Optimization of Leaf Area Estimation in a High-Density Apple Orchard Using Hemispherical Photography

in HortScience

Leaf area is evaluated as leaf area index (LAI), the ratio of leaf to ground area, and is known to be crucial to understanding forests and high-quality fruit production in orchards. Nondestructive tools have been available for decades that pair hemispherical photography with gap fraction theories to understand LAI. Those tools do not allow for rapid assessment in the field, and there is no standardized protocol to acquire accurate estimates yet. This experiment has developed an optimized method with the CID Plant Canopy Imager (CI-110) in a high-density apple orchard. This novel tool for LAI estimation allows image acquisition and processing in real time in the field. LAI assessments of hemispherical images were taken under five light environments, at three imaging heights, processed with two thresholding methods, and were compared with destructive LAI values for accuracy. The difference between estimated and destructive LAI (∆LAI) was determined for trees on an individual or grouped by a three tree basis. Estimations for triplet groupings were more accurate, and the significantly lower ∆LAI in each treatment occurred for the no-net environment, 10 cm from the ground and processed with the Otsu threshold. When combined as triplet groupings, this methodology sequence yielded an LAI estimation with a 13% prediction error (∆LAI = 0.19). The use of the CI-110 with this methodology can give useful, real-time information regarding orchard canopies to address pruning and training decisions for high-quality fruit production.

Contributor Notes

This research was funded by the Washington Tree Fruit Research Commission with project number # AP14-103A and WSDA Specialty Crop Block Grant Agreement Number: K1767.Mention of a proprietary product or vendor does not constitute a guarantee or warranty of the product by Washington State University and does not imply its approval to the exclusion of other products or vendors that also may be suitable.

These authors contributed equally to this work and are co-authors.

Corresponding author. E-mail: Stefano.musacchi@wsu.edu.

  • BarrittB.H.1989Influence of orchard system on canopy development, light interception and production of third-year Granny Smith apple treesActa Hort.243121130

    • Search Google Scholar
    • Export Citation
  • BrédaN.J.2003Ground-based measurements of leaf area index: A review of methods, instruments and current controversiesJ. Expt. Bot.5424032417

    • Search Google Scholar
    • Export Citation
  • ChianucciF.CutiniA.2012Digital hemispherical photography for estimating forest canopy properties: Current controversies and opportunitiesIForest (Viterbo)5290295

    • Search Google Scholar
    • Export Citation
  • CutiniA.VaralloA.2006Estimation of foliage characteristics of isolated trees with the Plant Canopy Analyzer LAI-2000Ecology14956

  • FangM.YueG.YuQ.2009The study on an application of Otsu method in canny operator. Proc. 2009 Intl. Symp. Info. Processing 109–112

  • FaustM.1989Physiology of temperate zone fruit trees. Wiley Hoboken NJ

  • GoswamiS.GamonJ.A.VargasS.TweedieC.E.2015Relationships of NDVI biomass and leaf area index (LAI) for six key plant species in Barrow Alaska. PeerJ PrePrints <https://doi.org/10.7287/peerj.preprints.913v1>

  • HeinickeA.J.1964The microclimate of fruit trees III the effect of tree size on light penetration and leaf area in red delicious apple treesProc. Amer. Soc. Hort. Sci.853341

    • Search Google Scholar
    • Export Citation
  • JacksonJ.E.1978Utilization of light resources by HDP systemsActa Hort.656170

  • JonckheereI.FleckS.NackaertsK.MuysB.CoppinP.WeissM.BaretF.2004Review of methods for in situ leaf area index determination Part I: Theories, sensors and hemispherical photographyAgr. For. Meteorol.1211935

    • Search Google Scholar
    • Export Citation
  • JonckheereI.NackaertsK.MuysB.CoppinP.2005Assessment of automatic gap fraction estimation of forests from digital hemispherical photographyAgr. For. Meteorol.13296114

    • Search Google Scholar
    • Export Citation
  • KeaneR.E.ReinhardtE.D.ScottJ.GrayK.ReardonJ.2005Estimating forest canopy bulk density using six indirect methodsCan. J. For. Res.35724739

    • Search Google Scholar
    • Export Citation
  • LaksoA.N.1976Characterizing apple tree canopies by fisheye photographyHortScience11404405

  • LaksoA.N.1980Correlations of fisheye photography to canopy structure, light climate, and biological responses to light in apple treesJ. Amer. Soc. Hort. Sci.1054346

    • Search Google Scholar
    • Export Citation
  • LiuC.KangS.LiF.LiS.DuT.2013Canopy leaf area index for apple tree using hemispherical photography in arid regionScientia Hort.164610615

    • Search Google Scholar
    • Export Citation
  • MariniR.P.BardenJ.A.1982Growth and flowering of vigorous apple tree affected by summer and dormant pruningJ. Amer. Soc. Hort. Sci.1073439

    • Search Google Scholar
    • Export Citation
  • MusacchiS.GreenD.2017Innovations in apple tree cultivation to manage crop load and ripening p. 195–237. In: K. Evans (ed.). Achieving sustainable cultivation of apples. Burleigh Dodds Science Publishing Cambridge UK

  • NormanJ.M.CampbellG.S.1989Canopy structure p. 301–325. In: R.W. Pearcy J. Ehlringer H.A. Mooney and P.W. Rundel (eds.). Plant ecology: Field methods and instrumentation. Chapman & Hall London UK

  • Poblete-EcheverríaC.FuentesS.Ortega-FariasS.Gonzalez-TaliceJ.YuriJ.A.2015Digital cover photography for estimating leaf area index (LAI) in apple trees using a variable light extinction coefficientAgr. For.: Sensors Technologies Procedures1528602872

    • Search Google Scholar
    • Export Citation
  • RichP.M.1988Video image analysis of hemispherical canopy photography. Proc. First Special Wkshp. Videography 84–95

  • RobinsonT.SeeleyE.BarrittB.1983Effect of light environment and spur age on “Delicious” apple fruit size and qualityJ. Amer. Soc. Hort. Sci.108855861

    • Search Google Scholar
    • Export Citation
  • RobinsonT.L.LaksoA.N.RenZ.1991Modifying apple tree canopies for improved production efficiencyHortScience2610051012

  • RobinsonT.L.WünscheJ.LaksoA.1993The influence of orchard system and pruning severity on yield, light interception, conversion efficiency, partitioning index and leaf area indexActa Hort.349123128

    • Search Google Scholar
    • Export Citation
  • SaureM.C.1987Summer pruning effect on apple: A reviewScientia Hort.30253282

  • SezginM.SankurB.2004Survey over image thresholding techniques and quantitative performance evaluationJ. Electron. Imaging131146165

  • VerheijE.W.M.VerwerF.L.J.A.W.1973Light studies in a spacing trial with apple on a dwarfing and a semi-dwarfing rootstockScientia Hort.112542

    • Search Google Scholar
    • Export Citation
  • WoodgateW.Soto-BerelovM.SuarezL.JonesS.HillM.WilkesP.AxelssonC.HaywoodA.MellorA.2012Searching for the optimal sampling design for measuring LAI in an upland rainforest. Proc. 2012 Geospatial Sci. Res. Symp. GSR2

  • WünscheJ.N.LaksoA.N.RobinsonT.L.1995Comparison of four methods for estimating total light interception by apple trees of varying formsHortScience30272276

    • Search Google Scholar
    • Export Citation
  • WünscheJ.N.PalmerJ.W.1997Comparison of non-destructive methods of estimating leaf area in apple tree canopiesActa Hort.451701708

  • ZhangY.ChenJ.M.MillerJ.R.2005Determining digital hemispherical photograph exposure for leaf area index estimationAgr. For. Meteorol.133166181

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 240 240 23
Full Text Views 77 77 0
PDF Downloads 27 27 0