Environmental motivations for migration: population pressure, poverty, and deforestation in the Philippines.

"This paper uses a multinomial discrete choice model and data from the Philippines to examine migrant choice between alternative destinations. Travel costs and perceived opportunities at the upland frontier are more important than general (upland plus lowland) destination attributes that indicate more developed social infrastructure or greater expected welfare. For example, migration streams are larger to destinations where the public share of forestland and the road system are larger. These features also characterize regions of more rapid deforestation. Therefore, emigration policies must recognize their effects on deforestation at the frontier--and their anticipated indirect effects on downstream environments."