Interception in a mountainous declining spruce stand in the Strengbach catchment (Vosges, France)
ABSTRACT In a over-mature (declining) 90-year-old Norway spruce stand (Picea abies) in the Vosges mountain area, gross precipitation, throughfall, stemflow and meteorological variables have been measured for three periods in the summers of 1988, 1989 and 1990; transpiration was measured from June to August 1989. Throughfall, interception and stemflow represent, respectively, 65.3%, 34.2% and 0.5% of the incident rainfall. A semi-logarithmic relationship between interception and gross precipitation is given. Transpiration of the stand determined by sap-flow measurements represents only 27% of the potential evapotranspiration. Evaporation of water intercepted by the vegetation is the major component of the evapotranspiration.
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ABSTRACT: A wide range of basic and applied problems in water resources research requires high-quality estimates of the spatial mean of throughfall. Many throughfall sampling schemes, however, are not optimally adapted to the system under study. The application of inappropriate sampling schemes may partly reflect the lack of generally applicable guidelines on throughfall sampling strategies. In this study we conducted virtual sampling experiments using simulated fields which are based on empirical throughfall data from three structurally distinct forests (a 12-yr old teak plantation, a 5-yr old young secondary forest, and a 130-yr old secondary forest). In the virtual sampling experiments we assessed the relative error of mean throughfall estimates for 38 different throughfall sampling schemes comprising a variety of funnel- and trough-type collectors and a large range of sample sizes. Moreover, we tested the performance of each scheme for both event-based and accumulated throughfall data. The key findings of our study are threefold. First, as errors of mean throughfall estimates vary as a function of throughfall depth, the decision on which temporal scale (i.e. event-based versus accumulated data) to sample strongly influences the required sampling effort. Second, given a chosen temporal scale throughfall estimates can vary considerably as a function of canopy complexity. Accordingly, throughfall sampling in simply structured forests requires a comparatively modest effort, whereas heterogeneous forests can be extreme in terms of sampling requirements, particularly if the focus is on reliable data of small events. Third, the efficiency of trough-type collectors depends on the spatial structure of throughfall. Strong, long-ranging throughfall patterns decrease the efficiency of troughs substantially. Based on the results of our virtual sampling experiments, which we evaluated by applying two contrasting sampling approaches simultaneously, we derive readily applicable guidelines for throughfall monitoring.Agricultural and Forest Meteorology 06/2014; 189-190:125-139. · 3.89 Impact Factor
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ABSTRACT: The Loess Plateau of China has long been suffering from severe soil erosion due to deforestation and other human being-related activities. Reforestation has been regarded as an important measure to protect and recover degraded ecosystems. The two typical forest stands, the secondary natural succession Populus davidiana stand (PDS) and the plantation Pinus tabulaeformis stand (PTS), were chosen to analyse their effectiveness in conserving soil and water and understand their impacts on rainfall distribution. On the basis of observations in 1988–2000 (no available data in 1989), compared with croplands, PDS and PTS reduced soil loss by 99·9% and reduced runoff by 92·3% and 84·4%, respectively. The mean annual canopy interception was 14·0% for PDS and 25·3% for PTS, and litter interception was 7·7% for PDS and 11·6% for PTS in 1995–2000. Both forest stands had almost the same stemflow percentage of 3·3%. However, there was no significant difference in runoff and soil loss between the two reforestation types. These results suggest that both the plantation PTS and the natural regeneration PDS are effective in controlling soil erosion, with similar potentials in conserving soil and water in the study region. Copyright © 2013 John Wiley & Sons, Ltd.Ecohydrology 04/2013; · 2.78 Impact Factor