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Spatial distribution of water use by eucalyptus plantations in a small catchment in Guangxi, South China : a modelling and GIS approach

Show simple item record 2009-10-05T10:20:25Z 2015-07-23T10:43:28Z 2009-10-05T10:20:25Z 2015-07-23T10:43:28Z 2009-05
dc.title Spatial distribution of water use by eucalyptus plantations in a small catchment in Guangxi, South China : a modelling and GIS approach en
ethesis.discipline Skogsresursvetenskap och -teknologi (skogsekologi / geoinformatik) sv
ethesis.discipline Forest Resource Science and Technology (Forest ecology / Geoinformatics) en
ethesis.discipline Metsävaratiede ja -teknologia (metsäekologia / geoinformatiikka) fi
ethesis.department Institutionen för skogstillgångar sv
ethesis.department Institutionen för skogsvetenskaper sv
ethesis.department Department of Forest Resource Management en
ethesis.department Department of Forest Sciences en
ethesis.department Metsävarojen käytön laitos fi
ethesis.department Metsätieteiden laitos fi
ethesis.faculty Agrikultur- och forstvetenskapliga fakulteten sv
ethesis.faculty Faculty of Agriculture and Forestry en
ethesis.faculty Maatalous-metsätieteellinen tiedekunta fi
ethesis.faculty.URI Helsingfors universitet sv University of Helsinki en Helsingin yliopisto fi
dct.creator Yan, Dongjun
dct.issued 2009
dct.language.ISO639-2 eng
dct.abstract Industrial plantations of eucalyptus are sharply increasing in Asia. Although supplying raw material for the pulp and paper industry, easing deforestation on native forests and increasing carbon sequestration to help counter global warming, there are several concerns about the environmental effects of industrial eucalyptus plantations. These concerns include invasiveness of eucalyptus and loss of biodiversity, loss of land for food production, loss of soil fertility due to short rotation times and biomass removal, and excessive water-use and reduced catchment water yields. With protagonists on both sides, there is a need to research and examine the environmental effects of industrial eucalyptus plantations in southern China. We modelled and mapped the spatial distribution of water balance components across a small (752 ha) catchment in Guangxi province in relation to land-use, including industrial and local community plantations of eucalyptus and agriculture. Studies about the spatial distribution of water-use by eucalyptus across the landscape are few. WATBAL, a water balance model with a monthly time step, was parameterized and used to derive water balance components for 180 selected locations in the catchment. From the model output, continuous (predictive) surfaces for monthly (long-term average) potential (PET) and actual evapotranspiration (AET), evapotranspiration deficit (PET- AET), surface runoff and drainage below rooting zone were generated using GIS (ArcGIS 9.2). Averaged across the catchment, annual (October- September) actual evapotranspiration accounted for 77 %, surface runoff for 15 % and drainage below rooting zone for 8 % of rainfall. Differences between land-use types were relatively small, but areas of highest actual evapotranspiration and lowest surface runoff were associated with the oldest (6-7 years old) forested areas, including pure and mixed eucalyptus industrial plantations and local community, coppiced plantations on the slopes. The areas with the lowest actual evapotranspiration were associated with agricultural crops in the bottom of the catchment. The clear dominance of actual evapotranspiration in the water balance of all land-use types reflects the dominating role of the evaporative potential of the climate, with land-use cover, soil and topography factors playing secondary roles. While water-use was the highest for the forested areas, eucalyptus per se did not use more water than mixed plantations or those of the local community. Tree cover in general reduced surface runoff and therefore would reduce the risk of erosion. Using our modelling and mapping approach, we were able to assess the water-use and other components of the water balance of eucalyptus plantations and other land use types for this catchment. The study showed the importance of having suitable and adequate ground truth data in order to derive reliable and useful interpolation surfaces using ArcGIS. en
dct.subject water balance en
dct.subject WATBAL en
dct.subject hydrology en
dct.subject GIS en
dct.subject Eucalyptus en
dct.subject spatial distribution en
dct.subject South China en
dct.subject GIS en
dct.subject forest ecology en
dct.language en
ethesis.language English en
ethesis.language englanti fi
ethesis.language engelska sv
ethesis.thesistype pro gradu-avhandlingar sv
ethesis.thesistype pro gradu -tutkielmat fi
ethesis.thesistype master's thesis en
dct.identifier.urn URN:NBN:fi:hulib-201507211631
dc.type.dcmitype Text
dc.identifier.laitoskoodi 874

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