The causes of deforestation are numerous and vary considerably with the particular context at hand. Despite this some general statements can be made. The actors involved are invariably loggers, farmers or cattle ranchers, and the way in which their activities determine land use and deforestation is governed by the prevailing institutions, markets and sometimes policies. Chief among the institutional determinants are property rights, e.g. to land and timber, and their enforcement. Of the many economic determinants, the nature of land markets, local labour markets and in and out migration are key. Where institutions are weak and markets fail to reflect the full economic value of standing forest, which due to global concern for climate change and biodiversity conservation are in large part held globally, cause for concern is warranted.