In the wildfire community fuel moisture content (FMC) is the quantity of choice when
it comes to assess vegetation water status in relation to fire risk and fire behaviour. Field
measurements of FMC are both expensive and time consuming and, in addition, sampling
is often spatially inadequate. Remote sensing could represent an almost ideal solution
both in terms of spatial and temporal coverage, if a consistent relationship between FMC
and spectral reflectance could be established. A review of the literature suggests that it is
difficult to retrieve FMC for dense forest canopies with remote sensing platforms. This
study took a step back and explored the relationship between spectral reflectance and
vegetation water content at the leaf level, where several confounding factors present at
the canopy level are eliminated or controlled for. It also considered a conifer species,
because relatively little research has been produced on this topic for this type of
vegetation. The main goal was to establish if FMC can be derived directly from spectral
reflectance in the solar spectrum using two well known approaches, such as spectral
indices and continuum removal. It is also aimed at exploring if an alternative, indirect
way to measure FMC as ratio of Equivalent Water Thickness (EWT) and Specific Leaf
Weight (SLW) is feasible and accurate. The results derived from Douglas-fir
(Pseudotsuga menziesii (Mirb) Franco) needles used in this study suggested that FMC
was not directly retrievable from spectral reflectance but vegetation water content could
be assessed with sufficient accuracy in terms of EWT. Also the retrieval of SLW from
reflectance of fresh foliage proved to be challenging. Finally, the study also highlighted
several aspects in the relationships among foliar water content, dry matter content and
reflectance that require additional research. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/3369 |
| Date | 09 June 2011 |
| Creators | Visintini, Fabio |
| Contributors | Niemann, K. O. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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