While we were researching forests, we came across a number of ecosystems that can occur within that type of biome.  Now, every biome has a vast span of diversity and forests are no different, but one just jumped out as fascinating: the alpine montane forest, also known as the cloud forest.

By User DirkvdM on en.wikipedia - Photograph by Dirk van der Made (en:User:DirkvdM - for more photos see en:user:DirkvdM/Photographs)., CC BY 1.0, Link

As you might have surmised, these forests have some sort of relationship with clouds.  They do, as they generally occur at altitudes that clouds can form or where fog is a frequent occurrence within the habitat.  For those of you who have checked out our page on the Hydrosphere, you'll know this is special, as clouds are water in its vapor form.  But why is this special, you may ask?  Clouds are a part of life on Earth, all forests have to deal with cloud cover.

When we say altitudes that clouds form, however, we mean that the forests aren't covered by clouds.  They are within the clouds!  And due to this unique closeness to water vapor, these forests are highly specialized in absorbing water from the air.  That's right, this forest loves pulling water from clouds without the need for the cloud to precipitate.  Where other forests have to depend on delivery, these wonders can pull straight from the source.  Like we said, fascinating!​

Location Location Location

Getting the conditions right for a cloud forest is mostly about location.  Not just latitudinal and longitudinal, but also from an altitude perspective, which does depend a bit on the former.  The general altitude range for North, South, and Central America is between 2,000 and 3,500 meters, with some exceptions in Central America appearing as low as the 500 to 1,000 meter range.  Africa and Asia's cloud forests generally range from altitudes of 1,000 - 3,000 meters.​

Or course, this can vary widely from region to region as geographic location and altitude only get the ecosystem so far.  It also demands favorable hydrology and climate, both of which can fluctuate immensely in the anthropocene era.

These regions are so specific that they only make up 0.85% of the Earth's total forest and woodland cover as of around the year 2000.  That is undoubtedly lower now with forests, in general, losing land coverage since then.  To put it in perspective, forests, as of 2010, have covered 30% of the Earth's landmass, cloud forests specifically only accounting for 0.25% of the entire landmass, and deforestation continues at alarming rates.  They truly are rare and only getting rarer.

Cloud Forests get their name from their relationship with clouds.  They really are forests in the clouds!

Diversity

Cloud forests, by their nature, are wet habitats.  Most of which occur in a tropical climate, though some can reach into more temperate zones.  As was the case with tropical forests, these ecosystems are home to dense biodiversity.

The wetness mentioned is primarily a result of the plants that grow in this habitat.  Undoubtedly a keystone species, though more of a group of species, is epiphytes, or plants that grow on other plants, surfaces, or substrates.  These are our mosses, orchids, lichens, etc.  What makes these plants so key to the ecosystem is their ability to pull water from vapor in the clouds that deluge the forest.

Epiphytes, like mosses, can pull water from the clouds engulfing the forest, providing fresh water without rain

Mosses, for example, are non-vascular plants (meaning that they don't have systems for moving nutrients around the plant, like roots).  To cope with this, they are very well-equipped to gathering and storing water through their leaves.  Water that does not get absorbed will trickle down the surface that the plant is situated on, eventually delivering the water to the ground.  Now, since mosses can't move nutrients up the plant via root system, they tend to be small anyways.  When we say "eventually" it really isn't that long of a wait given the plant's structure.

​The lushness granted by the habitats amazing ability to pull water from air gives way to an astounding array of bird species as well as the wild forms of plants that we know in our household today.  This includes things like the tomato, avocado, blackberry, cucumber, and potato.  Suffice to say, despite the exactness of the needs for this ecosystem to thrive, a lot of plants and animals call it home!

Social Dependency

As if the biodiversity and general ecosystem functions weren't enough, these environments also exhibit unique social dependencies for humans living around them.  As mentioned earlier, wild variants of common food items can be found in these forests in addition to plants and herbs historically used for medicinal purposes.  Unfortunately, as the case is for the medicinal plants, these have come under exploitation from the environment, rather than caring for a sustainable approach to harvesting them.  Surprisingly (or unsurprisingly if you recall that these forests tend to appear at high altitudes), exploitative timber extraction isn't as big of an issue, though it is still done.

One of the sustainable resources, and arguably the biggest social dependency, is that of a dry season watershed.  Since the forest is capable of pulling water from vapor, any water that trickles to the ground not absorbed into the ground will find its way to streams.  These streams provide a dependable source of fresh water to communities that otherwise wouldn't have any during dry seasons.  If there is a community around a cloud forest, you can almost guarantee that they'll be downstream of the forest to capitalize on this feature of the environment! 

Preserving a Threatened Ecosystem

Water aside, as over-exploitation would actually drive away communities neighboring the forests, these ecosystems are subject to some of the same dangers as other forests in the world.  Timber extraction, while more difficult to do, is still done especially on the forest fringes.  The most common reasoning is to make way for farmland.  One of the key ways to combat this is to adopt more socio-economic agricultural practices, taking advantage of the trees benefits rather than uprooting them.

Human communities depend on the forest's unique watershed, living along streams that flow even in dry seasons thanks to its ability to pull water from clouds

hePlant poaching and game hunting in tandem with continued shrinking of the forest area results in an issue known as fragmentation.  This can have multiple meanings, one of which is more straightforward in that humans can cut off a part of the forest from the main area.  This accentuates the other meaning which applies to wildlife having their domain reduced, not letting them populate the area they're used to.  This really lets other animals, nest predators for example, take advantage of prey not being able to build homes in protective environments.  This may seem like nature at work, but unfettered success of the predator leads to a lack of food causing the predator to either migrate or die.  Without the balance the ecosystem offered, this fragmentation can lead to behaviors that lead to unintended extinctions.

Climate change is another interesting one for cloud forests.  This impacts the world at large, but as the planet heats up, it makes the areas that these forests reside less habitable.  The tree line will start to move to find the "sweet spot" for the forest's endemic life.  To a point, at least.  As these forests occur at high altitudes, as temperatures rise, so must the forest.  And the higher you go, the less ground you have to cover.  It can literally push these forests to a point where they have nowhere to go until they go through a succession leading to a change in habitat.  Not many habitats face this type of scenario, but cloud forests must cope with this in addition to the typical chaos introduced to areas impacted by climate change.

Digressions aside, this topic was one that just really jumped out to us while we were researching and we really wanted to share this ecological marvel of an ecosystem with you.  We will, no doubt, continue to be inspired to do more of these as we learn more about the world around us, so hopefully you've enjoyed taking a bit of time to learn about one of our home's most unique ecosystems and are encouraged to go out there, learn more, and share with your friends as well :)

~ And, as always, don't forget to keep wondering ~

Sources
* Global Forest Watch. “Tree cover in ”. Accessed on 28/03/2020 from www.globalforestwatch.org.

* Bubb, P., May, I., Miles, L., Sayer, J. 2004 Cloud Forest Agenda. UNEP-WCMC, Cambridge, UK.
Online at: http://www.unep-wcmc.org/resources/publications/UNEP_WCMC_bio_series/20.htm

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