Christopher Busch
Department of Agricultural and Resource Economics
207 Giannini Hall #3310
University of California, Berkeley
Berkeley, CA 94720-3310
Determinants of agricultural land use and forest cover in the southern Yucatán of Mexico
ABSTRACT: The paper explores the determinants of agricultural land use and forest cover in the southern Yucatán of Mexico. The setting for the study is the Southern Yucatán Peninsular Region (SYPR), an area of 22,000 square kilometers. Including contiguous forestland across the border in Guatemala and Belize, this constitutes the largest area of tropical forest outside the Amazon in the Western Hemisphere. At the center of the region is the Calakmul Biosphere Reserve, the largest tropical forest reserve in Mexico and part of the Mesoamerican Biological Corridor. About 33,500 people live in the region and are among Mexico’s most impoverished citizens. In December 2002, the Reserve was named a UNESCO World Heritage Site and this has increased the region’s profile as a laboratory for sustainable development projects.
Fieldwork was carried over a two-year time period with the core comprised of data on the collected via household survey. The data include observations on 175 households from 13 villages. The data are deep, collected over the course of three separate interviews, which yielded more than 1000 variables associated with each household. The SYPR region boundaries that define the area of study and the SYPR moniker itself are due to the NASA-funded “SYPR Project,” a large scale (more than $1 million), interdisciplinary effort. Partnership with this project provides access to a 188 household survey conducted in 1997. 149 of these 188 households were interviewed again in our 2004 survey efforts, all that still remained in the region of the original sample, thus providing greater temporal variation in our data than we could have otherwise achieved.
Broadly speaking, there is one type of land use—agriculture—and one type of land cover—forest—in the region. Thus, by understanding the determinants of agricultural land use we also understand the determinants of land remaining as forest cover. Two commercial options dominate agricultural land use, pasture for cattle and jalapeño chili peppers. However, in each case, a significant fraction chooses not to undertake the activity. In 2003, 54% of farmers had pasture for cattle and 37% of farmers had chili peppers. To account for this choice, the non-random selection into the regime, we employ a Heckman selection model to estimate (1) area in pasture for cattle and (2) area in cultivation as chili peppers. Another important agricultural land use is maize. Most households grow corn for consumption at home while only a few (24 out of 155 households) grow it for market sale. This choice structure is accounted for via a switching regression model on land area allocated to maize cultivation.
The aforementioned modeling strategy follows an existing approach in the literature, though this is the first use of the Heckman selection model to explore the region’s expanding pastureland. Previously, only chili had been thus analyzed. The paper uses discrete choice methods to develop a more nuanced understanding of the labor allocation choice across economic activities.
The results of empirical modeling, as well as direct evidence from survey responses, are consistent with theory that indicate the importance of resource constraints (labor, cash, land, soil fertility), prices (inputs and outputs), and location (transaction costs, rainfall, network effects) in determining agricultural land use area. Broadly, we conclude that pasture for cattle is on the increase because of its favorable risk profile, its low labor intensity, and increasing out-migration opportunities, whereas land area devoted to chili is on the decrease chiefly due to its high labor intensity and riskiness.