@article{68aeb5daaf4442ebb5c3fde36af1f2c9,
title = "Developmental changes in the reflectance spectra of temperate deciduous tree leaves and implications for thermal emissivity and leaf temperature",
abstract = "Leaf optical properties impact leaf energy balance and thus leaf temperature. The effect of leaf development on mid-infrared (MIR) reflectance, and hence thermal emissivity, has not been investigated in detail. We measured a suite of morphological characteristics, as well as directional-hemispherical reflectance from ultraviolet to thermal infrared wavelengths (250 nm to 20 µm) of leaves from five temperate deciduous tree species over the 8 wk following spring leaf emergence. By contrast to reflectance at shorter wavelengths, the shape and magnitude of MIR reflectance spectra changed markedly with development. MIR spectral differences among species became more pronounced and unique as leaves matured. Comparison of reflectance spectra of intact vs dried and ground leaves points to cuticular development – and not internal structural or biochemical changes – as the main driving factor. Accompanying the observed spectral changes was a drop in thermal emissivity from about 0.99 to 0.95 over the 8 wk following leaf emergence. Emissivity changes were not large enough to substantially influence leaf temperature, but they could potentially lead to a bias in radiometrically measured temperatures of up to 3 K. Our results also pointed to the potential for using MIR spectroscopy to better understand species-level differences in cuticular development and composition.",
keywords = "Fourier transform infrared (FT-IR), cuticle, directional-hemispherical reflectance (DHR), leaf development, leaf temperature, mid-infrared (MIR), phenology, thermal remote sensing",
author = "Richardson, {Andrew D.} and Aubrecht, {Donald M.} and David Basler and Koen Hufkens and Muir, {Christopher D.} and Leonard Hanssen",
note = "Funding Information: This work was supported by funding from the National Science Foundation{\textquoteright}s Macrosystems Biology (1241616) and LTER (1637685) programmes. We thank Mark Friedl (Boston University), three internal NIST reviewers and three anonymous referees for valuable feedback on drafts of this manuscript. Disclaimer: Certain commercial equipment, instruments or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. Funding Information: This work was supported by funding from the National Science Foundation?s Macrosystems Biology (1241616) and LTER (1637685) programmes. We thank Mark Friedl (Boston University), three internal NIST reviewers and three anonymous referees for valuable feedback on drafts of this manuscript. Disclaimer: Certain commercial equipment, instruments or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. Publisher Copyright: {\textcopyright} 2020 The Authors New Phytologist {\textcopyright} 2020 New Phytologist Trust",
year = "2021",
month = jan,
doi = "10.1111/nph.16909",
language = "English (US)",
volume = "229",
pages = "791--804",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley-Blackwell",
number = "2",
}