Please use this identifier to cite or link to this item: https://repositorio.inpa.gov.br/handle/1/18420
Title: The influence of epiphylls on remote sensing of humid forests
Authors: Toomey, Michael P.
Roberts, Dar A.
Nelson, Bruce Walker
Keywords: Amazon
Caatinga
Canopy Reflectance Modeling
Epifoliar Fungi
Epiphylls
Evi
Modis
Terra Firme
Biomass
Forestry
Fungi
Geologic Models
Infrared Devices
Reflection
Remote Sensing
Spectrometers
Vegetation
Biomass
Caatinga
Canopy Architecture
Canopy Reflectance
Epiphyte
Fungus
Humid Environment
Leaf Area Index
Lichen
Liverwort
Modis
Ndvi
Time Series
Vegetation Cover
Forests
Fungi
Humidification
Infrared Radiation
Leaves
Plants
Reflection
Remote Sensing
Amazonia
South America
Fungi
Marchantiophyta
Issue Date: 2009
metadata.dc.publisher.journal: Remote Sensing of Environment
metadata.dc.relation.ispartof: Volume 113, Número 8, Pags. 1787-1798
Abstract: Epiphylls - lichens, fungi, liverworts, etc. infesting leaf surfaces - are found throughout humid forests of the world. It is well understood that epiphylls inhibit light interception by host plants, but their effect on remote sensing of colonized forests has not been examined. Incorporating leaf-level spectra from Terra Firme (primary forest) and Amazonian Caatinga (woodlands/forest growing on nutrient-deficient sandy soils), we used the GeoSAIL model to propagate leaf-level measurements to the canopy level and determine their effect on commonly used vegetation indices. In Caatinga, moderate infestations (50% leaf area epiphyll cover), lowered simulated Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) values by 6.1% and 20.4%, respectively, largely due to near infrared dampening. Heavy infestation (100% cover) simulations exhibited decreases 1.5-2 times greater than those of moderate infestations. For Terra Firme, which are generally less affected by epiphylls, moderate (20% leaf area) and heavy infestations (40%) lowered EVI by 4.4% (S.D. 0.8%) and 8.1% (S.D. 1.5%), respectively. Near infrared and green reflectance were most affected at the canopy level, showing mean decreases of 10.6% (S.D. 2.25%) and 9.5% (S.D. 3.49%), respectively, in heavy Terra Firme infestations. Time series of Moderate Resolution Imaging Spectrometer (MODIS) data corroborated the modeling results, suggesting a degree of coupling between epiphyll cover and the EVI and NDVI. These results suggest that, without explicit consideration of the presence of epiphylls, remote sensing-based methodologies may underestimate leaf area index, biomass and productivity in humid forests. © 2009 Elsevier Inc. All rights reserved.
metadata.dc.identifier.doi: 10.1016/j.rse.2009.04.002
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