By Paulo Cabral
BBC Brazilian Service
In the long drought periods typical of north-eastern Brazil, the stunted, leafless and twisted trees make the Brazilian Caatinga seem a sterile and dead landscape.
"Grape growing will hardly be possible in this climate, where the hot season is also that of the rains. The same bunch will contain ripe, half ripe, and unripe berries which merely make good vinegar," wrote the Victorian explorer Captain Richard Burton, when he visited the region in 1867.
But almost 150 years on, the region is producing not only grapes - in irrigated fields - but even has a small output of reasonable quality wine.
A few drops of rain are enough for a transformation - in two or three days the plants are green once more and ready to provide food for men and animals alike.
Technology can do the same. With an efficient irrigation system towns lying in the middle of this semi-desert have turned into major fruit exporting districts, contrasting starkly with the poverty around them.
When it comes to tropical fruits, the success of the irrigation methods applied here since the 1960s is clear.
"This region produces coconut, guava, lemon, mangoes, grapes and bananas, where once there was only dry land," said Luis Bassoi, an agronomist from Embrapa, the Brazilian Agriculture Research Centre.
The most successful city in the Brazilian Caatinga is Petrolina, in the state of Pernambuco.
The town owes its success to two equally important factors: the natural fertility of its dry soil, and the action of local politicians who, in recent decades, have managed to secure the lion's share of limited irrigation resources for their constituencies.
Irrigation has made growing grapes possible where before there was only dry land
"Petrolina has been a very successful experience, but on the other hand it represents a concentration, in just one place, of wealth that should be better distributed", reads a study by the Commission for the Development of the Sao Francisco Valley (Codevasf).
"There is still quite a lot of soil suitable for irrigation within the reach of the São Francisco river, just waiting for water," Mr Bassoi conceded.
Where irrigation is not possible - or not economically viable - one solution being tried is to borrow native plants' abilities to survive in the region's hostile environment.
"The umbu tree, for instance, has long roots with plenty of space to store water and live through the harshest of droughts", said Embrapa agronomist Everaldo Rocha Porto.
The minisprinkler system avoids loss of water in the areas that really need it
"We are grafting other plants onto umbu tree roots and they are developing marvellously, despite the limited rains."
Mr Porto added that this was a possible solution for large parts of the Caatinga that cannot be irrigated due to the shallowness of the soil.
"In places where there is not much soil over the rocks, irrigating would just bring up salt and destroy the crops," he said.
However, where there is no irrigation and no finance for crops, many poor peasants are instead making a living through local drug barons by secretly growing marijuana on their lands.
Close to Petrolina, in an area where there is no irrigation, no research, no funding - but plenty of poverty - crime is thriving.
In the so-called Marijuana Polygon, drug barons finance peasants in financial difficulty to grow marijuana.
Limes - as well as guava, coconut and mango - can now be cultivated
"These peasants are not actual criminals, but poor people who have no other options," said Captain Jose Mario, chief of police in the town of Cabrobro, at the heart of the Marijuana Polygon.
"Of course we arrest these growers when we catch them, but the solution will take much more than police work.
"This is a problem caused by poverty and wealth distribution.
Mr Mario added that as a result of the drug trade, the Marijuana Polygon has become a dangerous place to be.
"In the long run these are the issues that have to be tackled," he said.
"There are robberies to pay for the marijuana crops, organised crime killings, child prostitution and a large number of guns in circulation."
Paulo Cabral travelled to north-eastern Brazil for the BBC, keeping an online journal along the way. His three-part series, Blogging in Brazil, concludes on BBC World Service, on 20th August.