Effect of forest thinning on the radar backscattering coefficient at L-band

Champion, Isabelle; Guyon, Dominique; Riom, J.; Toan, Thuy Le; Beaudoin, A.

doi:10.1080/014311698214992

Cited by 12 publications

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“…We observed smaller changes in σ 0 than those observed by Champion et al (1998), who reported a decrease in σ 0 of 3 to 4 dB at a 25% level of thinning, similar to the thinning level in this study, in a maritime pine forest in France. The small change in σ 0 of less than 1 dB at our study site may be due to the presence of a lower canopy and understory vegetation.…”

Section: Polcontrasting

confidence: 50%

“…The small change in σ 0 of less than 1 dB at our study site may be due to the presence of a lower canopy and understory vegetation. Champion et al (1998) also reported that a numerical simulation predicted a smaller value (1 dB or less) than the value they observed and attributed the discrepancy between their observations and the numerical simulation results to the simple treatment of forest structure and a lack of consideration of a change in vegetation below the canopy in the numerical model.…”

Section: Polmentioning

confidence: 91%

“…The geometric properties of trees, such as tree architecture (Dobson et al, 1995), stand density (Watanabe et al, 2006), and gaps due to windthrow (trees uprooted or broken by wind) (Green, 1998), also influence σ 0 . However, few studies have examined the effects of intermediatemagnitude changes in a forest, such as those due to thinning, on σ 0 (e.g., Champion et al, 1998). Further research on such intermediate disturbances is needed to provide information for forest management, and it is also an urgent topic for detecting illegal tree cutting, especially in tropical forests.…”

Section: Introductionmentioning

confidence: 99%

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Influence of forest disturbances on backscatter of the airborne L-band synthetic-aperture radar in a larch forest in northern Japan

Takahashi

Oguma

Shimada

et al. 2011

Hydrological Research Letters

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Abstract:This paper is a case study on the detection of forest disturbances in airborne synthetic-aperture radar (SAR) data. We investigated changes in the L-band SAR backscattering coefficient (σ 0 ) following thinning and a typhoon in a larch forest in northern Japan. The thinning caused changes of intermediate magnitude in the above-ground biomass (AGB), whereas the typhoon broke or uprooted most of the trees, thereby significantly changing the forest structure without changing the biomass. Thinning led to backscattering coefficients change of less than about 1 dB; HV polarization was most sensitive to the change in AGB, and HH was insensitive to it. In the case of the typhoon, VV was sensitive to the change in forest structure, whereas HH and HV were insensitive to it, suggesting that the tree trunks, which were felled in one direction by the typhoon, enhanced the backscattering signal of the polarisation that accorded with the trunk direction.

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Section: Polcontrasting

confidence: 50%

Section: Polmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Influence of forest disturbances on backscatter of the airborne L-band synthetic-aperture radar in a larch forest in northern Japan

Takahashi

Oguma

Shimada

et al. 2011

Hydrological Research Letters

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“…In addition, the spectral reflectance of Amazonian forests is influenced by many factors-the vegetation's structure, the canopy moisture levels, the shadow effect, the complexity of the landscape, the local climatic conditions, and the soil moisture content (Castel et al, 2002;Champion et al, 1998;Imhoff, 1995;Iverson et al, 1994;Roy and Ravan, 1996;Sader, 1987;Santos et al, 2002). Due to these complexities, many uncertainties remain in utilizing remote sensing technologies for estimating the biomass in the Amazon Basin, especially in the accuracy of the spectrum-biomass models and its determinants.…”

Section: Remote Sensing Approachmentioning

confidence: 98%

A framework for creating and validating a non-linear spectrum-biomass model to estimate the secondary succession biomass in moist tropical forests

Mausel

Brondı́zio

et al. 2010

ISPRS Journal of Photogrammetry and Remote Sensing

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“…The knowledge of the interaction mechanisms between SAR (Synthetic Aperture Radar) signals and the structural properties of forests was investigated in the several studies ( VAN ZYL et al, 1987;KASISCHKE et al, 1997;CHAMPION et al, 1998;COOPS, 2002;NEEFF et al, 2005). Characteristics of forest coverage (e.g.…”

Section: Introductionmentioning

confidence: 99%

Análise dos parâmetros estruturais de tipologias florestais utilizando dados SAR em banda L

2010

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The main objective of this work is the investigation of the relationship between the polarimetric L-band backscatter (σº) from different incidence angles (collected by the airborne sensor R99-B/SIPAM) and the structural parameters of the primary and secondary forest typologies. The area under study is located at the Tapajós National Forest and surroundings (Pará State, Brazil). Using the Freeman-Durden target decomposition technique, the basic backscatter mechanisms are presented to verify the contributions of the physiognomic-structural components of these forest stands in the L-band signal responses. As a conclusion, it is possible to verify that the variable "tree height" has better relations with the backscatter values, when compared to other structural variables, especially when the model also includes variations of the incidence angle of the stripes imaged. The Freeman-Durden decomposition technique indicates that the volumetric scattering component has the strongest influence on the L-band at primary and secondary tropical forests at incidence angles between 52 and 70 degrees, mainly due to the high incidence angle and, consequently the low depth vertical penetration. Keywords: Forest Inventory; L-Band; SAR Data; Mapping; Tropical Forest; Amazon.Bol. Ciênc. Geod., sec. Artigos, Curitiba, v. 16, n o 3, p.475-489, jul-set, 2010.Analysis of structural parameters of forest typologies using ... 4 7 6 RESUMO O objetivo principal desse trabalho é investigar a relação entre o retroespalhamento (σ°) de dados SAR polarimétricos de banda L, em diferentes ângulos de incidência (coletado pelo sensor aerotransportado R99-B/SIPAM) e os parâmetros estruturais de sítios de floresta primária e sucessão secundária. A área selecionada para esse estudo está localizada na região da Floresta Nacional do Tapajós (Estado do Pará, Brasil) e áreas circunvizinhas. É utilizada a técnica de decomposição de alvos de Freeman-Durden na avaliação dos mecanismos básicos de espalhamento, para verificar a contribuições das componentes fisionômico-estruturais dos alvos florestais na resposta-radar de banda L. Como conclusão, é possível verificar que a variável "altura das árvores" teve melhor relação com os valores de retroespalhamento, quando comparado com outras variáveis biofísicas, especialmente quando o modelo também incluiu variações do ângulo de incidência na direção em range. A técnica de decomposição de Freeman-Durden indicou que a componente volumétrica de espalhamento tem uma forte influência na resposta em banda L para florestas tropicais primárias e secundárias,em ângulos de incidência entre 52 e 70 graus, devido principalmente ao elevado ângulo de incidência e, consequentemente a baixa profundidade de penetração vertical da onda incidente.

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Effect of forest thinning on the radar backscattering coefficient at L-band

Cited by 12 publications

References 0 publications

Influence of forest disturbances on backscatter of the airborne L-band synthetic-aperture radar in a larch forest in northern Japan

Influence of forest disturbances on backscatter of the airborne L-band synthetic-aperture radar in a larch forest in northern Japan

A framework for creating and validating a non-linear spectrum-biomass model to estimate the secondary succession biomass in moist tropical forests

Análise dos parâmetros estruturais de tipologias florestais utilizando dados SAR em banda L

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