. 372 p. 
38. Standley, P. C. 1924. Trees and shrubs of Mexico. Contrib. U.S. Nat. Herb. Washington, DC: Smithsonian Press. 23: 849-1312. 
39. Stickney, Peter F. 1989. FEIS postfire regeneration workshop--April 12: Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. 10 p. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
40. Swetnam, Thomas W.; Baisan, Christopher H.; Brown, Peter M.; Caprio, Anthony C. 1989. Fire history of Rhyolite Canyon, Chiricahua National Monument. Tech. Rep. No. 32. Tucson, AZ: University of Arizona, School of Renewable Natural Resources; Cooperative National Park Resources Studies Unit. 47 p. 
41. U.S. Department of Agriculture, Natural Resources Conservation Service. 2007. PLANTS Database, [Online]. Available: https://plants.usda.gov /. 
42. Van Dersal, William R. 1938. Native woody plants of the United States, their erosion-control and wildlife values. Misc. Publ. No. 303. Washington, DC: U.S. Department of Agriculture. 362 p. 
43. van Melle, P. J. 1952. Juniperus texensis sp. nov. -- West-Texas juniper in relation to J. monosperma, J. ashei et al. Phytologia. 4: 26-35. 
44. Vines, Robert A. 1960. Trees, shrubs, and woody vines of the Southwest. Austin, TX: University of Texas Press. 1104 p. 
45. Wauer, Roland H. 1971. Ecological distribution of birds of the Chisos Mountains, Texas. The Southwestern Naturalist. 16(1): 1-29. 
46. Wright, Henry A.; Bailey, Arthur W. 1982. Fire ecology: United States and southern Canada. New York: John Wiley & Sons. 501 p. 
47. Zanoni, Thomas A.; Adams, Robert P. 1975. The genus Juniperus (Cupressaceae) in Mexico and Guatemala: numerical and morphological analysis. Boletin de la Sociedad Botanica de Mexico. 35: 69-91. 
48. Zanoni, Thomas A.; Adams, Robert P. 1976. The genus Juniperus in Mexico and Guatemala: numerical and chemosystematic analysis. Biochemical Systematics and Ecology. 4: 147-158.