Contradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling

Persistent Link:
http://hdl.handle.net/10150/618979
Title:
Contradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling
Author:
Lacombe, Guillaume; Ribolzi, Olivier; de Rouw, Anneke; Pierret, Alain; Latsachak, Keoudone; Silvera, Norbert; Pham Dinh, Rinh; Orange, Didier; Janeau, Jean-Louis; Soulileuth, Bounsamai; Robain, Henri; Taccoen, Adrien; Sengphaathith, Phouthamaly; Mouche, Emmanuel; Sengtaheuanghoung, Oloth; Tran Duc, Toan; Valentin, Christian
Affiliation:
Univ Arizona, Grad Coll
Issue Date:
2016-07-08
Publisher:
COPERNICUS GESELLSCHAFT MBH
Citation:
Contradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling 2016, 20 (7):2691 Hydrology and Earth System Sciences
Journal:
Hydrology and Earth System Sciences
Rights:
© Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License.
Collection Information:
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
Abstract:
The humid tropics are exposed to an unprecedented modernisation of agriculture involving rapid and mixed land-use changes with contrasted environmental impacts. Afforestation is often mentioned as an unambiguous solution for restoring ecosystem services and enhancing biodiversity. One consequence of afforestation is the alteration of streamflow variability which controls habitats, water resources, and flood risks. We demonstrate that afforestation by tree planting or by natural forest regeneration can induce opposite hydrological changes. An observatory including long-term field measurements of fine-scale land-use mosaics and of hydrometeorological variables has been operating in several headwater catchments in tropical southeast Asia since 2000. The GR2M water balance model, repeatedly calibrated over successive 1-year periods and used in simulation mode with the same year of rainfall input, allowed the hydrological effect of land-use change to be isolated from that of rainfall variability in two of these catchments in Laos and Vietnam. Visual inspection of hydrographs, correlation analyses, and trend detection tests allowed causality between land-use changes and changes in seasonal streamflow to be ascertained. In Laos, the combination of shifting cultivation system (alternation of rice and fallow) and the gradual increase of teak tree plantations replacing fallow led to intricate streamflow patterns: pluri-annual streamflow cycles induced by the shifting system, on top of a gradual streamflow increase over years caused by the spread of the plantations. In Vietnam, the abandonment of continuously cropped areas combined with patches of mix-trees plantations led to the natural re-growth of forest communities followed by a gradual drop in streamflow. Soil infiltrability controlled by surface crusting is the predominant process explaining why two modes of afforestation (natural regeneration vs. planting) led to opposite changes in streamflow regime. Given that commercial tree plantations will continue to expand in the humid tropics, careful consideration is needed before attributing to them positive effects on water and soil conservation.
Note:
Open Access Journal
ISSN:
1607-7938
DOI:
10.5194/hess-20-2691-2016
Version:
Final published version
Sponsors:
French watershed network SOERE-RBV (reseau des bassins versants); French Observatory for Sciences of Universe (Observatoire des Sciences de l'Univers); CGIAR research program on Integrated Systems for the Humid Tropics; French ANR TECITEASY [ANR-13-AGRO-0007]
Additional Links:
http://www.hydrol-earth-syst-sci.net/20/2691/2016/

Full metadata record

DC FieldValue Language
dc.contributor.authorLacombe, Guillaumeen
dc.contributor.authorRibolzi, Olivieren
dc.contributor.authorde Rouw, Annekeen
dc.contributor.authorPierret, Alainen
dc.contributor.authorLatsachak, Keoudoneen
dc.contributor.authorSilvera, Norberten
dc.contributor.authorPham Dinh, Rinhen
dc.contributor.authorOrange, Didieren
dc.contributor.authorJaneau, Jean-Louisen
dc.contributor.authorSoulileuth, Bounsamaien
dc.contributor.authorRobain, Henrien
dc.contributor.authorTaccoen, Adrienen
dc.contributor.authorSengphaathith, Phouthamalyen
dc.contributor.authorMouche, Emmanuelen
dc.contributor.authorSengtaheuanghoung, Olothen
dc.contributor.authorTran Duc, Toanen
dc.contributor.authorValentin, Christianen
dc.date.accessioned2016-08-27T00:52:31Z-
dc.date.available2016-08-27T00:52:31Z-
dc.date.issued2016-07-08-
dc.identifier.citationContradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling 2016, 20 (7):2691 Hydrology and Earth System Sciencesen
dc.identifier.issn1607-7938-
dc.identifier.doi10.5194/hess-20-2691-2016-
dc.identifier.urihttp://hdl.handle.net/10150/618979-
dc.description.abstractThe humid tropics are exposed to an unprecedented modernisation of agriculture involving rapid and mixed land-use changes with contrasted environmental impacts. Afforestation is often mentioned as an unambiguous solution for restoring ecosystem services and enhancing biodiversity. One consequence of afforestation is the alteration of streamflow variability which controls habitats, water resources, and flood risks. We demonstrate that afforestation by tree planting or by natural forest regeneration can induce opposite hydrological changes. An observatory including long-term field measurements of fine-scale land-use mosaics and of hydrometeorological variables has been operating in several headwater catchments in tropical southeast Asia since 2000. The GR2M water balance model, repeatedly calibrated over successive 1-year periods and used in simulation mode with the same year of rainfall input, allowed the hydrological effect of land-use change to be isolated from that of rainfall variability in two of these catchments in Laos and Vietnam. Visual inspection of hydrographs, correlation analyses, and trend detection tests allowed causality between land-use changes and changes in seasonal streamflow to be ascertained. In Laos, the combination of shifting cultivation system (alternation of rice and fallow) and the gradual increase of teak tree plantations replacing fallow led to intricate streamflow patterns: pluri-annual streamflow cycles induced by the shifting system, on top of a gradual streamflow increase over years caused by the spread of the plantations. In Vietnam, the abandonment of continuously cropped areas combined with patches of mix-trees plantations led to the natural re-growth of forest communities followed by a gradual drop in streamflow. Soil infiltrability controlled by surface crusting is the predominant process explaining why two modes of afforestation (natural regeneration vs. planting) led to opposite changes in streamflow regime. Given that commercial tree plantations will continue to expand in the humid tropics, careful consideration is needed before attributing to them positive effects on water and soil conservation.en
dc.description.sponsorshipFrench watershed network SOERE-RBV (reseau des bassins versants); French Observatory for Sciences of Universe (Observatoire des Sciences de l'Univers); CGIAR research program on Integrated Systems for the Humid Tropics; French ANR TECITEASY [ANR-13-AGRO-0007]en
dc.language.isoenen
dc.publisherCOPERNICUS GESELLSCHAFT MBHen
dc.relation.urlhttp://www.hydrol-earth-syst-sci.net/20/2691/2016/en
dc.rights© Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License.en
dc.titleContradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modellingen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Grad Collen
dc.identifier.journalHydrology and Earth System Sciencesen
dc.description.noteOpen Access Journalen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
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