Environmental deterioration as a cause for Mayan collapse

Aside from the climate-based theories for the collapse of the Classic Maya are those that deem environmental deterioration, as a result of rising population densities, as a major cause. It is said that such ecological mismanagement would have led to reduced productivity of the agricultural system, which in turn would have been largely responsible for the depopulation of urban centres. Among these, deforestation has occasionally been cited as a playing a major role.

Deforestation is the long-term reduction in the aerial extent of arboreal forest through the removal of tree species, either for the trees themselves or four some other resource(s) associated with the forest (Oldfield, 1981, p. 280). It is necessary for the rate of removal to exceed the rate of regrowth in order to be considered as deforestation.

The link between deforestation and the collapse of the Mayan empire was first alluded to by Cooke (1931), who stated that the rate of soil erosion was enormously accelerated when forest was cut and the cultivated soil was exposed to the torrential rains. This model gained support over the years, but the first empirical evidence was presented by Sanders (1973). Studying an area of Guatemala, he found that over 40% of soils had high to very high susceptibility to erosion and of these 37% had high fertility and thus attractive to an expanding agricultural system. It was added that these soils are found in areas which, prior to cultivation, were covered with forest. Despite this evidence for the link between deforestation and agricultural decline, however, the rate, absolute chronology and specific causes of ecological deterioration remained unclear. Furthermore, it remained necessary to qualify the relationship between agricultural decline and demographic collapse.

Shimkin (1973) suggested that the eventual shortages of fuel wood, necessary for heating and cooking, may have led to increased endemic respiratory and gastrointestinal diseases, contributing to a higher mortality rate and local population decline. 

References

Cooke, C. W. (1931). 'Why the Maya Cities of the Peten District, Guatemala, were abandoned.' Journal of the Washington Academy of Sciences 21(13): 283-287.

Oldfield, M. L. (1981). 'Tropical deforestation and genetic resources conservation.' In Sutlive, V. H., Altshuler, N., and Zamora, M. D. (eds.), Blowing in the Wind: Deforestation and Long-Range Implications. Studies in Third World Societies Pub. 14, College of William and Mary, Virginia, pp. 277-346.

Sanders, W. (1962). Cultural ecology of the Maya lowlands (Part I). Estudios de Culture Maya 2: 79-121.

Shimkin, D. B. (1973). 'Models for the downfall: Some ecological and culture-Historical considerations.' In Culbert, T. P. (ed), The Classic Maya Collapse. University of New Mexico Press, Albuquerque, pp. 269-299.