Name: field measurement of effective leaf area index using optical device in vegetation canopy
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Description: Watch this Scientific Journal Video about Field Measurement of Effective Leaf Area Index using Optical Device in Vegetation Canopy at JoVE.com

The authors are indebted to the Journal of Forest Science editorial board for encouraging and authorizing us to use the representative results in this protocol from the article published there.
The research was financially supported by the Ministry of Agriculture of the Czech Republic, institutional support MZE-RO0118, National Agency of Agricultural Research (Project No. QK21020307), and the European Union&#39;s Horizon 2020 research and innovation program (grant agreement No. 952314).
The authors also kindly thank three anonymous reviewers for their constructive criticism, which improved the manuscript. In addition, thanks go to Dusan Bartos, Alena Hvezdova, and Tomas Petr for helping with field measurements and Photon Systems Instruments Ltd. company for their collaboration and providing device photos.

NOTE: Before beginning to take planned field measurements, sufficiently charge the battery of the LP 110 device. Connect the instrument (USB connector, see Figure 1) and the computer through the attached cable. Battery status is shown in the left-upper corner of the device display.
1. Calibration before measurement
NOTE: For the LP 110, perform a dark calibration of the LAI sensor and in-built inclinometer calibrations before beginning ea...

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	<li>Muiruri, E. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forest+diversity+effects+on+insect+herbivores:+Do+leaf+traits+matter.">Forest diversity effects on insect herbivores: Do leaf traits matter.</a> New Phytologist. 221 (4), 2250-2260 (2018).</li><li>Macfarlane, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+leaf+area+index+in+eucalypt+forest+using+digital+photography.">Estimation of leaf area index in eucalypt forest using digital photography.</a> Agricultural and Forest Meteorology. 143 (3-4), 176-188 (2007).</li><li>Easlon, H. M., Bloom, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Easy+leaf+area:+Automated+digital+image+analysis+for+rapid+and+accurate+measurements+of+leaf+area.">Easy leaf area: Automated digital image analysis for rapid and accurate measurements of leaf area.</a> Applications in Plant Sciences. 2 (7), 1400033 (2014).</li><li>Asner, G. P., Scurlock, J. M. O., Hicke, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+synthesis+of+leaf+area+index+observations:+implications+for+ecological+and+remote+sensing+studies.">Global synthesis of leaf area index observations: implications for ecological and remote sensing studies.</a> Global Ecology and Biogeography. 12, 191-205 (2003).</li><li>Vicari, M. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leaf+and+wood+classification+framework+for+terrestrial+LiDAR+point+clouds.">Leaf and wood classification framework for terrestrial LiDAR point clouds.</a> Methods in Ecology and Evolution. 10 (5), 680-694 (2019).</li><li>Watson, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+physiological+studies+in+the+growth+of+field+crops.+I.+Variation+in+net+assimilation+rate+and+leaf+area+between+species,+varieties,+and+within+and+between+years.">Comparative physiological studies in the growth of field crops. I. Variation in net assimilation rate and leaf area between species, varieties, and within and between years.</a> Annals of Botany. 11, 41-76 (1947).</li><li>Chen, J. M., Black, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+leaf-area+index+for+non-flat+leaves.">Defining leaf-area index for non-flat leaves.</a> Plant, Cell and Environment. 15 (4), 421-429 (1992).</li><li>Welles, J. M., Cohen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Canopy+structure+measurement+by+gap+fraction+analysis+using+commercial+instrumentation.">Canopy structure measurement by gap fraction analysis using commercial instrumentation.</a> Journal of Experimental Botany. 47 (9), 1335-1342 (1996).</li><li>Br&#233;da, N. J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ground-based+measurements+of+leaf+area+index:+a+review+of+methods,+instruments,+and+current+controversies.">Ground-based measurements of leaf area index: a review of methods, instruments, and current controversies.</a> Journal of Experimental Botany. 54 (392), 2403-2417 (2003).</li><li>Jonckheere, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+methods+for+in+situ+leaf+area+index+determination.+Part+I:+Theories,+sensors+and+hemispherical+photography.">Review of methods for in situ leaf area index determination. Part I: Theories, sensors and hemispherical photography.</a> Agricultural and Forest Meteorology. 121 (1-2), 19-35 (2004).</li><li>Weiss, M., Baret, F., Smith, G. J., Jonckheere, I., Coppin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+methods+for+in+situ+leaf+area+index+(LAI)+determination.+Part+II.+Estimation+of+LAI,+errors+and+sampling.">Review of methods for in situ leaf area index (LAI) determination. Part II. Estimation of LAI, errors and sampling.</a> Agricultural and Forest Meteorology. 121 (1-2), 37-53 (2004).</li><li>Fang, H., Baret, F., Plummer, S., Schaepman-Strub, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+global+leaf+area+index+(LAI):+Methods,+products,+validation,+and+applications.">An overview of global leaf area index (LAI): Methods, products, validation, and applications.</a> Reviews of Geophysics. 57 (3), 739-799 (2019).</li><li>Yan, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+indirect+optical+measurements+of+leaf+area+index:+Recent+advances,+challenges,+and+perspectives.">Review of indirect optical measurements of leaf area index: Recent advances, challenges, and perspectives.</a> Agricultural and Forest Meteorology. 265, 390-411 (2019).</li><li>Parker, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tamm+review:+Leaf+Area+Index+(LAI)+is+both+a+determinant+and+a+consequence+of+important+processes+in+vegetation+canopies.">Tamm review: Leaf Area Index (LAI) is both a determinant and a consequence of important processes in vegetation canopies.</a> Forest Ecology and Management. 477, 118496 (2020).</li><li>Jiapaer, G., Yi, Q., Yao, F., Zhang, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+non-destructive+LAI+determination+methods+and+optimization+of+sampling+schemes+in+an+open+Populus+euphratica+ecosystem.">Comparison of non-destructive LAI determination methods and optimization of sampling schemes in an open Populus euphratica ecosystem.</a> Urban Forestry and Urban Greening. 26, 114-123 (2017).</li><li>Grotti, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+intensity,+image-based+method+to+estimate+gap+fraction,+canopy+openness+and+effective+leaf+area+index+from+phase-shift+terrestrial+laser+scanning.">An intensity, image-based method to estimate gap fraction, canopy openness and effective leaf area index from phase-shift terrestrial laser scanning.</a> Agricultural and Forest Meteorology. 280, 107766 (2020).</li><li>Gower, S. T., Kucharik, C. J., Norman, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+and+indirect+estimation+of+leaf+area+index,+fAPAR,+and+net+primary+production+of+terrestrial+ecosystems.">Direct and indirect estimation of leaf area index, fAPAR, and net primary production of terrestrial ecosystems.</a> Remote Sensing of Environment. 70 (1), 29-51 (1999).</li><li>Morisette, J. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+global+moderate-resolution+LAI+products:+a+framework+proposed+within+the+CEOS+land+product+validation+subgroup.">Validation of global moderate-resolution LAI products: a framework proposed within the CEOS land product validation subgroup.</a> IEEE Transactions on Geoscience and Remote Sensing. 44 (7), 1804-1817 (2006).</li><li>Pokorn&#253;, R., &#352;alansk&#225;, P., Janou&#353;, D., Pavelka, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ALAI-02D+-+a+new+instrument+in+forest+practice.">ALAI-02D - a new instrument in forest practice.</a> Journal of Forest Science. 47, 164-169 (2001).</li><li>&#268;ern&#253;, J., Krejza, J., Pokorn&#253;, R., Bedn&#225;&#345;, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LaiPen+LP+100+-+a+new+device+for+estimating+forest+ecosystem+leaf+area+index+compared+to+the+etalon:+A+methodologic+case+study.">LaiPen LP 100 - a new device for estimating forest ecosystem leaf area index compared to the etalon: A methodologic case study.</a> Journal of Forest Science. 64 (11), 455-468 (2018).</li><li>Larcher, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Physiological plant ecology. Ecophysiology and Stress Physiology of Functional Groups. , (2003).</li><li>Taiz, L., Zeiger, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Plant Physiology. 5th edition. , 623 (2010).</li><li>Pokorn&#253;, R., Tom&#225;&#353;kov&#225;, I., Havr&#225;nkov&#225;, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+variation+and+efficiency+of+leaf+area+index+in+young+mountain+Norway+spruce+stand.">Temporal variation and efficiency of leaf area index in young mountain Norway spruce stand.</a> European Journal of Forest Research. 127, 359-367 (2008).</li><li>Chen, J. M., Black, T. A., Adams, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+hemispherical+photography+for+determining+plant+area+index+and+geometry+of+a+forest+stand.">Evaluation of hemispherical photography for determining plant area index and geometry of a forest stand.</a> Agricultural and Forest Meteorology. 56, 129-143 (1991).</li><li>Black, T. A., Chen, J. M., Lee, X. H., Sagar, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characteristics+of+shortwave+and+longwave+irradiances+under+a+Douglas-fir+forest+stand.">Characteristics of shortwave and longwave irradiances under a Douglas-fir forest stand.</a> Canadian Journal of Forest Research. 21 (7), 1020-1028 (1991).</li><li>Hirose, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+the+Monsi-Saeki+theory+on+canopy+structure+and+function.">Development of the Monsi-Saeki theory on canopy structure and function.</a> Annals of Botany. 95 (3), 483-494 (2005).</li><li>Pierce, L., Running, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=rapid+estimation+of+coniferous+forest+leaf+area+index+using+a+portable+integrating+radiometer.">rapid estimation of coniferous forest leaf area index using a portable integrating radiometer.</a> Ecology. 69 (6), 1762-1767 (1988).</li><li>Lang, A. R. G., McMurtrie, R. E., Benson, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validity+of+surface-area+indexes+of+Pinus+radiata+estimated+from+transmittance+of+sun's+beam.">Validity of surface-area indexes of Pinus radiata estimated from transmittance of sun's beam.</a> Agricultural and Forest Meteorology. 57 (1-3), 157-170 (1991).</li><li>Zou, J., Yan, G., Zhu, L., Zhang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Woody-to-total+area+ratio+determination+with+a+multispectral+canopy+imager.">Woody-to-total area ratio determination with a multispectral canopy imager.</a> Tree Physiology. 29 (8), 1069-1080 (2009).</li><li>Stenberg, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correcting+LAI-2000+estimates+for+the+clumping+of+needles+in+shoots+of+conifer.">Correcting LAI-2000 estimates for the clumping of needles in shoots of conifer.</a> Agricultural and Forest Meteorology. 79 (1-2), 1-8 (1996).</li><li>Chianucci, F., MacFarlane, C., Pisek, J., Cutini, A., Casa, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+foliage+clumping+from+the+LAI-2000+Plant+Canopy+Analyser:+effect+of+view+caps.">Estimation of foliage clumping from the LAI-2000 Plant Canopy Analyser: effect of view caps.</a> Trees-Structure and Function. 29, 355-366 (2015).</li><li>Zou, J., Yan, G., Chen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+canopy+and+woody+components+clumping+indices+at+three+mature+Picea+crassifolia+forest+stands.">Estimation of canopy and woody components clumping indices at three mature Picea crassifolia forest stands.</a> IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 8 (4), 1413-1422 (2015).</li><li>Bao, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+tree+trunks+on+estimation+of+clumping+index+and+LAI+from+HemiView+and+Terrestrial+LiDAR.">Effects of tree trunks on estimation of clumping index and LAI from HemiView and Terrestrial LiDAR.</a> Forests. 9 (3), 144 (2018).</li><li>Zhu, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+leaf+area+index+(LAI)+estimation+by+correcting+for+clumping+and+woody+effects+using+terrestrial+laser+scanning.">Improving leaf area index (LAI) estimation by correcting for clumping and woody effects using terrestrial laser scanning.</a> Agricultural and Forest Meteorology. 263, 276-286 (2018).</li><li>Photon Systems Instruments Ltd. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> PSI LaiPen LP 110 Manual and User Guide. , 45 (2016).</li><li>&#268;ern&#253;, J., Pokorn&#253;, R., Haninec, P., Bedn&#225;&#345;, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leaf+area+index+estimation+using+three+distinct+methods+in+pure+deciduous+stands.">Leaf area index estimation using three distinct methods in pure deciduous stands.</a> Journal of Visualized Experiments: JoVE. (150), e59757 (2019).</li><li>Fleck, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leaf+area+measurements.+Manual+Part+XVII.+In:+UNECE+ICP+Forests+Programme+Co-ordinating+Centre+(Ed.)+Manual+of+methods+and+criteria+for+harmonized+sampling,+assessment,+monitoring+and+analysis+of+the+effects+of+air+pollution+on+forests.">Leaf area measurements. Manual Part XVII. In: UNECE ICP Forests Programme Co-ordinating Centre (Ed.) Manual of methods and criteria for harmonized sampling, assessment, monitoring and analysis of the effects of air pollution on forests.</a> Th&#252;nen Institute of Forest Ecosystems. , (2016).</li><li>&#268;ern&#253;, J., Pokorn&#253;, R., Haninec, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leaf+area+index+estimated+by+direct,+semi-direct,+and+indirect+methods+in+European+beech+and+sycamore+maple+stands.">Leaf area index estimated by direct, semi-direct, and indirect methods in European beech and sycamore maple stands.</a> Journal of Forestry Research. 31, 827-836 (2020).</li><li>Leblanc, S. G., Chen, J. M., Kwong, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracing+radiation+and+architecture+of+canopies.">Tracing radiation and architecture of canopies.</a> TRAC MANUAL Version 2.1.3. , 25 (2002).</li><li>Sommer, K. J., Lang, A. R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+analysis+of+two+indirect+methods+of+measuring+leaf+area+index+as+applied+to+minimal+and+spur+pruned+grape+vines.">Comparative analysis of two indirect methods of measuring leaf area index as applied to minimal and spur pruned grape vines.</a> Australian Journal of Plant Physiology. 21 (2), 197-206 (1994).</li><li>Leblanc, S. G., Chen, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+scheme+for+correcting+multiple+scattering+effects+on+optical+LAI+measurements.">A practical scheme for correcting multiple scattering effects on optical LAI measurements.</a> Agricultural and Forest Meteorology. 110 (2), 125-139 (2001).</li></ol>

What are the differences between the LP 110 as a newly presented device for estimating LAI (or taking PAR intensity measurements) and the LAI-2200 PCA as an improved version of the previous standard LAI-2000 PCA for estimating LAI via an indirect method? Beyond the price being about fourfold higher for the Plant Canopy Analyzer compared to the LP 110, the number of output parameters, measurement conditions, methodological approaches, and possibilities of estimating LAI for different canopies, accuracy of results, etc., c...

Canopies are loci of numerous biological, physical, chemical, and ecological processes. Most of them are affected by canopy structures1. Therefore, accurate, rapid, non-destructive, and reliable in situ&#160;vegetation canopy quantification is crucial for a wide range of studies involving hydrology, carbon and nutrient cycling, and global climate change2,3. Since leaves or needles represent an active interface between the atmosphere and vegetation4, one of the critical canopy structural characteristics is leaf area index (LAI)5, defined as one-half of the total green leaf surface area per unit of horizontal ground surface area or crown projection for individuals, expressed in m2 per m2 as a dimensionless variable6,7.
Various instruments and methodological approaches for estimating terrestrial LAI and their pros and cons in diverse ecosystems have already been presented8,9,10,11,12,13,14,15. There are two main categories of LAI estimation methods: direct and indirect (see comprehensive reviews8,9,10,11,12 for more details). Mainly used in forest stands, ground-based&#160;LAI estimates are routinely obtained using indirect optical methods due to the lack of direct LAI determination, but they usually represented a time-consuming, labor-intensive, and destructive method9,10,12,16. Moreover, indirect optical methods derive LAI from more easily measure related parameters (from the viewpoint of its time-demanding and labor-intense nature)17, such as the ratio between incident irradiation above and below the canopy and the quantification of canopy gaps14. It is evident that Plant Canopy Analyzers have also been widely used to validate satellite LAI retrievals18; therefore, it has been considered a standard for LP 110 comparison (see Table of Materials for more details about employed instruments).
The LP 110, as an updated version of initially self-made simple instrument ALAI-02D19 and later LP 10020, was developed as a close competitor for Plant Canopy Analyzers. As a representative of indirect optical methods, the device is hand-held, lightweight, battery-powered, without any need for a cable connection between the sensor and data-logger that uses a digital inclinometer instead of a bubble level and enables faster and more accurate positioning and value reading. In addition, the device was designed to note immediate readouts. Thus, the time estimate needed for collecting data in the field is shorter for the LP 110 than Plant Canopy Analyzer by approximately &#8531;. After the export of readouts to a computer, the data are available for subsequent processing. The device records irradiance within the blue light wavelengths (i.e., 380-490 nm)21,22 using an LAI sensor for making an LAI calculation. The LAI sensor is masked by an opaque restriction cap with 16&#176; (Z-axis) and 112&#176; (X-axis) fields of view (Figure 1). Thus, light transmittance can be noted using the device held either perpendicularly to the ground surface (i.e., zenith angle 0&#176;), or at five different angles of 0&#176;, 16&#176;, 32&#176;, 48&#176;, and 64&#176; to be able also to deduce canopy elements&#39; inclination.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62802/62802fig01.jpg" /> 
Figure 1: Physical features of the LP 110. The MENU key enables the user shift up and down throughout the display, and the SET button serves as the Enter key (A).The zenith view under different inclination angles (&#177;8 due to the side view) and the horizontal view is fixed for LP 110 to 112&#176; (B) similarly to the Plant Canopy Analyzer&#160;(modified by restrictors). <a href="https://www.jove.com/files/ftp_upload/62802/62802fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Due to the higher sensitivity of the LAI sensor, its restricted field of view, in-built digital inclinometer, automatic logging of reading values at the correct position indicated by sound without a button press, the new instrument is also suitable for above-canopy readings at narrow valleys or even on broader forest roads to measure a wide range of sky conditions. Besides that, it enables quantification of mature stand canopies above the relatively high regeneration, and it attains higher accuracy of irradiance values than Plant Canopy Analyzer. Moreover, the price of LP 110 equals about &#188; of the Plant Canopy Analyzer. Contrariwise, the utilization of LP 110 in dense (i.e.,&#160;LAIe at stand level over 7.88)23 or very low canopies as grassland is limited.
The LP 110 can work within two operating modes: (i) a single sensor mode taking both below-canopy and reference readings (above the studied canopy or in a sufficiently widespread clearing located within the vicinity of the analyzed vegetation) performed before, after, or during below-canopy measurements taken with the same instrument and (ii) a dual sensor mode using the first instrument for taking below-canopy readings, whereas the second one is employed for automatically logging reference readings within a regular predefined time interval (from 10 up to 600 s). The LP 110 can be matched with a compatible GPS device (see Table of Materials) to record each below-canopy measurement point&#39;s coordinates for both the modes mentioned above.
The effective leaf area index (LAIe)24 incorporates the clumping index effect and can be derived from measurements of solar beam irradiance taken above and below the studied vegetation canopy25. Thus, for the following LAIe calculation, transmittance (t) must be calculated from irradiation both transmitted below the canopy (I) and incident above the vegetation (Io) measured by the LP 110 device.
t = I / I0 (1)
Since the irradiation intensity exponentially decreases as it passes through a vegetation canopy, LAIe can be calculated according to the Beer-Lambert extinction law modified by Monsi and Saeki9,26
LAIe = - ln (I / I0) x k-1 (2),
Where, k is the extinction coefficient. The extinction coefficient reflects each element&#39;s shape, orientation, and position in the vegetation canopy with the known canopy element inclination and view direction9,12. The k coefficient (see equation 2) depends on the absorption of irradiance by foliage, and it differs among plant species based on the morphological parameters of canopy elements, their spatial arrangement, and optical properties. Since the extinction coefficient usually fluctuates around 0.59,27, equation 2 can be simplified as presented by Lang et al.28 in a slightly different way for heterogeneous and homogenous canopies:
In a heterogeneous canopy
LAIe = 2 x |<img alt="Equation 1" src="/files/ftp_upload/62802/62802eq01.jpg" />ln t| (3),
or
In a homogeneous canopy
LAIe = 2 x |ln T| (4),
Where, t: is transmittance at each below-canopy measurement point, and T: is the average transmittance of all t values per measured transect or stand.
In forest stands, LAIe must be further corrected due to a clumping effect of the assimilation apparatus within the shoots29,30,31,32,33,34 to obtain the actual LAI value.
The protocol is devoted to the practical utilization of the LP 110 optical device for estimating LAIe in a selected example of Central European conifer forest stands (see Table 2 and Table 3 for the site, structural, and dendrometric characteristics). LAIe estimation in a vegetation canopy using this device is based on a widely used optical method related to the transmittance of photosynthetically active radiation and canopy gap fraction. The paper aims to provide a comprehensive protocol for performing LAIe estimation using the new LP 110 optical device.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>AccuPAR</td>
			<td>METER Group, Inc., Pullman, WA, USA</td>
			<td>AccuPaR LP-80</td>
			<td>https://www.metergroup.com/environment/products/accupar-lp-80-leaf-area-index/</td>
		</tr>
		<tr>
			<td>DEMON</td>
			<td>CSIRO, Canberra, Australia</td>
			<td>DEMON</td>
			<td></td>
		</tr>
		<tr>
			<td>File Viewer</td>
			<td>LI-COR Biosciences Inc., NE, USA</td>
			<td>FV2200C Software</td>
			<td>https://www.licor.com/env/products/leaf_area/LAI-2200C/software.html</td>
		</tr>
		<tr>
			<td>FluorPen</td>
			<td>Photon System Instruments Ltd. (PSI), Czech Republic</td>
			<td>FluorPen 1.1.2.3 Sofware</td>
			<td>https://handheld.psi.cz/products/laipen/#download</td>
		</tr>
		<tr>
			<td>Hand-held GPS device</td>
			<td>Garmin Ltd., Czech Republic</td>
			<td>Garmin eTrex 32x Europe46</td>
			<td>https://www.garmin.cz/garmin-etrex-32x-europe46/80117</td>
		</tr>
		<tr>
			<td>Hand-held device for leaf area index estimation(LP 110)</td>
			<td>Photon System Instruments Ltd. (PSI) Czech Republic</td>
			<td>LaiPen LP 110</td>
			<td>https://handheld.psi.cz/products/laipen/#info</td>
		</tr>
		<tr>
			<td>Plant Canopy Analyser</td>
			<td>LI-COR Biosciences Inc., NE, USA</td>
			<td>LAI-2000 PCA</td>
			<td>LAI-2200 PCA or LAI-2200C as improved versions of LAI-2000 PCA can be used, see: https://www.licor.com/env/products/leaf_area/LAI-2200C/</td>
		</tr>
		<tr>
			<td>Statistical software</td>
			<td>Systat Software Inc., CA, USA</td>
			<td>SigmaPlot 13.0</td>
			<td>https://systatsoftware.com/products/sigmaplot/sigmaplot-version-13/?gclid=Cj0KCQjwzYGGBhCTARIs 
			AHdMTQzgfb42vv0mWmcbVcflNO 
			UvrLl802Lrhkfh23Qie2mIZfw4O8kp 
			7p0aAsoiEALw_wcB</td>
		</tr>
		<tr>
			<td>Statistical software</td>
			<td>StatSoft Inc., OK, USA</td>
			<td>STATISTICA 10.0</td>
			<td>For LAI visualization, wafer-plots in STATISTICA 10.0 were employed.</td>
		</tr>
		<tr>
			<td>SunScan</td>
			<td>Delta-T Devices, Ltd., Cambridge, UK</td>
			<td>SS1 SunScan</td>
			<td>https://www.delta-t.co.uk/product/sunscan</td>
		</tr>
		<tr>
			<td>TRAC</td>
			<td>3rd Wave Engineering, Ontarion Canada</td>
			<td>Tracing Radiation and Architecture of Canopies</td>
			<td>http://faculty.geog.utoronto.ca/Chen/Chen&#39;s%20homepage/res_trac.htm</td>
		</tr>
		<tr>
			<td>Tripod</td>
			<td>Any</td>
			<td>NA</td>
			<td>Tripod with standard nut</td>
		</tr>
		<tr>
			<td>Water level</td>
			<td>Any</td>
			<td>NA</td>
			<td></td>
		</tr>
	</tbody>
</table>

field measurement of effective leaf area index using optical device in vegetation canopy

Leaf area index (LAI) is an essential canopy variable describing the amount of foliage in an ecosystem. The parameter serves as the interface between green components of plants and the atmosphere, and many physiological processes occur there, primarily photosynthetic uptake, respiration, and transpiration. LAI is also an input parameter for many models involving carbon, water, and the energy cycle. Moreover, ground-based in situ measurements serve as the calibration method for LAI obtained from remote sensing products. Therefore, straightforward indirect optical methods are necessary for making precise and rapid LAI estimates. The methodological approach, advantages, controversies, and future perspectives of the newly developed LP 110 optical device based on the relation between radiation transmitted through the vegetation canopy and canopy gaps were discussed in the protocol. Furthermore, the instrument was compared to the world standard LAI-2200 Plant Canopy Analyzer. The LP 110 enables more rapid and more straightforward processing of data acquired in the field, and it is more affordable than the Plant Canopy Analyzer. The new instrument is characterized by its ease of use for both above- and below-canopy readings due to its greater sensor sensitivity, in-built digital inclinometer, and automatic logging of readings at the correct position. Therefore, the hand-held LP 110 device is a suitable gadget for performing LAI estimation in forestry, ecology, horticulture, and agriculture based on the representative results. Moreover, the same device also enables the user to take accurate measurements of incident photosynthetically active radiation (PAR) intensity.

The spatial structure obtained from both tested devices obviously differed in all studied plots, i.e., thinned from above (A), thinned from below (B) and a control without any silvicultural intervention (C; see Table 2 for more details). At the stand level, similar differences in LAI values obtained from the LP 110 and the Plant Canopy Analyzer were confirmed between thinned plots with various densities (A vs. B) using ANOVA and Tukey&#39;s test. For the Plant Canopy Analyzer, significantly higher LAI va...

Watch this Scientific Journal Video about Field Measurement of Effective Leaf Area Index using Optical Device in Vegetation Canopy at JoVE.com

Field Measurement of Effective Leaf Area Index using Optical Device in Vegetation Canopy

Fast and precise leaf area index (LAI) estimation in terrestrial ecosystems is crucial for a wide range of ecological studies and calibrating remote sensing products. Presented here is the protocol for using the new LP 110 optical device for taking ground-based in situ LAI measurements.

Leaf area index (LAI) is an essential canopy variable describing the amount of foliage in an ecosystem. The parameter serves as the interface between ...

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