Arizona Cypress

Basic Information
Tree ID: 
Genus and species: 
With branches broader and more open than many other species of juniper, the Arizona Cypress is often used as a windbreak tree and can be found in western Texas, the southern High Plains, and the arid American Southwest, where it can tolerate the hot, dry conditions (1). The Arizona Cypress var. arizonica grows 20-25 m tall with a diameter of up to 75 cm (10). The tree is sometimes cultivated for use as a Christmas tree (2)
Sophia Yin, Matthew Wrocklage
Collected Data
Tree shape: 
High-density columnar, pyramidal
Date of tree entry: 
6.80 m
Diameter at breast height: 
0.18 m

The Arizona Cypress's peeling brown bark turns gray with age (1). The bark of the variety C. arizonica var. arizonica becomes fibrous as the tree ages, exhibiting flat ridges and longitudinal furrows (2). The Arizona cypress variety C. arizonica var. glabra (smooth cypress) has smooth, cherry-red bark that exfoliates annually in thin layers (10). Image credit for C. arizonica var. glabra: Stang, D. "Cupressus arizonica Greene." (Sept. 14, 2005). In: "Cupressus arizonica." Accessed April 24, 2018. Used under Creative Commons. License details at:
Twigs & branches
The branches of the Arizona Cypress generally grow upright and avoid drooping (1). Across different specimens, branches range from dense to somewhat openly branched (10). Branchlets decussate, or occur in cross-like distributions (7). Twigs can be described as "cord-like" or "four-sided" (2). When grown as an ornamental tree, the twigs are especially susceptible to damage by the cypress bark beetle (2).
The tree's foliage, while green, exhibits a silvery-gray or blue shimmer (1). The tree's simple, scale-like leaves grow to a length of less than 2 inches (1). Leaves have a notable "pitlike" abaxial gland that creates resin drops (4). Leaves are opposite and occur in pairs (7). In the variety C. arizonica var. arizonica, leaves are about 2 mm long, sharply acute, and are keeled or ridged on their back side (10).
Reproductive Structures
The Arizona Cypress is a monoecious conifer. Seed cones are 3/4 to 1 inch in diameter, appearing dark reddish-brown and round in shape (2). The seed cones have 6-8 shield-shaped woody scales (2). Seed cones mature in autumn of the second season, but persist on the tree for many years (2). Within the cones of the Cupressaceae family, the cones' bract-scale complexes are fused for much of their length (6). Seed cones occur with 3-4 pairs of scales, either smooth or with scattered resin blisters (5). On apical scales, a conic knob or umbo can sometimes be observed (5). Seeds are generally 4-6 mm in length and of a light tan or dark brown coloration (5). Pollen cones within the Cupressaceae family mature and shed annually, occuring as solitary and terminal cones (6). Within the pollen cones, sporophylls generally overlap, bearing 2-10 pollen sacs. The pollen grains are spherical, not winged (6). The Arizona Cypress' pollen cones generally contain 4-6 pollen sacs (5). For cultivation, C. arizonica seed is collected from cones in autumn. Seedlings have 3-5 cotyledons (10).
The dry and hard "fruit", the fertilized female cone, is round in shape, growing from 0.5 to 1 inch in length (1). Please see reproductive structure section for greater detail on the structure of the female cone.
  • Winter: February.
  • Winter: Frost-resistant leaves covered in ice.
  • Spring: April.
Natural range of distribution: 
The Arizona Cypress tree's native distribution stretches from the western US to north-western Mexico, especially including the dry mountain areas of Arizona, New Mexico, Texas, and northern Mexico (10). The Arizona Cypress occurs only in the upper Sonoran life zone and within the lower borders of the arid transition zones (10). Though the Arizona Cypress is found naturally on rocky mountain slopes and on canyon walls, the tree can also be planted in better, more well-irrigated soils (2). The tree can particularly be found on ridges and slopes with north-east to north-west exposure (10). Drought-tolerant, the tree requires 10-12 inches of water annually and cannot tolerate soils with a high water table. The Arizona Cypress generally cannot tolerate elevations beyond 3,000 feet, and requires full sunlight for best growth (2). The Arizona Cypress can tolerate a variety of soil types, including loam, sand, acidic, alkaline, and well-drained soils (1). C. arizonica vars. arizonica and glabra are both tolerant of winter and spring frost and do not show damage due to sulfur dioxide or hydrogen fluoride pollutants, making them tolerant of planting even in industrial areas (10). Information for distribution map gathered from USDA PLANTS Database page (3).
Origin, history, and uses: 

The Cupressaceae family has a known fossil record dating back to the Jurassic period (6).  The family to which the Arizona Cypress belongs is a diverse one, often divided between Cupressaceae in its strictest sense (having leaves opposite in four ranks, or whorled) and Taxodiaceae (with alternate leaves), though the family is best considered a single, unified grouping (6).  The Arizona Cypress has a sporophytic chromosome count of 22 (5).  

While the tree is generally regarded as a poor source of timber given its knottiness and tendency to split while drying, the Arizona Cypress can be grown and processed for use as fence posts, due to its durability when seasoned properly (2, 10).  The tree is sometimes used for Christmas trees, hobby/craft items, or as windbreaks in windswept desert areas (2).  Because of its dense foliage and acidic litter, the tree covers the soil completely and is thus planted to reduce weed coverage and fire risk (10).  

The Arizona Cypress is an evergreen tree that retains leaves across seasons and experiences no fall color change (1). For the family Cupressaceae, pollination usually occurs in late winter or in spring (6). Seed maturation occurs in late summer or autumn (6). Specifically, the cones of the Arizona Cypress mature in autumn of the second season, but persist on the tree for several years (2).
  1. Gilman, E.F., & Watson, D.G. (1993).  Fact Sheet ST-222: Cupressus arizonica var. arizonica: Arizona Cypress.  Accessed April 23, 2018.  
  2. “Plant Fact Sheet: Arizona Cypress, Cupressus arizonica Greene.”(n.d.) USDA Natural Resources

    Conservation Service. Accessed April 23, 2018.  

  3. Plant Profile: Hesperocyparis arizonica, (Greene) Bartel, Arizona Cypress (n.d.).  USDA Natural Resourcse Conservation Service. Accessed April 23, 2018.  

  4. Eckenwalder, J.E. 1993. Cupressus arizonica Greene [family CUPRESSACEAE].  Flora of North America North of Mexico, (vol. 2), Provisional Publication.  July 23, 2012.… Accessed April 24, 2018.  

  5.  Greene, E.L. (1882) “Cupressus arizonica Greene.”  Missouri Botanical Garden.  Accessed April 23 2018.  

  6. Watson, F.D., & Eckenwalder, J.E. (1993).  “4. Cupressaceae Bartlett: Redwood or Cypress Family.”  Flora of North America, vol. 2.  Accessed April 24, 2018.  

  7. Eckenwalder, J.E. (1993) “4. Cupressus​”. Flora of North America, vol. 2. Accessed April 24, 2018.  

  8. Kinsella J, 1963. Windows. Poems 1980-1994. Newcastle upon Tyne: Bloodaxe Books; 1998:172.

  9. Kinsella J. Native Cut Wood Deflects Colonial Hunger. Poetry. 2015(Mar.),….  Accessed April 24, 2018.

  10. Cupressus arizonica. The CABI Encyclopedia of Forest Trees. 2013.

  11. Khouaja W, Oliveira R, Raies A, Dias ACP. Antifungal activity of the essential oils from Cupressus arizonica var. arizonica and var. glabra. Industrial Crops and Products. 2015;77:614-623.

Other information of interest: 

The tree is susceptible to bagworms and can be affected by Juniper blight, particularly in humid and cool regions (1). Additionally, a “stem canker” has been known to damage large populations of the trees in certain regions of the country, resulting from the “cypress canker disease”, a pathogenic fungus known as Seridium cardinale (1, 10).  Further threats to the tree include rusts and mistletoes, as well as the cypress aphid, Cinara cupressi (2, 10).  

As noted already, two major varieties of C. arizonica exist, namely C. arizonica var. arizonica and C. arizonica var. glabra,  both of which are monoecious (10). More broadly, however, the Arizona Cypress is referred to by botanists by a variety of names.  Between different botanists, various accepted names are Callitropsis arizonica and Hesperocyparis arizonica, though a number of other names can refer to the same tree​ (5).  The tree has been commonly referred to in China as “Iu gan bai” (5).  

Interestingly, the essential oils of both var. arizonica and glabra​ have antifungal activity against pathogenic yeasts of the genus Candida (11).  In the var. glabra, this activity occurred even at incredibly low concentrations (11).  

The tree is guarded in Nevada under the protected category of “Cactus, Yucca, or Christmas tree” (3).

Some report that the tree’s branches emit an unpleasant odor if crushed (2).  

Media and Arts

The Arizona Cypress is featured in the poem Windows by John Kinsella, a work featured in a 1998 collection Poems (8).  Kinsella, an Australian poet, highlights the landscape of Western Australia in his creative works and has treated themes of colonialism and environmental exploitation in his writing, as noted in another of his poems Native Cut Wood Deflects Colonial Hunger (9). A link to that poem, available for free on the Poetry Foundation’s website, is included here.  

The painting created for this project was inspired by the verses of Kinsella’s poem Windows.