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This new report from FAO and CIFOR challenges the conventional wisdom linking large-scale flooding to deforestation. The report acknowledges that forests can play a role in minimising runoff that causes localised flooding. But it concludes that there is no evidence that a loss of trees significantly contributes to severe widespread flooding. Even at the local level, the report notes, the flood-reducing effects of forests are heavily dependent on soil depth and structure, and saturation levels, not exclusively on the presence of the trees. Instead the authors believe that the sharp increase in the economic and human losses attributed to flooding is caused not by deforestation but mainly by the simple fact that more people are living and working in flood plains. As a result, many floods that previously would have been only minor events now become major disasters.The authors go on to claim that there can be a political interest in leaving the conventional wisdom about forests and floods unchallenged. For example, they say, it allows governments to simply respond with logging bans and give the appearance to the public they are taking decisive steps to stop flooding. The practical effect of such policies is to force poor farmers—who are routinely portrayed as major perpetrators of "illegal logging"— to abandon their lands. They give as examples the catastrophic floods in China, Thailand and the Philippines which prompted logging bans that put millions of people out of work. Furthermore international agencies may also have a stake in maintaining the forest-flood "myth", according to the report, as it helps in "channelling aid funds to upland reforestation projects."The FAO and CIFOR state that it is time for national and international policy makers and development agencies to acknowledge that objective scientific research does not provide easy answers when it comes to understanding flooding. Instead, they point to a complex interplay of natural and man-made conditions that produce major floods and exacerbate their impact. For example, the report notes that large floods always have been a natural—and beneficial—part of the ecosystem. But a range of human activities, such as draining and developing wetlands and damming and altering stream flows, can make them worse. They call for an integrated approach which recognises the limitations of working only in the uplands to minimise floods or only in the lowlands to reduce their damage. Such an approach combines land-use management in the uplands with land-use planning, engineering measures, flood preparedness and emergency management in the lowlands. Crucially, they say, it considers the social and economic needs of communities living in both the mountainous watersheds and the river basins.
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Major floods 'not linked to deforestation'
http://www.scidev.net/News/index.cfm?fuseaction=readNews&itemid=2414&lan...
There is no evidence to support claims that deforestation causes large-scale flooding, says a report by international forestry and agriculture organisations.
