What are mountain forests, what purpose do they serve and what happens when one is destroyed? Markus Radday, tropical forest expert at environmental group WWF has the answers.
Tanzania's Eastern Arc Mountain range runs through the entire country
What is a mountain forest?
Mountain forests make up a third of all natural forest cover worldwide. They're found on all continents with the exception of the Antarctic. They grow beyond an altitude of 500 meters. That location means mountain forests consist of trees that aren't found in lower-lying areas. The trees have adapted to the cool climate, heavy downpours and intense sunshine. In low-lying areas, they're squeezed out by different tree species. Alexander von Humboldt was the first European scientist in 1801 to describe the connection between temperatures and vegetation.
What purpose do mountain forests serve?
The most important function is in storing water and preventing erosion. Mountain forests also play an important role in the regional climate. They can absorb rainwater like a sponge. Tropical mountain forests in particular give back the collected heavy downpours in the form of water sources, streams and rivers in the surroundings, thus ensuring a uniform distribution of water throughout the year and protecting the ground from erosion. At the same time, the forests have a cooling effect and make for a balanced regional climate.
Mountain forests are home to a unique collection of plant and animal species. They include very strongly specialized species that you don't find in low-lying areas. The craggy landscape and different temperature zones also lead to different animal and plant habitats. Some of these are very small. Thus you have islands of diverse plant and animal species.
How and where are mountain forests at risk today?
Mountain forests are threatened by climate change but also by human use. People increasingly use the forests to graze cattle, collect firewood as well as for tea and coffee plantations. Mountain forests are particularly endangered in eastern Africa - in Rwanda, Burundi, Kenya, Tanzania, Ethiopia, Malawi and Uganda, in Himalayan regions such as Nepal, India and Pakistan, in the Caucasus in Armenia, Georgia and Azerbaijan, and in Laos and Cambodia in Southeast Asia. Many mountain forests have been almost completely destroyed - for instance in Caribbean states, in the Philippines and in the Mediterranean.
Did Europe have mountain forests as well?
The karstic regions in the Mediterranean ("karst" refers to a landscape shaped by the dissolution of layers of soluble bedrock - eds.,) were almost completely covered by forests in ancient times. The trees were cut down for firewood and later the forests were destroyed by fires and cattle-grazing. The vegetation there today is also home to plenty of different species but it's nowhere close to the former natural vegetation there. Despite that, the karstic regions in the Mediterranean were considered cultural landscapes which could sustain a relatively small population for centuries.
What role do mountain forests play in the fight against climate change?
Like most forests, they store vast amounts of carbon dioxide. If the forests are destroyed, the greenhouse gas is released into the atmosphere and contributes to climate change.
Author: Martin Schrader (sp)
Editor: Jennifer Abramsohn