Conquistadors, wars, slavery and syphilis won’t help, of course, but cutting down all of your trees is asking for trouble. And yet this is still happening all over the world, notably in Indonesia, where giant swathes of virgin rainforest are being felled and replaced with monoculture crops (specifically the oil palm), and in Brazil and Africa.

In a worrying recent development, a global forestry treaty, REDD (Reducing Emissions from Deforestation and Forest Degradation), due to be signed at the Copenhagen climate change conference this December is set to allow countries to cut down virgin rainforest, plant monoculture crops such as soy and palm oil, call the results forest, and even claim millions in funding for their preservation. Only if essential safeguards preventing deforestation in favour of monoculture crops is restored will the treaty serve to prevent deforestation, instead of effectively subsidising it.

But why is deforestation such a bad idea? We’ve all been hearing about deforestation for years, but what actually happens, why is it so disastrous, and how does deforested land turn into desert?

No two situations are the same, but here are some of the things that happen when you cut down all of your trees:

Habitat fragmentation

Fragmented habitats - an aerial view of an area deforested by soybean farmers. Image: Greenpeace

Habitat fragmentation is what happens when the preferred physical and biological environment in which an organism or group of organisms live  (their habitat) is broken up. This creates more ‘edge’ or boundary areas with non-preferred habitats, reduces the size of habitats, and alters the micro-climate of each fragmented pocket of habitat. Species immediately become more vulnerable.

Habitat fragmentation in tropical forests is primarily caused by deforestation. Deforestation may be performed for logging, agriculture or rural development, or as a consequence of activities such as oil exploration, mining, road building, and dam construction. Tropical forest habitats may also be fragmented in the longer term by geological or climate change, but the blame for deforestation usually lies at our door.

Species extinction and human cost

Species which would usually avoid living at the edge of their habitat are at greater risk of predation by other species that may avoid venturing within the forest, including humans. The ‘edge effect’ may also increase competition for food and other resources, and a change in microclimate at the habitat edge may cause exposure to higher temperatures and winds, all with less shade and protection. The edge effect is exacerbated the more fragmented the habitat is – like the coast of Norway, there is exponentially more ‘edge’ as time goes by.

Orangutans are reluctant to leave their habitat even if it is destroyed around them. Image: Orangutan Foundation

Habitat fragmentation leads to smaller habitats, increasing competition for resources, creating a scarcity of some resources and having potentially a far greater impact if species within the food web die off and in turn starve dependant species. Finally, smaller populations of species in fragmented habitats are more susceptible to extinction through decreased genetic diversity and disease.

Assessing the vulnerability of a species within a fragmented forest habitat is difficult, as different species of different sizes have different space requirements, and so may be more or less susceptible to habitat fragmentation and reduced size. Some species may also have a symbiotic relationship with partner species within a habitat which, if lost, will be disastrous for them. Finally, some species simply emigrate to alternate habitats – if you have legs and wings, and you’ve run out of food, it’s time to move.

But this doesn’t always happen. Orangutans are unwilling to leave the canopy even if they’re perched at the top of the last tree in the forest. It also goes without saying that humans affected by deforestation and changes to their habitat may simply have nowhere to go. Tribes may not be able to move for economic, political or social reasons. There are many examples of tribes who, having been displaced from their traditional lands, with no source of income and no means of subsistence, fall into a downward spiral of alcoholism, drug use and despair. Right now, the Ayoreo-Totobiegosode tribe, one of the last uncontacted tribes outside the Amazon, are losing their land to beef production.

Soil erosion and desertification

Exposure to higher temperatures and winds at the habitat edge, without the benefit of plant cover and root systems due to the damage to plant species, leads to soil erosion. In the case of most rainforest environments, the nutrients needed for plant and animal life to continue are stored in the canopy, not the ground. Felling and burning the forest leaves soil bereft of nutritional value, unable to support the vegetation that would bind it together and regulate moisture. Crops grow only with the intensive use of fertilizers, polluting watercourses and causing eutrophication (a buildup of algal plant life which chokes all other plant life).

This erosion has the potential to encroach ever further into fragmented forest habitats, increasing fragmentation and eventually leading to desertification, wiping out entire habitats and driving plant and insect species to extinction. An entire habitat may also be at risk from changes in water flows due to erosion, flooding and increased river levels. Changes in wider climate such as precipitation levels may indiscriminately affect the entire habitat, including the interior.

The Nasca and us

The Nasca disappeared around 1500 years ago, and the recent Cambridge University study suggests that a significant factor in their demise was their destruction of the huarango trees that played such an important role in regulating soil moisture and nutrients. The Nasca, in their drive to plant more crops and to build, destroyed their own environment.

World population in the time of the Nasca was around 300 million. It is now over 6.5 billion. The landscape has changed beyond recognition, but the mistakes the Nasca made are being repeated now, on an exponentially wider scale. What’s different now is that we in the Western world are witnessing the destruction of other tribes, species and environments, to maintain ours. Tribes like the Ayoreo-Totobiegosode, and species like the orangutan, are more vulnerable than the Nasca ever were, because they are shouldering the burden of our consumption.

More info and actions:

• Uncontacted tribe’s forest bulldozed for beef – write a letter to the President of Paraguay
• Support the Orangutan Foundation campaign ‘Protect me and my tree’
• Palm oil – rainforest in your shopping (Friends of the Earth)
• Important safeguards to protect rainforests lacking in REDD negotiating text
• Boreal forests store twice as much carbon as tropical – so why aren’t we doing more to protect them?

Related posts:

1. REDD A fascinating article on the Washington Monthly website by (I...