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| Titel |
Long-term persistence of throughfall yield assessed by small footprint LiDAR
data |
| VerfasserIn |
Sebastian Bischoff, Delphis F. Levia, Jens Nieschulze, Florian Schulz, Beate Michalzik |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250133929
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| Publikation (Nr.) |
 EGU/EGU2016-14595.pdf |
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| Zusammenfassung |
| Throughfall (TF) represents an important relocation mechanism for the spatial distribution of
intercepted precipitation and hence associated nutrients in wooded ecosystems. To date, a
broad range of studies showed that the spatial patterns of TF distribution exhibit a
pronounced temporal stability. These studies, however, have examined TF temporal stability
at the tree scale or they were computed from event-based data. Here, we seek to evaluate
the utility of temporally aggregated TF data at one, three, and six year intervals to
determine whether such long-term TF monitoring data could serve as the basis for TF
temporal persistence measurements for both beech and spruce forests. In addition,
we examine the temporal persistence of TF in relation to small footprint LiDAR
data.
In context of the German Science Foundation (DFG) founded “Biodiversity
Exploratories” (www.biodiversity-exploratories.de) we studied water-bound nutrient fluxes
on a set of three differently managed forest plots (spruce plantation, age class forest beech,
unmanaged beech) in central Germany throughout the vegetation periods of 2010 – 2015. For
long-term monitoring purposes, TF samples were collected in biweekly routine
sampling intervals using X-shaped transects of 20 bulk samplers (axis length 32 m) per
experimental plot. In this study, we aim to identify canopy structural parameters explaining
the temporal patterns observed. We therefore used small footprint LiDAR (Light
Detection And Ranging) data to calculate several canopy structural parameters on base
of a gridded canopy model (grid cell resolution = 0.75 m). As LiDAR allows a
three-dimensional description of the complex forest canopy structure it might help
to extend our understanding of complex canopy processes influencing the spatial
dispersal of precipitation water, and hence associated nutrient fluxes, in wooded
ecosystems.
Preliminary data analysis reveals that normalized TF values identify a number of TF
collectors on each of the three study plots which show significantly lower or respectively
higher TF values throughout the whole study period. Time stability plots furthermore exhibit
pronounced differences between the two different tree species as well as between different
stand ages of beech. In particular, they exhibit a higher temporal variability under spruce as
well as a higher spatial variability of TF distribution for the younger even-aged
beech stand compared to the unmanaged one. Preliminary analysis further showed
that TF amount also is correlated to structural parameters like e.g. slope, aspect or
texture of the outer canopy surface and that different structural parameters might be
responsible depending on tree species or even growth structure. These preliminary
results suggest that long-term throughfall monitoring is useful in establishing the
spatiotemporal heterogeneity of TF inputs into both deciduous and coniferous forests. |
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