Want clean water? Save your forests!

Cities can ensure they have a cheap and abundant supply of clean water by protecting and regenerating forests in their surrounding watersheds, according to a major analysis just undertaken in Malaysia.

Forests are a vital source of clean water -- and important for lots of other reasons too.

Forests are a vital source of clean water -- and important for lots of other reasons too.

Jeffrey Vincent from Duke University, USA and his colleagues have just published the largest cost-benefit analysis ever conducted in the tropics, and they find that pristine and even selectively logged forests are very cost-effective ways to produce clean, drinkable water. 

Vincent and colleagues ran their analyses under a wide range of scenarios.  They used as a baseline the costs of standard water-treatment plants, which are often required to make polluted water safe to drink.

The authors found that the relative advantages of forests depend on local circumstances, with the financial benefits being greater in some situations than others. 

Also, if one factors in profits that can be made by exploiting the forests -- such as by converting them to agriculture -- then the numbers could change. 

The problem, of course, is that waters that drain off of agricultural lands are often polluted by fertilizers, pesticides, and organic wastes, making expensive water-treatment necessary.

The authors argue that, beyond water purification, intact forests have many other financial and non-financial values. 

For instance, they store large stocks of carbon, and thereby reduce greenhouse gas emissions. 

They also can harbor enormous biodiversity while helping to attract substantial income from ecotourism.  Remarkably, it's currently estimated that protected areas across the world attract some 8 billion visits annually, underscoring their financial value for local communities.

Furthermore, via the process of evapotranspiration, forests emit enormous quantities of water vapor.  For example, one-third to one-half all the rainfall that falls on a tropical forest is quickly recycled back to the atmosphere, as water vapor.

This water vapor (plus natural organic aerosols emitted from forests) help to form clouds, which in turn reflect solar radiation back into outer space, thereby reducing global warming. 

Forests are natural cloud-makers.

Forests are natural cloud-makers.

Such clouds also help to produce life-giving rainfall during the dry season -- when forests are most drought-stressed and prone to fires.

Finally, forests are very good at reducing destructive floods.  They tend to act like giant biological sponges, trapping water and releasing it slowly, thereby reducing downstream flooding.  Especially in areas where forests are denuded, flooding can cause billions of dollars in damage and costs thousands of lives each year.

The conclusion: It's increasingly becoming apparent that it's smart to conserve pristine and selectively logged forests -- even when one uses just hard, cold economic logic. 


Crisis time for India's endangered forests

The Western Ghats—a long mountain chain that supports ancient rainforests and a range of other habitats—is arguably India’s most biologically important real estate.  Here, ALERT member Jean-Philippe Puyravaud weighs in on the ongoing debate about how best to conserve this critical region:

Debate ahead for imperiled forests...

Debate ahead for imperiled forests...

Two ambitious management plans, by the Western Ghats Ecology Expert Panel and the High Level Working Group, were recently proposed for the Western Ghats.  Both attempted to identify Ecologically Sensitive Areas (ESAs) that merit protection, but generally got a cold reception from stakeholders and the general public.  

A recent article in Mongabay argues that these management schemes represent a way forward, so why haven't they been better received?

Both plans were invited to make conservation choices based on the principle of sustainability.  But the Indian Ministry of Environment and Forests, which contracted the studies, failed to define what “sustainability” meant.  Because this basic definition was muddy, there was no clarity about anything else--the development model for the region, or which industries or livelihoods would be favored in a reasonable path to prosperity.

The legal framework for the ESA scheme wasn't clear either.  Whether the ESA overrides existing laws or competes against them at the local level is yet to be seen.  For instance, plans to protect elephant corridors may be diluted by the scheme.

Without any clear economic guidelines, both the Western Ghats Ecology Expert Panel and High Level Working Group framed their own understanding of how the Western Ghats should be managed economically and legally.  This was probably an overshoot of their mandates.

What this tells me is that society’s reactions to conservation plans may not imply a lack of enthusiasm about conservation.  In the ESA case, widespread confusion on several levels created so much public angst that neither plan had much chance of widespread acceptance.

Where should roads go and not go?

Mongabay.com is highlighting our current efforts to devise a 'global road-map' that identifies where on Earth new roads should and should not go.

Roads in intact forests or other frontier areas often open a Pandora's Box of environmental problems, such as increasing deforestation, logging, fires, hunting and illegal mining.

Roads can bring big environmental problems--a logging truck in Borneo (photo by Rhett Butler).

Roads can bring big environmental problems--a logging truck in Borneo (photo by Rhett Butler).

In our analysis, areas that should remain road free have high values for wilderness, biodiversity, carbon storage, and climate regulation.  Protected areas are also priority road-free zones.

Areas that would benefit from new or improved roads include regions that have already been settled but have low agricultural productivity.  In such areas, road improvements can increase access to markets, fertilizers, and farming technologies, raising agricultural production.  As farm production rises, these areas can act as 'magnets' for settlers, drawing them away from vulnerable frontier areas and thereby reducing pressures on native ecosystems.

The global road-map is seen as an urgent priority, as highlighted in a recent Nature paper by myself and Andrew Balmford.  The International Energy Agency estimates that 25 million kilometers of new roads will be added to the Earth by 2050.  Around 90% of these will be in developing nations, which harbor much of Earth's imperiled biodiversity.

-Bill Laurance    

Are vines taking over the world?

Most types of vines like forest disturbances, so it's not very surprising to see vines proliferating in logged, fragmented and regenerating forests.  And in warmer parts of the world, many introduced vine species are proliferating; the aggressive kudzu vine, for instance, has rapidly colonized much of the southeastern US.

But it's less apparent why vines should be increasing in intact, undisturbed forests.  That is precisely what researchers are now finding, across a number of sites in the tropics.  In a recently accepted paper in Ecology, for instance, my colleagues and I found that woody vines (lianas) have increased by about 1% per year over the last 14 years in old-growth rainforests in central Amazonia.

Why are vines on the rise?  In our paper we consider some of the leading hypotheses for this puzzling environmental mystery.

-Bill Laurance

Woody vines (lianas) and trees are ancient enemies.  

Woody vines (lianas) and trees are ancient enemies.