The initial plan involved digging (by hand) water retention trenches all over these barren hillsides to capture the monsoon waters and feed them into the groundwater.  Everyone was pleased that the initial plantings of trees and vegetation did well - until it became clear that the need for animal fodder and the value of trees for lumber and fuel caused entire hillsides to be deforested and overgrazed in years two and three after planting.  The stories of how WOTR developed community support for protecting the trees, how that led to a huge change in the way women interact with their communities, the effects on the economy as well as the huge environmental success of these village based projects is well worth the read.  

The long and short of it is that planting trees, recovering desert lands and poverty alleviation can go hand-in-hand, but it isn't quite as easy as just planting a tree.  But it includes planting trees.  Interdependence and interaction between humans and ecosystems is the name of the game.  In the long run, supporting the whole eco-system can also alleviate poverty.  As Grist would say, "Duh."


smsweitzer

"... bubble-bursting critics point out, large-scale tree-planting will only help the climate cause if the location and types of trees are carefully considered."

This is a very serious matter if we want more than a feel-good activity and are actually interested in reducing global warming, reducing loss of threatened habitats, and increasing biodiversity.

We desperately need a central database regarding exactly which trees should be planted and where they should be planted. I'll use my own experience as an example. If I simply go to one of the websites devoted to encouraging the planting of trees and type in my ZIP code, I will get an enormous list of suggestions that include invasive Eurasian species, invasive native species (i.e., there is no shortage of them anywhere), and very inapproriate species (i.e., not naturally found within hundreds of miles of my home ). I wonder how many people accept that information and go purchase a few trees for their backyard.

I chose to consult a local university herbarium website (http://wisplants.uwsp.edu/WisPlants.html) and carefully checked every tree for exactly where it naturally grows in Wisconsin, whether it is native, whether it is invasive, and whether it is appropriate for the soil around my home. This is not unusual behavior for me... I become a bit obsessed with certain projects. But how many people invest this much in selecting trees? Anyway... this left me with about 30 trees to choose from. I further narrowed the list by considering wildlife value. I'd like one more piece of information: Which ones sequester the most carbon? But I'm having trouble finding that bit of info. By the way, I did the same thing to come up with a list of shrubs.

Now... zoom out and consider what's involved in planting a billion trees around the globe in all sorts of environments, perhaps displacing current flora, but hopefully being done to reclaim barren ground or prevent erosion. Who is deciding which trees should be planted? I certainly hope it isn't someone running a nursery; they are going to push the most-profitable and easy to grow trees. Who is deciding where the trees should be planted? Are local ecologist making the decision? If some organization is going to start a campaign to encourage individuals to plants trees, are they going to ensure that people are sufficiently informed to actually make a difference as far as climate and biodiversity is concerned?

It is never a good idea to just do something, even if it isn't necessarily the right thing. We don't have the resouces for feel-good environmentalism. People need some direction.

Thus, it would be nice if there was a central database regarding exactly which trees should be planted and where they should be planted. It might be set up like Wikipedia so ecologists could add to it. Governments and NGOs could go to it for information that would guide tree-planting activity. Problems -- such as planting a tree that harms local flora and fauna -- could be identified, discussed, and solved before they spiral out of control. Those funding tree-planting activity could easily identify which regions to focus on... where tree-planting will really make a positive difference. Activists could set up programs to educate people and raise money for where it is needed.

If this already exits, I hope someone will let me and others know about it.

What kind of wildlife can survive in a forest that consists of one type of tree?  How long will it be before one strain of disease or bug wipes out an entire forest?  

It's even worse than a single-species problem.  Where seedlings are produced from cuttings from a small number of trees, there is essentially a very limited number of individual organisms in the forest, making them even more susceptible to disease.

geobeck