Foliar Moisture Content from the Spectral Signature for Wildfire Risk Assessments in Valparaíso-Chile

Abstract

Fuel moisture content (FMC) proved to be one of the most relevant parameters for controlling fire behavior and risk, particularly at the wildland-urban interface (WUI). Data relating FMC to spectral indexes for different species are an important requirement identified by the wildfire safety community. In Valparaíso, the WUI is mainly composed of Eucalyptus Globulus and Pinus Radiata—commonly found in Mediterranean WUI areas—which represent the 97.51% of the forests plantation inventory. In this work we study the spectral signature of these species under different levels of FMC. In particular, we analyze the behavior of the spectral reflectance per each species at five dehydration stages, obtaining eighteen spectral indexes related to water content and, for Eucalyptus Globulus, the area of each leave—associated with the water content—is also computed. As the main outcome of this research, we provide a validated linear regression model associated with each spectral index and the fuel moisture content and moisture loss, per each species studied.

Analyzing the Capabilities of Electric Field Energy Harvesting Using Natural Leaves

“…The dimensions of the harvesting plate were established by optimizing the electrode surface based on the length of Magnolia Obavata leaves (smaller area species) and the breadth of Agapanthus Africanus leaves (smaller width species). Each bioelectrode was kept in a plastic bag to preserve the freshness and quality of leaves over time, as recommended in [36].…”

Retrieval of Vegetation Indices Related to Leaf Water Content from a Single Index: A Case Study of Eucalyptus globulus (Labill.) and Pinus radiata (D. Don.)

“…After the drying process, the spectrum and mass were measured. This dehydration was repeated a total of three times, following the guidelines presented in [ 9 , 10 ]. Finally, to obtain the completely dry leaf mass, a 24-h drying process was carried out.…”

“…Several researches have developed spectral indices with a high correlation with the moisture content. In this regard, we selected 18 vegetation indices previously reviewed in [ 9 ]. The complete list of indices is shown in Table 2 .…”

“…In our previous work [ 9 ], we studied the correlation of several vegetation indices with the water content in the leaves of Eucalyptus globulus and Pinus radiata . Given the coefficient of determination values, we hypothesized that it is possible to estimate some spectral indices using only the most suitable one used to recover the moisture content.…”

Drivers of Flammability of Eucalyptus globulus Labill Leaves: Terpenes, Essential Oils, and Moisture Content

“…In contrast to native forests, Eucalyptus plantations can substantially decrease water supplies because of the high demands for their growth [10][11][12]. These changes have led to a loss of biodiversity in Chile's native forests, homogenization of the landscape, and the fragmentation of native forests, increasing the vulnerability of the land to fire in both rural and urban forest areas [13][14][15][16][17].…”