Chicle: a Sustainable Rainforest Crop

Introduction Chicle, Manilkara zapota, is a New World rainforest tree with a long history of human use (Simpson & Ogorzaly, 1995). Common names include: sapodilla, naseberry, nispero, chico-sapote, sapotier, zapote, and zapotillo. This species suppies edible fruit, timber, and most importantly, the chicle latex base for chewing gum (WWW, 1997).

Taxonomy and Diversity The Sapotaceae family (Magnoilopsida: Dilleniidae: Sapotales) is a diverse and ecologically important family of 700 species and 35 or 40 poorly defined genera (Takhtajan, 1997; Shultes & Raffouf, 1990). These shrubs and trees are widely distributed pantropically (Shultes & Raffouf, 1990). This family is easily recognized by the combination of milky latex and alternate (spiral) leathery leaves with parallel secondary and tertiary veins (Gentry, 1993).

The genus Manilkara includes 30 New World and 32 Old World species, several of which are economically important as sources of latex, fruit, and timber. The flowers are distinctive due to a two-whorled calyx of three sepals each, the outer valvate, and the open corolla having lobes three-parted to near the base, sometimes the lateral lobes divided again to give up to 30 segments (Gentry, 1993). Manilkara zapota (L.) Royen is native to southern Mexico, Guatemala, Belize, and Nicaragua. It is also found in El Salvador, although the native status is uncertain, as it is widely cultivated in the tropics (WWW, 1997) Chicle is an evergreen tree of lowland rainforests that grows to 38 meters in height (Roecklein & Leung, 1987). This species is one of the 10 most important dominant species of Mexican rainforests, both in terms of frequency and in terms of food resources for mammals and birds (Toledo, 1982).

Human Uses and Economic Importance Manilkara zapota is primarily a source of the latex called chicle. The prevalence of this species in rainforests in the Yucatan and Guatemala that were once Mayan agricultural areas may reflect ancient encouragement, if not cultivation, of chicle (Mabberley, 1992). Chicle was not widely known until 1867, when an American inventor named Thomas Adams attempted to create a rubberlike material from chicle that was supplied by the exiled Mexican general Santa Anna. The chicle could not be used like rubber, but Adams added sugar to chicle pellets, and sold it as chewing gum (Simpson & Ogorzaly, 1995). Chicle remained the main base for the immensely popular chewing gum until 1944-1945 when it was replaced by petroleum-derived synthetics (Schwartz, 1990). During the intervening 75 years, U.S. manufacturers monopolized the product by financing chicle tapping in Mexico and Central America. By 1930 these companies were importing 15 million pounds of chicle a year, and their products were sold worldwide (Schwartz, 1990).

The chicle tappers, called chicleros, live in temporary camps. Chicleros move daily into the forest to find the wild chicle trees. These rarely reach densities of 25 to 30 trees per hectare. For complex reasons related to the nature of tropical forests, efforts to cultivate this species in plantation stands have failed (Schwartz, 1990). The chicle latex is drained from ducts in the inner bark layers of the tree by making zigzag cuts in the bark with a machete (Kricher, 1989). Chicleros say that after initial tapping, the tree must be allowed to rest for four to five years before being retapped. Some five to fifteen percent of tapped trees are killed each tapping season by being cut too deeply (Schwartz, 1990). The exuded latex is collected, molded into blocks, and shipped for processing. A small amount of chewing gum is still made with chicle (Simpson & Ogorzaly, 1995).

M. zapota also bears a soft, sweet fruit that is a favorite in tropical America. The fruit is eaten fresh, used to flavor ice cream, and made into syrup and jam. The hard wood from this tree is used to make various articles and for lumber (Roecklein & Leung, 1987). Some medicinal uses have been recorded among the Nahua Indians of Peten Guatemala, who call the plant chichiltzapotl . Juice of the fruit was taken as a tea to combat fatigue or anemia (Orellana, 1987).

Conclusion

Manilkara zapota is an example of an important nontimber (mostly) forest product of tropical America, as a source of the chicle latex base for chewing gum (Balick & Cox, 1996). Although chicle is no longer a popular source of gum, the growing realization that petroleum products are nonrenewable and probably not healthful may swing opinion back in chicle’s favor. Pressure for renewable organic products should assist in this movement. Fruits and latex can represent more than 90 percent of the total market value of tropical forests, over time far exceeding the value of timber or conversion to pasture (Peters et al, 1989). Hopefully, chicle will become both a more popular sustainable-use rainforest product, and another reason to preserve the rainforest.

Literature Cited

Balick, M.J. and P.A. Cox. 1996. Plants, people, and culture: the science of ethnobotany. Sci. Amer. Library, New York.

Gentry, A.H. 1993. A field guide to the families and genera of woody plants of northeast South America. Conservation International. Washington, D.C.

Kricher, J.C. 1989. A neotropical companion. Princeton Univ. Press, New Jersey.

Mabberley, D.J. 1992. Tropical rainforest ecology. 2nd. ed. Chapman and Hill, Inc., New York.

Orellana, S.L. 1987. Indian medicine in highland Guatemala. Univ. of New Mexico Press, Albuquerque.

Peters, C.M., A.H. Gentry, and R.O. Mendelsohn. 1989. Valuation of an Amazonian rainforest. Nature. 339:655-6.

Roecklein, J.C. and P.S. Leung. 1987. A profile of economic plants. Transaction, Inc., New Brunswick, New Jersey.

Schwartz, N.B. 1990. Forest society: a social history of Peten, Guatemala. Univ. of Pennsylvania Press, Philadelphia.

Shultes, R.E. and R.F. Raffauf. 1990. The healing forest: medicinal and toxic plants of the northwest Amazonia. Dioscorides Press, Portland, Oregon.

Simpson, B.B. and M.C. Ogorzaly. 1995. Economic botany: plants in our world. 2nd.ed. McGraw-Hill, Inc., New York.

Takhtajan, A. 1997. Diversity and classification of flowering plants. Columbia Univ. Press, New York.

Toledo, V.M. 1982. Pleisotcene changes of vegetation in tropical Mexico. In: G.T. Prance, editor. 1982. Biological diversification in the tropics. Columbia Univ. Press, New York. Internet Reference http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?102614 Chicle: a Sustainable Rainforest Crop

by Amanda Neill

2 December, 1997

BOTN 328 Dr. Wilson

Economic Botany Term Paper