Leaf aging of Amazonian canopy trees as revealed by spectral and physiochemical measurements

Cecilia Chavana-Bryant, Yadvinder Malhi, Jin Wu, Gregory P. Asner, Athanasios Anastasiou, Brian J. Enquist, Eric G. Cosio Caravasi, Christopher E. Doughty, Scott R. Saleska, Roberta E. Martin, France F. Gerard

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Leaf aging is a fundamental driver of changes in leaf traits, thereby regulating ecosystem processes and remotely sensed canopy dynamics. We explore leaf reflectance as a tool to monitor leaf age and develop a spectra-based partial least squares regression (PLSR) model to predict age using data from a phenological study of 1099 leaves from 12 lowland Amazonian canopy trees in southern Peru. Results demonstrated monotonic decreases in leaf water (LWC) and phosphorus (Pmass) contents and an increase in leaf mass per unit area (LMA) with age across trees; leaf nitrogen (Nmass) and carbon (Cmass) contents showed monotonic but tree-specific age responses. We observed large age-related variation in leaf spectra across trees. A spectra-based model was more accurate in predicting leaf age (R2 = 0.86; percent root mean square error (%RMSE) = 33) compared with trait-based models using single (R2 = 0.07–0.73; %RMSE = 7–38) and multiple (R2 = 0.76; %RMSE = 28) predictors. Spectra- and trait-based models established a physiochemical basis for the spectral age model. Vegetation indices (VIs) including the normalized difference vegetation index (NDVI), enhanced vegetation index 2 (EVI2), normalized difference water index (NDWI) and photosynthetic reflectance index (PRI) were all age-dependent. This study highlights the importance of leaf age as a mediator of leaf traits, provides evidence of age-related leaf reflectance changes that have important impacts on VIs used to monitor canopy dynamics and productivity and proposes a new approach to predicting and monitoring leaf age with important implications for remote sensing.

Original languageEnglish (US)
Pages (from-to)1049-1063
Number of pages15
JournalNew Phytologist
Volume214
Issue number3
DOIs
StatePublished - May 1 2017
Externally publishedYes

Fingerprint

canopy
leaves
Peru
Water
Least-Squares Analysis
Phosphorus
Ecosystem
Nitrogen
Carbon
reflectance
monitoring
tree age
remote sensing
least squares
lowlands
water
phosphorus
ecosystems
carbon
nitrogen

Keywords

  • canopy trees
  • leaf age
  • leaf lifecycle
  • leaf spectral properties
  • leaf traits
  • phenology
  • tropical forests
  • vegetation indices (VIs)

ASJC Scopus subject areas

  • Physiology
  • Plant Science

Cite this

Chavana-Bryant, C., Malhi, Y., Wu, J., Asner, G. P., Anastasiou, A., Enquist, B. J., ... Gerard, F. F. (2017). Leaf aging of Amazonian canopy trees as revealed by spectral and physiochemical measurements. New Phytologist, 214(3), 1049-1063. https://doi.org/10.1111/nph.13853

Leaf aging of Amazonian canopy trees as revealed by spectral and physiochemical measurements. / Chavana-Bryant, Cecilia; Malhi, Yadvinder; Wu, Jin; Asner, Gregory P.; Anastasiou, Athanasios; Enquist, Brian J.; Cosio Caravasi, Eric G.; Doughty, Christopher E.; Saleska, Scott R.; Martin, Roberta E.; Gerard, France F.

In: New Phytologist, Vol. 214, No. 3, 01.05.2017, p. 1049-1063.

Research output: Contribution to journalArticle

Chavana-Bryant, C, Malhi, Y, Wu, J, Asner, GP, Anastasiou, A, Enquist, BJ, Cosio Caravasi, EG, Doughty, CE, Saleska, SR, Martin, RE & Gerard, FF 2017, 'Leaf aging of Amazonian canopy trees as revealed by spectral and physiochemical measurements', New Phytologist, vol. 214, no. 3, pp. 1049-1063. https://doi.org/10.1111/nph.13853
Chavana-Bryant, Cecilia ; Malhi, Yadvinder ; Wu, Jin ; Asner, Gregory P. ; Anastasiou, Athanasios ; Enquist, Brian J. ; Cosio Caravasi, Eric G. ; Doughty, Christopher E. ; Saleska, Scott R. ; Martin, Roberta E. ; Gerard, France F. / Leaf aging of Amazonian canopy trees as revealed by spectral and physiochemical measurements. In: New Phytologist. 2017 ; Vol. 214, No. 3. pp. 1049-1063.
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