Comments on: Rewarding and regulating the upland poor http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/ New perspectives on mainland Southeast Asia Mon, 23 Nov 2009 15:28:26 +1100 http://wordpress.org/?v=2.8.4 hourly 1 By: James Haughton http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/comment-page-1/#comment-7104 James Haughton Tue, 14 Nov 2006 13:03:42 +0000 http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/#comment-7104 The role of forests in averting floods must be getting a lot of consideration in Thailand at the moment. What's the consensus (if there is any) on that? The role of forests in averting floods must be getting a lot of consideration in Thailand at the moment. What’s the consensus (if there is any) on that?

]]> By: Andrew Walker http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/comment-page-1/#comment-6786 Andrew Walker Sun, 12 Nov 2006 21:02:02 +0000 http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/#comment-6786 Thanks Ross, there is a large literature on the hydrological functions of forest. I am very familiar with Nipon's work. While there is considerable uncertainty there are, I think, three key points that emerge from the literature: 1. Forests are large water users. Forest clearing will increase annual stream flow given the reduction in evapo-transpiration (ET) following clearing. 2. The effect of forest clearing on dry season water flow is more uncertain, given that this is determined by the balance between the impact of reduced ET and the impact of possible reduction in soil infiltration. 3. Forest planting is likely to reduce dry season flow given that the short-term and medium term impact in terms of increased ET is likely to greatly outweigh slight (and slow) improvements in infiltration. I have written about these issues at length in 'Forests and water in northern Thailand" Chiang Mai University Journal 1(3). Available at: http://cmuj.chiangmai.ac.th/full/2002/sep2002-2f.pdf Thanks Ross, there is a large literature on the hydrological functions of forest. I am very familiar with Nipon’s work. While there is considerable uncertainty there are, I think, three key points that emerge from the literature:

1. Forests are large water users. Forest clearing will increase annual stream flow given the reduction in evapo-transpiration (ET) following clearing.
2. The effect of forest clearing on dry season water flow is more uncertain, given that this is determined by the balance between the impact of reduced ET and the impact of possible reduction in soil infiltration.
3. Forest planting is likely to reduce dry season flow given that the short-term and medium term impact in terms of increased ET is likely to greatly outweigh slight (and slow) improvements in infiltration.

I have written about these issues at length in ‘Forests and water in northern Thailand” Chiang Mai University Journal 1(3). Available at:

http://cmuj.chiangmai.ac.th/full/2002/sep2002-2f.pdf

]]> By: Ross Pengilley http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/comment-page-1/#comment-6717 Ross Pengilley Sun, 12 Nov 2006 13:16:45 +0000 http://asiapacific.anu.edu.au/newmandala/2006/11/10/rewarding-and-regulating-the-upland-poor/#comment-6717 Andrew, See Nipon Tangtham The Hydrological Roles of Forests In Thailand Published in TDRI Quarterly Review Vol. 9 No. 3 September 1994, pp. 27-32 -on the web. and the work done by CSIRO[Paul Redell and others] in North Queensland on the hydrology of tropical forests-brief summary on the web. Andrew,
See

Nipon Tangtham The Hydrological Roles of Forests In Thailand
Published in TDRI Quarterly Review
Vol. 9 No. 3 September 1994, pp. 27-32 -on the web.

and the work done by CSIRO[Paul Redell and others] in North Queensland on the hydrology of tropical forests-brief summary on the web.

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