Indirect Estimation of Leaf Area Index in VSP-Trained Grapevines Using Plant Area Index

2013 ◽  
Vol 65 (1) ◽  
pp. 153-158 ◽  
Author(s):  
J. Doring ◽  
M. Stoll ◽  
R. Kauer ◽  
M. Frisch ◽  
S. Tittmann
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Area Index ◽  
Indirect Estimation ◽  
Plant Area Index ◽  
Plant Area

scholarly journals Estimation of Leaf Area Index and Plant Area Index of a Submerged Macrophyte Canopy Using Digital Photography

PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e51034 ◽  
Author(s):  
Dehua Zhao ◽  
Dong Xie ◽  
Hengjie Zhou ◽  
Hao Jiang ◽  
Shuqing An
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Digital Photography ◽  
Submerged Macrophyte ◽  
Area Index ◽  
Plant Area Index ◽  
Plant Area

scholarly journals Leaf area index mapping with optical methods and allometric models in SMEAR flux tower footprint at Järvselja, Estonia

2015 ◽  
Vol 63 (1) ◽  
pp. 85-99
Author(s):  
Marta Mõistus ◽  
Mait Lang
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Point Cloud ◽  
Forest Growth ◽  
Height Distribution ◽  
Area Index ◽  
Flux Tower ◽  
Gap Fraction ◽  
Plant Area Index ◽  
The Relationship

AbstractLeaf area index (LAI) characterizes the amount of photosynthetically active tissue in plant canopies. LAI is one of the key factors determining ecosystem net primary production and gas and energy exchange between the canopy and the atmosphere. The aim of the present study was to test different methods for LAI and effective plant area index (PAIe) estimation in mixed hemiboreal forests in Järvselja SMEAR Estonia (Station for Measuring Ecosystem-Atmosphere Relations) flux tower footprint. We used digital hemispherical images from sample plots, forest management inventory data, allometric foliage mass models, airborne discrete-return recording laser scanner (ALS) data and multispectral satellite images. The free ware program HemiSpherical Project Manager (HSP) was used to calculate canopy gap fraction from digital hemispherical photographs taken in 25 sample plots. PAIewas calculated from the gap fraction for up-scaling based on ALS point cloud metrics. The all ALS pulse returns-based canopy transmission was found to be the most suitable lidar metric to estimate PAIein Järvselja forests. The 95-percentile (H95) of lidar point cloud height distribution correlates very well with allometric regression models based LAI and in birch stands the relationship was fitted with 0.7 m2m−2residual error. However, the relationship was specific to each allometric foliage mass model and systematic discrepancies were detected at large LAI values between the models. Relationships between the spectral reflectance and allometric LAI were not good enough to be used for LAI mapping. Therefore, airborne laser scanning data-based PAIemap was created for areas near SMEAR tower. We recommend to establish a network of permanent sample plots for forest growth and gap fraction measurements into the flux footprint of SMEAR Estonia flux tower in Järvselja to provide consistent up to date data for interpretation of the flux measurements.

Comparison of direct and indirect estimation of leaf area index in mature Norway spruce stands of eastern Germany

2000 ◽  
Vol 30 (3) ◽  
pp. 440-447 ◽  
Author(s):  
Ralf Küßner ◽  
Reinhard Mosandl
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Norway Spruce ◽  
Stand Structure ◽  
Stand Density ◽  
Area Index ◽  
Model Calculations ◽  
Indirect Estimation ◽  
Eastern Germany ◽  
Spruce Stands

IIn three mature Norway spruce (Picea abies (L.) Karst.) stands of the Erzgebirge (Ore Mountains) in eastern Germany, the performance of the LAI-2000 plant canopy analyzer (LI-COR instruments) was tested for indirect estimation of leaf area index (LAI). The LAI-2000 calculates effective leaf area index (LAIe, m2/m2) resulting from radiation measurements and subsequent model calculations. LAIe underestimated directly estimated half the total leaf area index (LAI0.5t, m2/m2) by 37-82% as determined from allometric relationships derived from subsample harvesting. The degree of underestimation was dependent upon stand density in two of three spruce stands examined; it was the highest in sparsely stocked plots. The relationship of LAIe to allometrically determined LAI0.5t for one of the three stands differed significantly from the other two spruce stands and the underestimation of LAI0.5t was less distinct. This was explained by stand structure, i.e., higher amounts of nonassimilating surfaces relative to LAI0.5t. These results indicate that the LAI-2000 is not generally applicable for estimation of LAI in mature spruce stands of the Erzgebirge because of effects of stand structure on LAIe-LAI0.5t relationships, which are stand specific.

scholarly journals Photographic assessment of overstory and understory leaf area index in beech forests under different management regimes in Central Italy

2014 ◽  
Vol 61 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Francesco Chianucci ◽  
Nicola Puletti ◽  
Ernesto Venturi ◽  
Andrea Cutini ◽  
Ugo Chiavetta
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Large Scale ◽  
Central Italy ◽  
Canopy Cover ◽  
Significant Negative Correlation ◽  
Forest Understory ◽  
Area Index ◽  
Management Regime ◽  
Plant Area Index

Abstract. Forest understory may be strongly affected by silvicultural practices such as thinning, which simultaneously modulates the overstory canopy cover and influences the availability of light. However, the understory layer is rarely considered in management decisions, partly because methods to estimate understory leaf area index are poorly developed. In this study we used two different restricted view angle photographic methods to estimate overstory plant area index LO (zenith cover photography), understory leaf area index LU (nadir cover photography) and their related canopy attributes (foliage clumping, foliage cover, crown cover, crown porosity). These measurements were performed in beech stands under different management regime. Results from photography indicated that not only overstory but also understory canopy attributes were significantly influenced by forest management. In addition, a significant negative correlation was found between LO and LU. We conclude that the photographic methods are effective for monitoring (overstory and understory) canopy status in managed stands, on account of their rapid and not destructive procedures, which allows large scale implementation of the methods.

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