Relationship between Light Use Efficiency and Photochemical Reflectance Index Corrected Using a BRDF Model at a Subtropical Mixed Forest

Light use efficiency (LUE) is a key indicator of vegetation photosynthesis, which provides important insights into how vegetation productivity responds to environmental conditions. The photochemical reflectance index (PRI) is based on reflectance at 531 and 570 nm, which reflects the xanthophyll cycle process of plants under different radiation conditions, and makes LUE related to plant optical characteristics. In this study, tower-based PRI and eddy covariance (EC) based LUEs were used to explore the ability of PRI to track LUE variations in a subtropical, evergreen mixed forest in South China. The results indicate that there is a stronger relationship between PRI and LUE, corrected by the bidirectional reflectance distribution function (BRDF), where R2 = 0.46 before correction and R2 = 0.60 after correction. Generally, PRI is able to capture diurnal and seasonal changes in LUE. Simultaneously, this study highlights a significant correlation between LUE and PRI, but there is also a large seasonal difference in its correlation. The correlation in winter was significantly stronger than summer. The strongest correlation is found in November (R2 = 0.91) and the weakest is in July (R2 = 0.34). Photosynthetically active radiation (PAR) had a strong influence on the LUE-PRI relationship, while vapor pressure deficit (VPD) and air temperature (Ta) had negative influences on the relationship between LUE and PRI. Terrestrial laser scanning is used to retrieve the vertical structure of forest crown. Our results show that the vegetation canopy structure (i.e., effective leaf area index, LAIe), extracted from terrestrial laser scanning (TLS) point data in subtropical mixed forests, had a weak influence on LUE. Our research suggests that environmental factors and vegetation canopy structures should be considered when using PRI to accurately estimate LUE.

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Airborne and Terrestrial Laser Scanning for Measuring Vegetation Canopy Structure

Laser Scanning for the Environmental Sciences ◽

10.1002/9781444311952.ch13 ◽

2009 ◽

pp. 201-219 ◽

Cited By ~ 7

Author(s):

F. M. Danson ◽

F. Morsdorf ◽

B. Koetz

Keyword(s):

Laser Scanning ◽

Canopy Structure ◽

Terrestrial Laser Scanning ◽

Vegetation Canopy

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Contrasting Development of Canopy Structure and Primary Production in Planted and Naturally Regenerated Red Pine Forests

Forests ◽

10.3390/f10070566 ◽

2019 ◽

Vol 10 (7) ◽

pp. 566 ◽

Cited By ~ 2

Author(s):

Laura J. Hickey ◽

Jeff Atkins ◽

Robert T. Fahey ◽

Mark T. Kreider ◽

Shea B. Wales ◽

...

Keyword(s):

Primary Production ◽

Canopy Structure ◽

Structural Complexity ◽

Red Pine ◽

Stem Density ◽

Light Use Efficiency ◽

Planted Forests ◽

Area Index ◽

Use Efficiency ◽

Naturally Regenerated Stands

Globally, planted forests are rapidly replacing naturally regenerated stands but the implications for canopy structure, carbon (C) storage, and the linkages between the two are unclear. We investigated the successional dynamics, interlinkages and mechanistic relationships between wood net primary production (NPPw) and canopy structure in planted and naturally regenerated red pine (Pinus resinosa Sol. ex Aiton) stands spanning ≥ 45 years of development. We focused our canopy structural analysis on leaf area index (LAI) and a spatially integrative, terrestrial LiDAR-based complexity measure, canopy rugosity, which is positively correlated with NPPw in several naturally regenerated forests, but which has not been investigated in planted stands. We estimated stand NPPw using a dendrochronological approach and examined whether canopy rugosity relates to light absorption and light–use efficiency. We found that canopy rugosity increased similarly with age in planted and naturally regenerated stands, despite differences in other structural features including LAI and stem density. However, the relationship between canopy rugosity and NPPw was negative in planted and not significant in naturally regenerated stands, indicating structural complexity is not a globally positive driver of NPPw. Underlying the negative NPPw-canopy rugosity relationship in planted stands was a corresponding decline in light-use efficiency, which peaked in the youngest, densely stocked stand with high LAI and low structural complexity. Even with significant differences in the developmental trajectories of canopy structure, NPPw, and light use, planted and naturally regenerated stands stored similar amounts of C in wood over a 45-year period. We conclude that widespread increases in planted forests are likely to affect age-related patterns in canopy structure and NPPw, but planted and naturally regenerated forests may function as comparable long-term C sinks via different structural and mechanistic pathways.

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Efisiensi Penggunaan Cahaya Matahari oleh Tebu pada Berbagai Tingkat Pemupukan Nitrogen dan Fosfor

Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy) ◽

10.24831/jai.v40i3.6828 ◽

1970 ◽

Vol 40 (3) ◽

Author(s):

Wawan Pembengo ◽

, Handoko ◽

, Suwarto

Keyword(s):

Dry Matter ◽

Phosphorus Deficiency ◽

Block Design ◽

Canopy Structure ◽

Leaf Nitrogen ◽

Light Use Efficiency ◽

Nitrogen And Phosphorus ◽

Area Index ◽

P Fertilizer ◽

Use Efficiency

Light use efficiency is a crucial parameter in plant growth associated with accumulation of energy interception. Nitrogen and phosphorus deficiency reduce leaf area index (LAI) and specific leaf nitrogen and phosphorus (SLN and SLP) content and reduce efficiency of light intercepted by plant canopy structure. This research was conducted in Kebun Bunga Mayang PTPN VII, North Lampung Regency, Lampung Province (04050’S, 104052’E, 38 m above sea level) from July 2008 to September 2009. Treatments were distributed in the field under a randomized complete block design factorial with three replications. The increase in nitrogen fertilizer (N) improved sugarcane light use efficiency. The light use efficiency of the sugarcane plants fertilized with 225 kg N ha-1 was 2.29 g MJ-1 at maximum stem phase. On the contrary, the increasing of phosphor (P) fertilizer did not affect light use efficiency but increased stem dry matter at maximum seedling phase or about 3 month after planting (3 MAP), at maximum stem phase (9 MAP), and at harvest (11 MAP); total dry matter at seedling phase (5 MAP) and at maximum stem phase (9 MAP). Nitrogen did not interact with P in affecting light use efficiency. Keywords: fertilization N and P, interception radiation, light use efficiency, sugarcane

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Derivation, Validation, and Sensitivity Analysis of Terrestrial Laser Scanning-Based Leaf Area Index

Canadian Journal of Remote Sensing ◽

10.1080/07038992.2016.1220829 ◽

2016 ◽

Vol 42 (6) ◽

pp. 719-729 ◽

Cited By ~ 12

Author(s):

Yumei Li ◽

Qinghua Guo ◽

Shengli Tao ◽

Guang Zheng ◽

Kaiguang Zhao ◽

...

Keyword(s):

Sensitivity Analysis ◽

Leaf Area Index ◽

Leaf Area ◽

Laser Scanning ◽

Terrestrial Laser Scanning ◽

Area Index

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Study of Subtropical Forestry Index Retrieval Using Terrestrial Laser Scanning and Hemispherical Photography

Mathematical Problems in Engineering ◽

10.1155/2015/206108 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 3

Author(s):

Ting Yun ◽

Weizheng Li ◽

Yuan Sun ◽

Lianfeng Xue

Keyword(s):

Laser Scanning ◽

Estimation Method ◽

Terrestrial Laser Scanning ◽

Tangent Plane ◽

Transfer Model ◽

Normal Vector ◽

Plant Canopy ◽

Hemispherical Photography ◽

Area Index ◽

Cloud Data

In order to retrieve gap fraction, leaf inclination angle, and leaf area index (LAI) of subtropical forestry canopy, here we acquired forestry detailed information by means of hemispherical photography, terrestrial laser scanning, and LAI-2200 plant canopy analyzer. Meanwhile, we presented a series of image processing and computer graphics algorithms that include image and point cloud data (PCD) segmentation methods for branch and leaf classification and PCD features, such as normal vector, tangent plane extraction, and hemispherical projection method for PCD coordinate transformation. In addition, various forestry mathematical models were proposed to deduce forestry canopy indexes based on the radiation transfer model of Beer-Lambert law. Through the comparison of the experimental results on many plot samples, the terrestrial laser scanner- (TLS-) based index estimation method obtains results similar to digital hemispherical photograph (HP) and LAI-2200 plant canopy analyzer taken of the same stands and used for validation. It indicates that the TLS-based algorithm is able to capture the variability in LAI of forest stands with a range of densities, and there is a high chance to enhance TLS as a calibration tool for other devices.

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