RT Journal Article SR Electronic T1 Enhancing the Precision and Spatial Acuity of Point Quadrat Analyses via Calibrated Exposure Mapping JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 425 OP 431 DO 10.5344/ajev.2008.59.4.425 VO 59 IS 4 A1 James M. Meyers A1 Justine E. Vanden Heuvel YR 2008 UL http://www.ajevonline.org/content/59/4/425.abstract AB Modeling canopy sunlight environments requires precise measurements of biomass distribution and photon flux distribution (PFD). However, customary methods for obtaining these measurements are limited in their precision and practicality. Point quadrat analysis (PQA), the standard for canopy architecture, is limited in spatial precision and the lack of calibration; while measurement of PFD across an entire canopy typically requires rigorous sampling protocols. New methods are introduced that combine PQA and photon flux measurements into a calibrated biomass and PFD model. These techniques, applied to sample data from a shoot-thinning study, revealed quantitative descriptions of canopy biomass distribution, light environment, and treatment efficacy.