Published in:
GCB Bioenergy, 9 (2017) 2, Seite 370-384
Language:
English
DOI:
10.1111/gcbb.12345
ISSN:
1757-1693;
1757-1707
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title><jats:p>Short‐rotation coppice (<jats:styled-content style="fixed-case">SRC</jats:styled-content>) has great potential for supplying biomass‐based heat and energy, but little is known about <jats:styled-content style="fixed-case">SRC</jats:styled-content>'s ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar (<jats:italic>Populus</jats:italic>) <jats:styled-content style="fixed-case">SRC</jats:styled-content> plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand‐level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (<jats:styled-content style="fixed-case">ET</jats:styled-content>) at stand scale over the whole year. Measured <jats:styled-content style="fixed-case">ET</jats:styled-content> and modelled <jats:styled-content style="fixed-case">ET</jats:styled-content> were lower as compared to the <jats:styled-content style="fixed-case">ET</jats:styled-content> of reference grassland, suggesting that the <jats:styled-content style="fixed-case">SRC</jats:styled-content> only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow (<jats:italic>F</jats:italic><jats:sub>s</jats:sub>) measurements on individual plants vs. stand scale eddy covariance flux data during a 39‐day intensive field campaign in late summer 2011. Daily stem diameter variation (∆<jats:italic>D</jats:italic>) was monitored simultaneously with <jats:italic>F</jats:italic><jats:sub>s</jats:sub> to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem <jats:styled-content style="fixed-case">ET</jats:styled-content> measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆<jats:italic>D</jats:italic> (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of <jats:styled-content style="fixed-case">SRC</jats:styled-content> water use, or efforts to enhance the biomass yield of <jats:styled-content style="fixed-case">SRC</jats:styled-content> genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the <jats:styled-content style="fixed-case">SRC</jats:styled-content> water balance at stand level.</jats:p>