Technology: Plastic trees may turn the deserts green (NEW SCIENTIST)

SPANISH inventor Antonio Ibanez Alba claims to have developed an artificial tree which, he says, is capable of making deserts turn green within 10 years if used in sufficient numbers alongside natural trees. Several North African nations are committed to trying out the device, including Libya which is planning a pilot scheme of 30 000 to 40 000 trees.

Ibanez Alba, an electronics engineer from Barcelona, says his invention, coupled with reforestation programmes of natural trees, will turn desert areas green by changing the meteorological patterns in the desired zones, principally through the increase of precipitation. ‘If rain is caused by the meeting of cold and warm air, all you need to do is create a source of low temperatures to spark precipitation,’ says Ibanez Alba. ‘That,’ he adds, ‘in a nutshell, is what this tree is all about.’


Árboles de plástico


The tree creates cooler air by absorbing the moisture that condenses onto its surface during the cold desert nights and retaining it in the body
of the tree. During the heat of the day, the moisture is slowly released, cooling the air. The tree, which is between 7 and 10 metres tall, is the
product of four years of research and laboratory tests. It is made from fire-resistant polyurethane and phenolic foam, and imitates the stages of evaporation and condensation of a natural tree but does not require artificial or natural irrigation.

The tree, similar to its natural counterpart, is divided into three parts: roots, trunk and leaves. The stiff tubular trunk is filled with a
polyurethane material which is riddled with channels which absorb water by capillary action. The trunk contains several layers of polyurethane of different densities, designed to retain water and release it slowly during the course of the day. At the base of the trunk, for example, the density of polyurethane is 6 kilograms per cubic metre, while at the top it is 4.5 kg/m3.

 Because of the high winds in desert areas – sometimes as high as 140 kilometres per hour – the trees need strong roots. These consist of three
hollow tubes with holes along their sides arranged like a tripod at the base of the tree. After planting, polyurethane is injected into the tubes
at high pressure which oozes out into the soil to form long extrusions of polyurethane. These cool after 30 minutes and can extend up to 20 metres from the tree to give a strong anchorage.
 The branches and leaves are made from phenolic foam and are moulded to look like the crown of a palm tree, which, according to the inventor, is the most effective shape to trap dew from condensation and encourage evaporation. ‘Nature’s designs are best,’ says Ibanez Alba. Like the trunk, the branches too have varying densities.

Ibanez Alba claims that in laboratory tests the artificial tree absorbed and retained the moisture from dew and frost during the night. When dawn came, evaporation began, reaching a peak during the course of the day, and finally when the temperatures dropped in the evening, simultaneous absorption and evaporation took place.

According to Ibanez Alba, his trees would be able to retain sufficient moisture, from the condensation produced by the extreme changes in temperature (often from 70 Degree C to -5 Degree C) in these areas, to create the required cold air mass that would spark precipitation. After a few years, when the temperatures have stabilised, cloud formations from the coastal areas would be able to penetrate deep inland and release their rain over desert areas. This would start a cycle of rain patterns.

‘If we could build and plant artificial woods with millions of these trees and then sow natural trees in the same number and percentage once
the climatic changes have begun to take place, within a 10-year period the deserts could be reforested,’ explains Ibanez Alba.

The inventor believes the main advantage of his tree is that it requires no maintenance and he cites the recent case of a reforestation programme with real trees in Nigeria that failed because of the difficulty of irrigation and lack of experienced personnel. His tree is also cheap and it is not made of wood, an important source of energy in many Third World countries that would make mass plantations a temptation for locals, requiring round-the-clock vigilance.

Libya will include between 30 000 and 40 000 trees in its Pounds sterling 600 million project for the creation of an artificial river between Tripoli
and Sebha, in the south of the country.

So far Mauritania, Morocco and Algeria have also shown interest in the artificial tree. ‘If it works out,’ he says, ‘all the North African nations
and even Spain will benefit from the climatic changes the artificial forest will produce.’