Indirect Measurement of Forest Leaf Area Index Using Path Length Distribution Model and Multispectral Canopy Imager

The performance of the LI-COR LAI-2000 Plant Canopy Analyzer (PCA) for indirect measurement of leaf area index (LAI) was evaluated in vineyards of California's North Coast region. Twelve plots were established, representing vineyards of differing trellis, cultivar, and planting density. Mean LAI ranged from 0.5- to 2.25-m2 leaf area per m2 ground area by direct measurement (defoliation). Indirect LAI derived by a standard two-azimuth, diagonal-transect measurement protocol was significantly related to direct LAI (r2 = 0.78, P ≤ 0.001). However, the PCA underestimated direct LAI by about a factor of two. Narrowing the instrument's conical field of view from 148° to 56° increased indirect LAI by 13% to 60% in vertically trained plots, but still resulted in substantial underestimation of direct values. Use of this PCA protocol in vineyards should therefore be accompanied by direct measurement for calibration purposes.

Download Full-text

Estimating the leaf area of an individual tree in urban areas using terrestrial laser scanner and path length distribution model

ISPRS Journal of Photogrammetry and Remote Sensing ◽

10.1016/j.isprsjprs.2018.07.015 ◽

2018 ◽

Vol 144 ◽

pp. 357-368 ◽

Cited By ~ 8

Author(s):

Ronghai Hu ◽

Elena Bournez ◽

Shiyu Cheng ◽

Hailan Jiang ◽

Françoise Nerry ◽

...

Keyword(s):

Leaf Area ◽

Urban Areas ◽

Path Length ◽

Laser Scanner ◽

Length Distribution ◽

Distribution Model ◽

Terrestrial Laser Scanner ◽

Individual Tree

Download Full-text

Comparison of LiDAR-based Models for True Leaf Area Index and Effective Leaf Area Index Estimation in Young Beech Forests

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun202068030559 ◽

2020 ◽

Vol 68 (3) ◽

pp. 559-566

Author(s):

Zdeněk Patočka ◽

Kateřina Novosadová ◽

Pavel Haninec ◽

Radek Pokorný ◽

Tomáš Mikita ◽

...

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Regression Models ◽

Canopy Structure ◽

Optical Methods ◽

Distribution Model ◽

Area Index ◽

Index Estimation ◽

Effective Leaf Area Index

The leaf area index (LAI) is one of the most common leaf area and canopy structure quantifiers. Direct LAI measurement and determination of canopy characteristics in larger areas is unrealistic due to the large number of measurements required to create the distribution model. This study compares the regression models for the ALS-based calculation of LAI, where the effective leaf area index (eLAI) determined by optical methods and the LAI determined by the direct destructive method and developed by allometric equations were used as response variables. LiDAR metrics and the laser penetration index (LPI) were used as predictor variables. The regression models of LPI and eLAI dependency and the LiDAR metrics and eLAI dependency showed coefficients of determination (R2) of 0.75 and 0.92, respectively; the advantage of using LiDAR metrics for more accurate modelling is demonstrated. The model for true LAI estimation reached a R2 of 0.88.

Download Full-text