scholarly journals Estimation of leaf area index based on spectral reflectance and its application to the evaluation of the spatial distribution of a kudzu-dominated community

2021 ◽  
Vol 66 (3) ◽  
pp. 133-140
Author(s):  
Hiroki Iwamoto ◽  
Osamu Watanabe
Keyword(s):  
Spatial Distribution ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Spectral Reflectance ◽  
Area Index

scholarly journals Spatial Distribution of Tree Species Governs the Spatio-Temporal Interaction of Leaf Area Index and Soil Moisture across a Forested Landscape

PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e58704 ◽  
Author(s):  
Kusum J. Naithani ◽  
Doug C. Baldwin ◽  
Katie P. Gaines ◽  
Henry Lin ◽  
David M. Eissenstat
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Tree Species ◽  
Area Index ◽  
Spatio Temporal ◽  
Temporal Interaction

scholarly journals A Spatial Relationship between Canopy and Understory Leaf Area Index in an Old-Growth Cool-Temperate Deciduous Forest

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1037
Author(s):  
Yosuke Tanioka ◽  
Yihan Cai ◽  
Hideyuki Ida ◽  
Mitsuru Hirota
Keyword(s):  
Spatial Distribution ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Deciduous Forest ◽  
Multiple Point ◽  
Spatial And Temporal Variability ◽  
Temperate Deciduous Forest ◽  
Area Index ◽  
Cool Temperate ◽  
Temperate Deciduous

Quantification of leaf area index (LAI) is essential for understanding forest productivity and the atmosphere–vegetation interface, where the majority of gas and energy exchange occurs. LAI is one of the most difficult plant variables to adequately quantify, owing to large spatial and temporal variability, and few studies have examined the horizontal and vertical distribution of LAI in forest ecosystems. In this study, we demonstrated the LAI distribution in each layer from the understory to canopy using multiple-point measurements (121 points) and examined the relationships among layers in a cool-temperate deciduous forest. LAI at each point, and the spatial distribution of LAI in each layer, varied within the forest. The spatial distribution of LAI in the upper layer was more heterogeneous than that of LAI at the scale of the entire forest. Significant negative correlations were observed between the upper- and lower-layer LAI. Our results indicate that the understory compensates for gaps in LAI in the upper layer; thus, the LAI of the entire forest tends to remain spatially homogeneous even in a mature forest ecosystem.

Estimating Absorbed Photosynthetic Radiation and Leaf Area Index from Spectral Reflectance in Wheat 1

1984 ◽  
Vol 76 (2) ◽  
pp. 300-306 ◽  
Author(s):  
G. Asrar ◽  
M. Fuchs ◽  
E. T. Kanemasu ◽  
J. L. Hatfield
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Spectral Reflectance ◽  
Area Index

scholarly journals Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

2006 ◽  
Vol 131 (3) ◽  
pp. 313-319 ◽  
Author(s):  
Libertad Mascarini ◽  
Gabriel A. Lorenzo ◽  
Fernando Vilella
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Spectral Reflectance ◽  
Limiting Factor ◽  
Simple Method ◽  
Area Index ◽  
Water Index ◽  
Significant Difference ◽  
Shoot System

In roses (Rosa ×hybrida L.), the bending of branches is a technique that modifies the canopy of the plant and could affect such parameters as the leaf area index (LAI), the quality of reflected light, and the water index (WI) of the plant. The measurement of spectral reflectance with remote sensors is a nondestructive, quick, and simple method to study these parameters. The aim of this paper is to quantify the modification of reflected radiation quality, the LAI and the water index of the plant with different canopies, and its impact on flowering and the number and quality of flowers produced. In R. ×hybrida `Terracotta', using the spectral crop reflectance, the red: far red ratio [red (R) = 680 nm; far red (FR) = 730 nm], percentage of blue light of reflected radiation, and vegetation indices [normalized difference vegetation index (NDVI), simple ratio index (SRI), water index (WI)] were calculated in two architectural managements: traditional (upright hedge) and bent shoot. NDVI had a greater correlation with LAI than SRI (r2 = 0.98 and 0.85, respectively), but SRI was more reliable for LAI values of 1 to 3.5. The bent shoot system compared to the traditional one decreased the R:FR ratio of reflected radiation and increased LAI and plant water content. These changes were related to a higher commercial quality of the flowers (longer flowering shoots with a larger stem diameter and fresh weight), although there was no significant difference in the number of flowers harvested. The period that showed the largest difference in the quality of the flower using the bent shoot system had a LAI of 2.8 vs. 1.8 with traditional management and a marked reduction in the R:FR of the light reflected by bent plants. The bent shoot system advanced the peak production by 1 month at the end of winter and improved the flowers at a time when sun radiation is limiting factor for production.

scholarly journals Estimating Leaf Area Index with a New Vegetation Index Considering the Influence of Rice Panicles

2019 ◽  
Vol 11 (15) ◽  
pp. 1809 ◽  
Author(s):  
He ◽  
Zhang ◽  
Su ◽  
Lu ◽  
Yao ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Spectral Reflectance ◽  
Vegetation Index ◽  
Near Infrared ◽  
Visible Region ◽  
Canopy Reflectance ◽  
Area Index ◽  
Red Edge ◽  
Rice Panicles

The emergence of rice panicle substantially changes the spectral reflectance of rice canopy and, as a result, decreases the accuracy of leaf area index (LAI) that was derived from vegetation indices (VIs). From a four-year field experiment with using rice varieties, nitrogen (N) rates, and planting densities, the spectral reflectance characteristics of panicles and the changes in canopy reflectance after panicle removal were investigated. A rice “panicle line”—graphical relationship between red-edge and near-infrared bands was constructed by using the near-infrared and red-edge spectral reflectance of rice panicles. Subsequently, a panicle-adjusted renormalized difference vegetation index (PRDVI) that was based on the “panicle line” and the renormalized difference vegetation index (RDVI) was developed to reduce the effects of rice panicles and background. The results showed that the effects of rice panicles on canopy reflectance were concentrated in the visible region and the near-infrared region. The red band (670 nm) was the most affected by panicles, while the red-edge bands (720–740 nm) were less affected. In addition, a combination of near-infrared and red-edge bands was for the one that best predicted LAI, and the difference vegetation index (DI) (976, 733) performed the best, although it had relatively low estimation accuracy (R2 = 0.60, RMSE = 1.41 m2/m2). From these findings, correcting the near-infrared band in the RDVI by the panicle adjustment factor (θ) developed the PRDVI, which was obtained while using the “panicle line”, and the less-affected red-edge band replaced the red band. Verification data from an unmanned aerial vehicle (UAV) showed that the PRDVI could minimize the panicle and background influence and was more sensitive to LAI (R2 = 0.77; RMSE = 1.01 m2/m2) than other VIs during the post-heading stage. Moreover, of all the assessed VIs, the PRDVI yielded the highest R2 (0.71) over the entire growth period, with an RMSE of 1.31 (m2/m2). These results suggest that the PRDVI is an efficient and suitable LAI estimation index.

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