Environmental Earth Sciences

, Volume 67, Issue 4, pp 1225–1235 | Cite as

Recognizing the importance of tropical forests in limiting rainfall-induced debris flows

  • Jerome V. De Graff
  • Roy C. Sidle
  • Rafi Ahmad
  • Fred N. Scatena
Original Article


Worldwide concern for continuing loss of montane forest cover in the tropics usually focuses on adverse ecological consequences. Less recognized, but equally important to inhabitants of these affected regions, is an increasing susceptibility to rainfall-induced debris flows and their associated impacts. The same high rainfall rates that sustain tropical forest cover can often serve as the triggering mechanism for debris flows. The natural rate of debris flow occurrence on steep slopes subject to episodic, intense rainfall is dependent on the stabilizing effect of tropical forests. Either loss or significant reduction in forest cover can weaken this natural defense. Information from postdisaster observations and research on the November 1988 storm event in southern Thailand provides a case study illustrating the potential impacts of increased debris flow susceptibility resulting from conversion of forest cover to rubber tree crops. Development resulting in the loss of tropical forest cover may be accompanied by local increase in population, property development, and infrastructure. Consequently, the potentially disastrous consequences of increased debris flow occurrence are amplified by the greater vulnerability of local populations. Preserving the tropical forest cover is an obvious and often difficult means of retaining this natural protection. Effective policy should capitalize on the values of tropical forests as part of the strategy for retaining adequate forest cover. Policy should also seek to avoid creating pressures that foster forest removal or their conversion to other types of land cover in steep terrain. Areas where tropical forests were converted to other cover types can be restored to secondary forests to avoid a permanent state of increased debris flow susceptibility. Restoration of secondary tropical forests can successfully re-establish the forest characteristics that limit debris flow occurrence. Experience in Central America and the Caribbean demonstrates that successful restoration is possible but requires a significant commitment of both time and resources. In addition to the cost and technical difficulties involved, the increased susceptibility to debris flow occurrence persists through many years until successful restoration is achieved. Both retention of existing tropical forests and restoration of forest cover where loss has occurred are often justified by the reduced risk of debris flow impacts to vulnerable populations and infrastructure.


Tropical forests Debris flows Rainfall Root strength Thailand Caribbean 



This document has been reviewed in accordance with U.S Environmental Protection Agency policy and approved for publication. The authors wish to express appreciation to the reviewers of this manuscript for their positive suggestions.


  1. Abe K, Iwamoto M (1987) Soil mechanical role of tree roots in preventing landslides. In: Proceedings of 5th International conference and field workshop on landslides, Christchurch, New ZealandGoogle Scholar
  2. Ahmad R (2008) A new examination of floods in the region: debris floods and debris flows in the Caribbean. In: Baban SMJ (ed) Enduring Geohazards in the Caribbean. University of the West Indies Press, Jamaica, pp 141–156Google Scholar
  3. Ahmad R, Scatena FN, Gupta A (1993) Morphology and sedimentation in Caribbean montane streams: examples from Jamaica and Puerto Rico. Sed Geol 85:157–169CrossRefGoogle Scholar
  4. Brown S, Lugo AE (1990) Tropical Secondary Forests. J Trop Forest 6:1–32Google Scholar
  5. Caine N (1980) Rainfall intensity-duration control of shallow landslides and debris flows. Geografiska Annaler 62A:23–27CrossRefGoogle Scholar
  6. Charoenphong S (1991) Environmental calamity in southern Thailand’s headwater: causes and remedies. Land Use Policy 8:185–188CrossRefGoogle Scholar
  7. Chazdon RL (2003) Tropical forest recovery: legacies of human impact and natural disturbances. Perspect Plant Ecol, Evol syst 6:51–71CrossRefGoogle Scholar
  8. De Graff JV (1989) Landslide activity resulting from the November 1988 storm event in southern Thailand and associated recovery needs. In: safeguarding the future: restoration and sustainable development in the south of Thailand, National Operations Center, National Economic and Social Development Board and United States Agency for International Development, BangkokGoogle Scholar
  9. De Graff JV (1990) Landslide dams from the November 1988 storm event in southern Thailand. Landslide News 4:12–15Google Scholar
  10. De Graff JV (1992) Increased debris flow activity due to vegetative change. In: Bell DH (ed) Landslides: Proceedings of the Sixth International Symposium on Landslides. Christchurch, NZ. A. A. Balkema, Rotterdam, pp 1365–1373Google Scholar
  11. De Graff JV, Ochiai H (2009) Rainfall, debris flows and wildfires. In: Sassa K, Canuti P (eds) Landslides: disaster risk reduction. Springer-Verlag, Berlin, pp 451–471CrossRefGoogle Scholar
  12. De Graff JV, Bryce R, Jibson RW, Mora S, Rogers CT (1989) Landslides: their extent and economic significance in the Caribbean. In: Brabb EE, Harrod BL (eds) Landslides: Extent and Economic Significance. Proc A A Balkema, Rotterdam, pp 51–80Google Scholar
  13. ESCAP (1989) ESCAP technical assistance to the flood affected areas in southern Thailand. Mission Report, United Nations Economic and Social Commission for Asia and the Pacific, BangkokGoogle Scholar
  14. Finegan B (1996) Pattern and process in neotropical secondary rain forests: the first 100 years of succession. Tree 11:119–124Google Scholar
  15. Fischer A, Vasseur L (2000) The crisis in shifting cultivation practices and the promise of agroforestry: a review of the Panamanian experience. Biodiv Conserv 9:739–756CrossRefGoogle Scholar
  16. Garcia-Montiel DC, Scatena FN (1994) The effect of human activity on the structure and composition of a tropical forest in Puerto Rico. For Ecol Manag 63:57–78CrossRefGoogle Scholar
  17. Grau HR, Aide TM, Zimmerman JK, Thomlinson JR, Helmer E, Zou X (2003) The ecological consequences of socioeconomic and land-use changes in postagriculture Puerto Rico. Bioscience 53:1159–1167CrossRefGoogle Scholar
  18. Gray DH, Megahan WF (1981) Forest vegetation removal and slope stability in the Idaho Batholith. USDA Forest Service Research Paper INT-271, Ogden, UtahGoogle Scholar
  19. Greenway DR (1987) Vegetation and slope stability. In: Anderson MG, Richards KS (eds) slope stability. John Wiley and Sons, New York, pp 187–230Google Scholar
  20. Haigh MJ, Jansky L, Hellin J (2004) Headwater deforestation: a challenge for environmental management. Glob Environ Chang 14(Suppl 1):51–56Google Scholar
  21. Haldemann EG (1956) Recent landslide phenomena in the Rungwe volcanic area. Tanganyika. Tanganyika Notes Rec 45:3–14Google Scholar
  22. Harp EL, Reid ME, McKenna JP, Michael JA (2009) Mapping of hazard from rainfall-triggered landslides in developing countries: examples from Honduras and Micronesia. Eng Geol 103:295–311CrossRefGoogle Scholar
  23. Harper SB (1993) Use of the approximate mobility index to identify areas susceptible to landsliding by rapid mobilization to debris flows in southern Thailand. J Southeast Asian Earth Sci 8:587–596CrossRefGoogle Scholar
  24. Harper SB (1996) Debris flows triggered by the November 1988 rainstorm in Phipun District, Nakhon Si Thammarat Province, southern Thailand. Dissertation. University of Georgia, AthensGoogle Scholar
  25. Holl KD, Loik ME, Lin EHV, Samuels IA (2000) Tropical montane forest restoration in Costa Rica: overcoming barriers to seed dispersal and establishment. Rest Ecol 8:339–349CrossRefGoogle Scholar
  26. Imaizumi F, Sidle RC (2007) Linkage of sediment supply and transport processes in Miyagawa Dam catchment, Japan. J Geophysical Res Earth Surf. 112. doi:10.1029/2006JF000495
  27. Jan C-D, Chen C-L (2005) Debris flows caused by Typhoon Herb in Taiwan. In: Jakob M, Hungr O (eds) Debris-flow hazards and related phenomena. Praxis Publishing, Chicester, pp 539–563CrossRefGoogle Scholar
  28. Jones FO (1973) Landslides in Rio de Janeiro and the Serra das Araras escarpment, Brazil. U.S. Geological Survey Professional Paper 647Google Scholar
  29. Kongrattanachok P (2005) Carbon sequestration in cassava and para rubber plantation, Rayong Province. MS thesis, Mahidol University, ThailandGoogle Scholar
  30. Lanly JP (1969) Regression de la Forest Dense en Cote d’ Ivoire. Bois For Tropiques 127:45–59Google Scholar
  31. Lopez-Rodriguez SR, Blanco-Libreros JF (2008) Illicit crops in tropical Amercia: deforestation, landslides, and the terrestrial carbon stocks. Ambio 37:1–3CrossRefGoogle Scholar
  32. Martin PH, Sherman RE, Fahey TJ (2004) Forty years of tropical forest recovery from agriculture: structure and floristics of secondary and old-growth riparian forests in the Dominican Republic. Biotropica 36:297Google Scholar
  33. Ministry of Agriculture, Planning and Environment (2000) The Commonwealth of Dominica’s first national report on the implementation of the United Nations Convention to combat desertification. Commonwealth of Dominica, Roseau, WIGoogle Scholar
  34. Moran MD (2006) Diversity and complexity. In: Spray SL, Moran MD (eds) Tropical Deforestation. Rowman and Littlefield Publishers, Oxford, pp 1–24Google Scholar
  35. Nakane K (1995) Soil carbon cycling in a Japanese cedar (cryptomeria japonica) plantation. Forest Ecol Manage 72:185–197CrossRefGoogle Scholar
  36. Niiyama K, Kajimoto T, Matsuura Y, Yamashita T, Matsuo N, Yashiro Y, Ripin A, Kassim Abd, Rahman Noor, Supardi Nur (2010) Estimation of root biomass based on excavation of individual root systems in a primary dipterocarp forest in Pasoh Forest Reserve Peninsular Malaysia. J Tropical Ecol 26:271–284CrossRefGoogle Scholar
  37. Nilaweera NS, Nutalaya P (1999) Role of tree roots in slope stabilization. Bull Eng Geol Environ 57:337–342CrossRefGoogle Scholar
  38. Panayoutou T, Ashton PS (1992) Not by timber alone: economics and ecology for sustaining tropical forests. Island Press, Washington DCGoogle Scholar
  39. Phien-wej N, Nutalaya P, Aung Z, Zhibin T (1993) Catastrophic landslides and debris flows in Thailand. Bull Int Assoc Eng Geol 48:93–100CrossRefGoogle Scholar
  40. Restrepo C, Alvarez N (2006) Landslides and their contribution to land-cover change in the mountains of Mexico and Central America. Biotropica 38:446–457CrossRefGoogle Scholar
  41. Restrepo C, Walker LR, Shiels AB, Bussman R, Claessens L, Simey F, Lozano P, Negi G, Paolini L, Poveda G, Ramos-Scharron C, Richter M, Velazquez E (2009) Landsliding and its multiscale influence on mountainscapes. Bioscience 59:685–698CrossRefGoogle Scholar
  42. Rosenqvist A, Murai S, Vibulsresth S (1990) Flood damage analysis in southern Thailand. Proceedings of the 23rd International Symposium of Remote Sensing of Environment, Bangkok, Thailand, ERIM, Ann Arbor, MI, pp 315–324Google Scholar
  43. Scatena FN, Lugo AE (1995) Geomorphology, disturbance, and the soil and vegetation of two subtropical wet steepland watersheds of Puerto Rico. Geomorphology 13:199–213CrossRefGoogle Scholar
  44. Scatena FN, Planos-Gutierrez EO, Schellekens J (2004) Natural disturbances and the hydrology of humid tropical forests. In: Bonell M, Brunijnzeel LA (eds) Forests, Water and People in the Humid Tropics. Cambridge University Press, Cambridge, pp 5–28Google Scholar
  45. Sidle RC (1991) A conceptual model of changes in root cohesion in response to vegetation management. J Environ Qual 20(1):43–52CrossRefGoogle Scholar
  46. Sidle RC (2005) Influence of forest harvesting activities on debris avalanches and flows. In: Jakob M, Hungr O (eds) Debris-flow Hazards and Related Phenomena. Praxis Publishing, Chicester, pp 387–409CrossRefGoogle Scholar
  47. Sidle RC (2010) Hydrogeomorphic processes: the role of bioclimatic factors, land use, and scale. Geog. Compass 2(6):1–18. doi:10.1111/j.1749-8198.2010.00350.x Google Scholar
  48. Sidle RC, Ochiai H (2006) Landslides: Processes, Prediction, and Land Use. American Geophysical Union, Washington, DC, p 312CrossRefGoogle Scholar
  49. Sidle RC, Ziegler AD, Negishi JN, Nik AR, Siew R, Turkelboom F (2006) Erosion processes in steep terrain—truths, myths, and uncertainties related to forest management in Southeast Asia. For Ecol Manag 224:199–225CrossRefGoogle Scholar
  50. Starkel L (1972) The role of catastrophic rainfall in the shaping of the relief of the lower Himalaya (Darjeeling Hills). Geogr Polonica 21:103–147Google Scholar
  51. Stokes A, Atger C, Bengough AG, Fourcaud T, Sidle RC (2009) Desirable plant root traits for protecting natural and engineered slopes against landslides. Plant Soil 324:1–30CrossRefGoogle Scholar
  52. Turkelboom F (1999) On-farm diagnosis of steepland erosion in northern Thailand. Unpublished Ph.D. Thesis. Faculty of Agricultural and Applied Biological Sciences, K.U. LeuvenGoogle Scholar
  53. Wieczorek GF, Glade T (2005) Climatic factors influencing occurrence of debris flows. In: Jakob M, Hungr O (eds) Debris-flow Hazards and Related Phenomena. Praxis Publishing, Chicester, pp 325–362CrossRefGoogle Scholar
  54. Wieland M (1989) Effects of floods of November 18-23, 1988 in southern Thailand on highway bridges and large dams. Report, Division of Structural Engineering and Construction, Asian Institute of Technology, BangkokGoogle Scholar
  55. Ziemer RR (1978) An apparatus to measure the crosscut shearing strength of roots. Can J For Res 8(1):142–144CrossRefGoogle Scholar
  56. Ziemer RR (1981) Roots and the stability of forested slopes. In: Davies TRH, Pearce AJ (eds) Erosion and Sediment Transport in Pacific Rim Steeplands. IAHS, Christchurch, pp 343–361Google Scholar

Copyright information

© Springer-Verlag (outside the USA)  2012

Authors and Affiliations

  • Jerome V. De Graff
    • 1
  • Roy C. Sidle
    • 2
  • Rafi Ahmad
    • 3
  • Fred N. Scatena
    • 4
  1. 1.USDA Forest ServiceClovisUSA
  2. 2.Ecosystems Research Division, National Exposure Research Laboratory, Office of Research and DevelopmentUSEPAAthensUSA
  3. 3.Mona Geoinformatics Institute, Unit for Disaster StudiesUniversity of the West IndiesKingstonJamaica
  4. 4.Department of Earth and Environmental ScienceUniversity of PennsylvaniaPhiladelphiaUSA

Personalised recommendations