There is a GMO topic, and I suggest that discussing that topic there would be more appropriate and not interfere with the current topic on sustainabile living.
...
Sustainable living is not just a practice for Western consumers with lots of funds, but a way for the impoverished to live in a manner that allows a minimal investment and with work provides a slow steady gain. There are regions of the world that could greatly benefit from sustainable forestry practices. Trees can produce a lot of food, medicine, prevent soil erosion, cool the region, etc. It can create a microclimate that benefits soil bacteria, insects, plants, animals, and humanity.
In many areas, villagers burn what few wood debris they can for heat and cooking fuel. By doing so, they lose all of the above benefits as well not having wood for lumber, tools, thatching, etc.
One option is using a LuciaStove. Here is a prototype. It is in Italian, but there are English subtitles. The stove does burn any organic refuse but instead burns the gases released from that organic refuse and so it produces far more heat but produces useful biochar. That leftover is a useful soil additive, can be used to improve water taste, can be altered and used as a toothpaste, can be an additive for gunpowder, etc.
http://www.youtube.com/watch?v=QsH_Gh-n2Mg
There are far cheaper ones that one can make literally with abundant scrap metal from garbage dumps. By providing villages with training, simple tools, and some mentoring, they could produce their own stoves and continue to do so, and even trade them. The more machinist work is needed, the slower the production and the more expense to it. A stove that produces similar heat and emission and biochar can be made for about $5-10 US. If scrap metal is used of course it is far cheaper.
A brick rocket stove can be made for outdoor use for pennies. We currently are teaching people to do this by making mud/straw brick, firing them in kilns, and then forming them in a pattern to produce excellent heat.
In addition, there are world-wide efforts to use solar ovens. These are literally formed with cardboard and plastic (or glass) and produce adequate heat to dehydrate food, pasteurize water, and heat up a meal. Of course this takes time and warm weather.
Because of the many parts to livestock's digestive tracts, consumed plant material becomes condensed into manure. If that dries, the smell leaves and this dried manure makes a very valuable fuel for stoves. It burns hot and clean with few emissions in a regular wood stove, but in a stove like in the youtube video, it mostly produces steam and very low emissions. While manure produces a useful fertilizer, there is an excess, so rather than contaminate the local water supply, it makes sense to use it in this manner.
Certain shrub species could be grown to burn in these stoves, then at the same time, valuable tree species could be grown to benefit the village longer term.
The most difficult aspects of sustainability is finding ways to enable the villagers to maintain current cultural practices and so not to interfere with their normal development, but to guide them with new ideas. Then to find ways that native species can be reintroduced into their region, for adding a non-native species might in the end harm their environment. Also not to create a dependancy upon Western Civilization by gifting them with some materials, but not enabling them to harvest or manufacture or mine that material in their own region.
Example: Sure there are any number of medicines that we could supply them with, but unless they have the ability to harvest the original materials and extract it, then you're only creating a dependency. The goal is to make them self-sufficient.
Example: In history, many 3rd world farmers grew polycultures of plant and animal species to put food on the dinner table. Then some people taught them that if they grew one crop, then they could sell that crop to a company, and so make a profit. The problem was with so many of their other regions growing that crop, if there was ever a glut of the crop, or a plant disease, or an insect infestation, or a natural disaster, then they couldn't feed themselves!