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w orldwatch n Reforestation leads to the export of deforestation: Efforts to conserve forests in many developing nations has led to deforestation in other countries, according to a new study published in the Proceedings of the National Academy of Sciences.

team led by Patrick Meyfroidt of the Catholic University of Louvain in Belgium analysed the relationship between reforestation at the national scale and international trade in forest and agricultural products between 1961 and 2007, focusing on six developing countries that underwent a shift from net deforestation to net reforestation during that period: China, Chile, Costa Rica, El Salvador, India and Vietnam.

With the exception of India, in all of these countries, the return of native forests was accompanied by a reduction in timber harvests and the creation of new farmland over the same period, thus creating demand for imported wood and agricultural products. According to the study, this meant that for every 100 hectares of reforested land, the equivalent of 74 hectares of forest products were imported. Taking into account the countries’ exports of agricultural products, the net imbalance came to 22 hectares of land used in other countries. But during the past five years, that figure rose to 52 hectares, so for every hectare of land reforested, half a hectare was used elsewhere.

‘If local forest protection merely shifts forest-conversion pressure to natural forests elsewhere in the world, we won’t achieve a net gain for nature at a global scale,’ said one of the study’s authors, Eric Lambin. ‘However, this study doesn’t imply that the efforts of these countries to protect their forests was useless, but that international trade in wood and agricultural products can decrease the global environmental benefits of national forest-protection policies.’

West/Alamy im

Vacant lots could feed Detroit A new study by researchers at Michigan State University suggests that transforming vacant urban lots in Detroit into farms and community gardens could satisfy the majority of the city’s residents’ fruit and vegetable needs.

The collapse of Detroit’s manufacturing industry and subsequent urban flight has left the city with large areas of vacant land. As part of the study, the researchers catalogued available land without existing structures. Using aerial imagery and the city’s database of vacant property, they identified more than 44,000 available parcels of land, covering an area of almost 2,000 hectares. This land, if turned over to a combination of urban farms, community gardens, storage facilities and hoop houses – greenhouses used to extend the growing season – could satisfy three quarters of the local demand for vegetables and 40 per cent of the demand for fruits, the researchers calculated.

‘What’s clear from our analysis is that even with a limited growing season, significant quantities of fresh fruits and vegetables eaten by Detroiters could be grown locally,’ said Kathryn Colasanti, the graduate student who led the study, which was published in the Journal of Agriculture, Food Systems, and Community Development. ‘And investments in produce storage facilities and hoop houses would increase this capacity substantially.’

In brief

MAURITANIA Scientists have discovered an extensive cold-water coral ecosystem off the coast of Mauritania. Located on the continental shelf at a depth of around 615 metres, the coral wall is 50–60 metres high and 190 kilometres long.

ICELAND Results from a genetic study of a family in Iceland suggest that the first Americans arrived in Europe 1,000 years ago. The researchers who carried out the study have hypothesised that a particular set of genes found in the family arrived in Iceland when an Amerindian woman was taken from North America by the Vikings some time around 1000 AD.

AFRICA Health campaigners have expressed optimism that meningitis could soon be brought under control in Africa thanks to the development of a cheap vaccine. The vaccine, which costs 30p a dose to produce, was developed by the World Health Organization and Seattle-based non-profit group Path.

PANAMA The Panama Canal and Panama City are at risk of a devastating earthquake, according to new research. As part of a seismic-hazard study in preparation for the expansion of the canal, researchers found evidence that two faults that pass under it are seismically active and last ruptured in a large earthquake in 1621.

MEDITERRANEAN Scientists have traced the distinctive red ‘terra rossa’ soil found around the Mediterranean in places such as Mallorca and Sardinia to the Sahara and Sahel. The dust appears to have been blown over the region between 12,000 and 25,000 years ago.

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