Laser Remote Sensing of Vegetation

Kanevski, V. A.; Ross, Juhan; Kochubey, Svetlana M.; Shadchina, T. M.

doi:10.1007/978-3-642-57966-0_4

Cited by 4 publications

(2 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Development of quantitative assessment is required. Another laser ranging method (e.g., Kanevski et al 1994) measures the time or phase differences of laser beams to obtain two-dimensional sections of the three-dimensional structure of the forest canopy. Because this method does not measure strength of laser reflections, an ordinary passive radiometer system is required to be adapted to determine the spectral characteristics of the canopy (e.g., Yamashita et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Distinguishing foliage from branches in the non-destructive measurement of the three-dimensional structure of mountain forest canopies

Tanaka¹,

Hotaek²,

Hattori³

2003

The Forestry Chronicle

View full text Add to dashboard Cite

Mountainous forest canopies usually present a slanted, rough and porous surface. To clarify the effect of forest on radiative and convective exchanges, the three-dimensional structure of the canopy should be measured. An earlier study examined the laser plane rangefinding method as a new non-destructive way to measure it. In this study, to distinguish foliage from branches using the results of measurements, detected values of reflection were adjusted to compensate for varying distances from the detector to canopy elements. When the laser reflection values were adjusted by using the 1.5-th power of the distance, the calculations could distinguish foliage from stems.Key words: Mountainous forest, canopy, non-destructive, three-dimensional structure, laser, range-finding method, NDVI, CCD camera Les cimes des forêts montagneuses présentent habituellement une surface inclinée, rugueuse et poreuse. Afin de préciser l'effet des forêts sur les échanges de rayonnement et de convection, il faudrait mesurer la structure tri-dimensionnelle du couvert des arbres. Une étude antérieure avait examiné la méthode d'étude au moyen d'un plan défini par laser en tant que moyen non destructif de mesure du couvert. Au cours de cette étude, afin de distinguer le feuillage des branches au moyen des résultats des mesures, les valeurs de réflex-ion détectées ont été ajustées pour compenser pour les distances variables entre le détecteur et les éléments du couvert. Lorsque les valeurs de réflexion du laser ont été ajustées en utilisant une fois et demie la puissance de la distance, les calculs pourraient distinguer entre le feuillage et les tiges.

show abstract

Section: Discussionmentioning

confidence: 99%

Distinguishing foliage from branches in the non-destructive measurement of the three-dimensional structure of mountain forest canopies

Tanaka¹,

Hotaek²,

Hattori³

2003

The Forestry Chronicle

View full text Add to dashboard Cite

show abstract

“…In the future, if a lidar system is used that can receive the returned laser energy in a direction different from the incident beam direction, a hot spot interaction term as a function of incident and returned directions must be added to (1). The use of such bistatic lasers (although not lidars) to plant canopy analysis has been described by [11].…”

Section: Letmentioning

confidence: 99%

Modeling lidar waveforms in heterogeneous and discrete canopies

Ni‐Meister

Jupp

Dubayah

2001

IEEE Trans. Geosci. Remote Sensing

224

125

View full text Add to dashboard Cite

This study explores the relationship between laser waveforms and canopy structure parameters and the effects of the spatial arrangement of canopy structure on this relationship through a geometric optical model. Studying laser waveforms for such plant canopies is needed for the advanced retrieval of three-dimensional (3-D) canopy structure parameters from the vegetation canopy lidar (VCL) mission.For discontinuous plant canopies, a hybrid geometric optical and radiative transfer (GORT) model describing the effects of 3-D canopy structure parameters of discrete canopies on the radiation environment has been modified for use with lidar. The GORT model is first used to describe the canopy lidar waveforms as a function of canopy structure parameters and then validated using scanning lidar imager of canopies by echo recovery (SLICER) data collected in conifer forests in central Canada during the boreal ecosystem-atmosphere study (BOREAS).Model simulations show that the clumping in natural vegetation, such as leaves clustering into tree crowns causes larger gap probability and smaller waveforms for discontinuous plant canopies than for horizontally homogeneous plant canopies. Ignoring the clumping effect can result in significantly lower values for the estimated foliage amount in the profile and in turn lower estimated biomass. Because of clumping, only the gap probability and apparent vertical projected foliage profile can be directly retrieved from the canopy lidar data. The retrieval is sensitive to the ratio of the volume backscattering coefficients of the vegetation and background, and this ratio depends on canopy architecture as well as foliage spectral characteristics. Extensions of the GORT model from single-layered canopies to include multilayered ones are also explored. Index Terms-Geometric optical and radiative transfer (GORT) model, heterogeneous plant canopies, lidar waveforms. NOMENCLATURE Roman AlphabetVertical crown radius (m). Foliage area volume density of a single crown (m ). Apparent foliage profile as a function height (m ). Actual foliage profile as a function height (m ).

show abstract