The world lost three percent of its total forested area between 1990 and 2005. With rising concern over the identification of deforestation determinants, increasing efforts are being made to understand the relationship between roads and deforestation. However, the effect of roads on forests is ambiguities. In many instances roads are found to lead to deforestation, while some notable contrary findings are also existed.

Recently, a research group in the Institute of Geographic Sciences and Natural Resource Research(IGSNRR), Chinese Academy of Sciences(CAS), led by Professor DENG Xiangzheng  published a paper with a title of “Pressure Cookers or Pressure Valves: Do Roads Lead to Deforestation in China?” in Journal of Environmental Economics and Management to address the impacts of road building on the deforestation in China.

The researchers takes Jiangxi, one of the most forested provinces in China, as a case study area, by using satellite remote sensing data to track changes over time at the one square kilometer pixel level, aiming at the coupling mechanism of the forest cover change between 1995 and 2000 and the roads presence(or size) in 1995.

With both standard OLS with covariates and two covariate matching methods— “covariate matching using an inverse variance weighting scheme” and “covariate matching using a Mahalanobis weighting scheme”, holding constant a set of carefully defined geographic and climatic factors; demographic and economic variables, distance variables and other factors, the project found that there is no evidence to indicate that roads contributed to deforestation. When roads were either widened or improved or when roads penetrated into a watershed, they did not appear to be adding any pressure to the forests. If anything, there is weak evidence that roads relieved a bit of pressure off the forests. The perhaps reason for this can be concluded as when an area is long settled, and when population densities are fairly high, it is possible that when roads enter an area (or are improved), they can act as a way to reduce the cost of moving out of the region or reduce the cost of technologies that will encourage more intensive cultivation/use of land resources in non-forested areas.