Common name: Mexican cypress

Mexican cypress is an ornamental and timber-producing conifer originating in Central America, its native range limited to highland areas in Mexico, El Salvador, Guatemala, Honduras and Nicaragua. 

It may reach up to 30 m (98 ft), though it is more usually 10 to 15 m (33 to 50 ft) tall with a straight, uniform trunk. Branching starts low on the trunk on young trees, forming a pyramidal crown. As the tree ages, the lower branches shed, and the crown gradually becomes broad and flat-topped. The bark on mature trees is reddish-brown and peels off in vertical strips.

The leaves are characteristic of the Cypress family of conifers, being small, scale-like, dark green, and when crushed, give off a strongly resinous aroma.

The flowers are cones, with female and male cones borne separately on the same tree. The male cones are around 0.3 cm (0.13 in) in diameter and greenish-yellow. The female cones are larger, 1.5 cm (0.6 in) in diameter and whitish-green, becoming brown when mature and releasing winged seed dispersed by the wind. Flowering starts when the tree is about fifteen years old.

Use

Mexican cypress produces lightweight wood, weighing around 420 kgs per cubic meter (26 lbs per cubic ft), which puts it in the softwood category. Reports on its decay and termite resistance are conflicting, ranging from naturally non-resistant to very resistant. The timber is sawn into beams and planks used primarily in heavy and light construction, interior joinery, and for furniture and cabinets. Small-diameter roundwood lengths are cut for poles, posts and processing into pulp used in manufacturing fibre-board and paper products.

It responds well to pruning and is planted and maintained in gardens as a tall hedge or windbreak. It is also cultivated to produce Christmas trees for sale in the Christmas festive season, particularly in Central American and Caribbean countries.

Climate

Grows naturally in moderately humid to humid warm-temperate, subtropical and mid- to high-elevation tropical climates, generally areas with annual lows of 6 to 17°C, annual highs of 17 to 30°C, annual rainfall of 700 to 4000 mm and a dry season of 6 months or less. However, it has its best development in areas with annual rainfall of 1300 mm or more.

Growing

New plants are usually started from seed, which remain viable for several years stored under cold, dry, airtight conditions. Performs best on moist, free-draining clay and loam soils of an acid to neutral nature, generally with a pH of 5.0 to 6.5, and on sites with full to partial sun exposure. It has poor tolerance to shade and slow-draining or waterlogged soils.

Problem features

The seed can be carried on the wind over long distances and germinate readily. It is recorded as naturalised in Puerto Rico and Australia while also recorded as having escaped cultivation. However, it is assessed as a low weed risk species for Hawaii by the Hawaii Pacific Weed Risk Assessment (HPWRA) project.

Books

• Berni, C. A & Bolza, E. & Christensen, F. J. 1979, South American timbers - the characteristics, properties and uses of 190 species, Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Building Research, Highett, Victoria, Australia

• Bonner, F. T & Karrfalt, R. P. 2008, The woody plant seed manual, U.S. Department of Agriculture, Forest Service, Washington D.C.

• C.A.B. International 2013, The CABI encyclopedia of forest trees, CABI Publishing, Wallingford, Oxfordshire

• Chudnoff, M. 1984, Tropical timbers of the world, Forest Service, U.S. Department of Agriculture (USDA), Washington, D.C.

• Francis, J. K. 1998, Tree species for planting in forest, rural, and urban areas of Puerto Rico, U.S. Department of Agriculture, Forest Service, International Institute of Tropical Forestry, Río Piedras, Puerto Rico

• Francis, J. K. and Liogier, H. A. 1991, Naturalized exotic tree species in Puerto Rico, General technical report SO-82, USDA Forest Service, Southern Forest Experiment Station, New Orleans

• Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (eds). PROTA, Plant Resources of Tropical Africa, Volume 7(1) : Timbers 1, PROTA Foundation, Backhuys Publishers, Leiden

• Liegel, L. H. 1987. A technical guide for forest nursery management in the Caribbean and Latin America, U.S. Dept. of Agriculture, Forest Service, Southern Forest Experiment Station, New Orleans

• Little, E. L. & Skolmen, R. G. 1989, Common forest trees of Hawaii (native and introduced), Agricultuural Handbook No. 679, Forest Service, U.S. Department of Agriculture, Washington, D.C.

• Little, E. L. 1974, Trees of Puerto Rico and the Virgin Islands, Vol. 2, United States Department of Agriculture (USDA), Washington D.C.

• Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

• Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

• Reyes, G. 1992, Wood densities of tropical tree species, U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station, New Orleans, Louisiana

• Rowell, R. J. 1996, Ornamental conifers for Australian gardens, New South Wales University Press, Kensington, New South Wales

• Scheffer, T. C & Morrell, J. J. 1998, Natural durability of wood : a worldwide checklist of species, Forest Research Laboratory, Oregon State University, Corvallis, Oregon

• Vázquez, Y. C. 1999, Potentially valuable Mexican trees for ecological restoration and reforestation, Institute of Ecology, Database SNIB-REMIB-CONABIO, Project J084, Mexico

• Webb, D. B. 1984, A Guide to species selection for tropical and sub-tropical plantations, 2nd ed., Unit of Tropical Silviculture, Commonwealth Forestry Institute, University of Oxford, Oxfordshire