 |
| Titel |
Post-fire soil erosion on vineyards and canary pine-stands on the subtropical island of La Palma: scope of application of TLS? |
| VerfasserIn |
Kathrin Umstaedter, Florian Haas, Michael Becht |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078373
|
|
|
|
|
|
| Zusammenfassung |
| Land use is considered as a main factor regarding post-fire soil erosion. Especially in the
subtropical climate with extreme rainfall events in winter and drought periods during
summer times, soil erosion can clearly exceed the soil reproduction rate. On the
Canary Island of La Palma frequent wildfires and steep slopes contribute to a high
likelihood of post-fire soil erosion. For a quantitative measurement of the erosion rate
a terrestrial Laser Scanner with high resolution in combination with a dGPS is
used.
The main target of this study is to quantify the post-fire soil erosion rates on study sites
with a different land use on the island of La Palma (Canary Islands). The investigation
focuses on two land use forms; both are very common and widespread on the island: canary
pine stands and vineyard areas. The study sites are characterized by a varying steepness, a
different fire history (wildfires in 2000, 2009 and 2012) and different stages of soil
development. Both denudation and gully erosion processes are spread over the sites. Intense
precipitation events can trigger debris flows and extensive soil erosion on post-fire sites, like
in the year 2009 in the south or in 2012 on the west and east side of La Palma. Regarding
that, erosion is not just a problem for agriculture, but for the infrastructure. For our project
we assume, that different topography, different land use and different forest fire
history can result in a different soil erosion rate and type (gully incision, denudation
processes).
To calculate the post-fire erosion rates of the two land use forms, 24 study sites – 10 sites
in vineyard areas, 14 in canary pines stands – were selected. By means of a 3D terrestrial
Laser Scanner (Riegl LMS Z420i), high resolution digital terrain models of the study sites
were compiled. The data acquisition was carried out in October 2011, May 2012 and
December 2012 and subsequently the terrain models were compared. With this method not
only erosion rates can be detected, but areas with erosion and areas with accumulation can be
identified. As additional information precipitation data of the measured time periods were
acquired.
For a better differentiation of the soil properties, soil profiles and soil samples of each
study site were analyzed. Supplementary the occurrence of considerable erosion forms shall
be detected by the comparison of aerial images of former years and analyzed in consideration
of possible fire events.
One target of our investigation shall be the answer of the question if the chosen methods
can model the erosion rate and the distribution of erosion and accumulation in a satisfactory
manner. |
|
|
|
|
|
|