Large-scale tree felling is detrimental to both the ecosystem and the livelihoods of farmers. They are now taking matters into their own hands and have set up a jungle patrol.

"Un kilo de ayuda" ("A kilo of help") is now a household name in Mexico. Donors contribute by rounding up their bills at supermarket check-outs. Ávalos's efforts for this good cause have earned him the Schwab Foundation's Social Entrepreneur award.

He loves barbecue sandwiches, is a keen explorer and wants people to become more environmentally aware.

Banco del Tiempo is a "time bank" that works on the basis of account holders earning credit for hours worked; essentially, this means they exchange services such as ironing, interior decorating, sewing and babysitting.

The bank, set up by the non-profit organisation Civica, opened its first branch a year ago, and now there are already five.

The chemical fertilisers that could help to replenish the fields are too expensive for most farmers. The "Zaï" technique presents a cheaper and greener alternative. It increases the water retention capacity of soil with the aid of what are not usually man's best friends: termites.