Tropical Montane Cloud Forests (TMCFs) are special places created by specific processes. They are found in the tropics, at mid-altitude on the windward slopes, where the clouds intersect with the mountains. The persistent cloud cover over the canopy of the forest maintains the high annual precipitation (500–1000 mm) and humidity. It also ameliorates intense sunlight, maintaining a mean temperature of 12–23°C.
Because of their specific environmental needs, TMCFs are naturally fragmented, much of their original extent has already disappeared and current protected areas are poorly placed with respect to the future distribution of cloud forest under climate change. Due to their high biodiversity and endemism, TMCFs are considered among the most threatened ecosystems of the world.
In Mexico, TMCFs are limited to a narrow strip between 600 and 3000 metres above sea level in the main mountain ranges, covering around 0.8% of the region. They are characterized by an archipelagic distribution and high biodiversity containing some 10% of all Mexican plant species and 12% of all Mexican terrestrial vertebrates with many endemic taxa.
Under conservative climate change scenarios it has been estimated that in Mexico suitable areas for TMCF will decrease by up to 70% by 2080. However, if cloud forest outside of current protected areas is transformed for other land-uses such as agriculture (and there are many examples of this), less than 1% of TMCF might remain (see Decision Point #58).