Sunday, January 26, 2014

Road Construction, Deforestation, and Land Use in Belize

Chomitz, K. M., & Gray, D. A. (1996). Roads, land use, and deforestation: a spatial model applied to Belize. The World Bank Economic Review10(3), 487-512.

This article examines the relationship between distance from markets in Belize, road construction, and the likelihood of road construction and land use. The authors contend that while road construction has many economic and social benefits of connecting the rural poor to more urban centers, there are also great environmental drawbacks. This is largely seen through deforestation, loss of biodiversity, and climate change. According to Chomitz and Gray, Belize is facing rapid population growth. With this, there is an increase in slash and burn agriculture. As a result, the authors assert that the impact of building roads in these rural areas must be quantified in order to see the full tradeoff between economic development and environmental preservation (Chomitz and Gray 487)

In order to conduct this study, the authors used “spatially explicit framework” in order to show variation that is not present in aggregate data and location, such as the physical extent of deforestation and the effect on habitats and watersheds (Chomitz and Gray 488).  The authors developed a spatial model of land use following the ideas of von Thünen that assumed land use would occur where the output was greater then input  (490). A sample of land points south of the Western Highway in Belize was used, which yielded 11, 712 data points for the study. These points were collected via geographic information systems methods. SPOT satellite imagery from 1989 to 1992 was used to collect the data along with field data. Nine variables where used to analysis the data (nitrogen percentage, slope, available phosphorus, pH, wetness, flood hazard, rainfall, national land, and forest reserves). Additionally, the distance to the markets was computed by the cost of transport and the slope of the region. The land use was classified into three categories- semi-subsistence agriculture, commercial agriculture, and natural vegetation- to help analyze the results and create a dependent variable of type of land use (Chomitz and Gray 495).  

The study suggests that land quality, market distance, and tenure, strongly suggest type of cultivation, likelihood, as well as probability of road construction (Chomitz and Gray 501). For example, the study found that for every 0.1 percent increase in nitrogen, there was 24-33 percent decrease in distance to a market, suggesting that higher soil quality increases the likelihood of cultivation and thus road construction (Chomitz and Gray 500). This model also allowed the authors to study the type of agriculture that occurs in variation to distance from markets and road availability. For example, the study found that semi-subsistence and commercial agriculture decrease as one progresses away from markets (Chomitz and Gray 500). Due to these findings, the authors’ advocate for greater consideration to be taken by planners in terms of agriculture and road construction due the variety of variables involved as well as environmental and economic trade off. 

Caitlin Schneider


  1. Unless it's very obvious and I missed it, why did the study only focus on this area of Belize? What's going on in the North? This is interesting, and it'd be cool to also take ecotourism and cattle ranching practices into account. I think the brand of analysis that takes localities into account makes sense when you're talking about so many kinds of variables.

  2. A very interesting article about economic development and environmental degradation. A future project may want to examine the effects of a road on commercial activity. If roads increase commercial activity and urban sprawl, then the government of Belize may want to regulate this activity through zoning codes to preserve the environment. The study may also want to research what kind of economic activity is generated by road construction, i.e. gasoline stores, housing development, restaurants, ecotourism, etc. A cost-benefit-analysis may reveal that the cost of road construction outweighs its benefits because not enough economic activity is generated once the road is constructed; therefore, planners should not go a road-building binge that will quicken environmental destruction.