Deforestation dries out cloud forest

Cloud forests in the mountains of Central America are being dried out by deforestation in adjacent lowlands, according to a group of US researchers who used satellite pictures to study tropical cloud forests in Costa Rica and Nicaragua.

The forests — and the unique plants and animals that live in them — depend on prolonged immersion in cloud, which is formed when warm winds blowing off the Caribbean are forced upwards by the mountains, cool and condense.

But the researchers found that where lowland forests have been cleared, the clouds that support the mountainous forests do not appear. Water evaporating between the trees normally reduces the air temperature. In its absence, air is warmer and has to be lifted higher before it cools into mist.

Reference: Science 294, 584-587 (2001)