Short‐rotation coppice (SRC) has great potential for supplying biomass‐based heat and energy, but little is known about SRC's ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar (Populus) SRC 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 (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow (F_s) 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 (∆D) was monitored simultaneously with F_s 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 ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆D (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 SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

中文翻译：

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多基因型杨树短轮换期小林从树到林分的用水量。


短旋转林地（SRC）在提供生物质热量和能源方面具有巨大潜力，但人们对 SRC 的生态足迹，特别是其对水循环的影响知之甚少。为此，我们对东佛兰德斯（比利时）商业规模的杨树 ( Populus ) SRC 人工林的树木和林分水平的用水量进行了量化，主要关注蒸腾成分。首先，我们使用 AquaCrop 模型和涡流协方差通量数据来分析整个生长季节的水平衡的不同组成部分。蒸腾量占全年林分尺度蒸散量 (ET) 的 59%。与参考草地的蒸散量相比，测量的蒸散量和模拟的蒸散量较低，这表明 SRC 仅使用了有限的水量。其次，我们在 2011 年夏末为期 39 天的密集田间活动期间，比较了单个植物的叶面积比例和边材面积比例的液流 ( F _s ) 测量值与林分比例涡流协方差通量数据。每日茎直径变化 (Δ D )与F _s同时监测，以了解三种杨树基因型的用水策略。基于边材面积或叶面积缩放的冠层蒸腾量分别为 43.5 和 50.3 毫米，分别占集约田间活动期间测得的生态系统总蒸散量的 74% 和 86%。除了生长差异外，每日 Δ D的显着基因型间差异（由于茎收缩和肿胀）表明三种基因型之间存在不同的用水策略，这已通过液流测量得到证实。 未来关于 SRC 用水预测或提高 SRC 基因型生物量产量的研究，应考虑树水平蒸腾水损失的基因型差异以及林分水平 SRC 水平衡。