HR: 0800h
AN: B41A-0085    [Abstracts]
TI: Seasonal Changes in Remote Vegetation Indices and Net Photosynthesis of Japanese Larch Needles
AU: Nishida, K
EM: kenlo@sakura.cc.tsukuba.ac.jp
AF: Institute of Agricultural and Forest Engineering, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8572 Japan
AU: * Nakaji, T
EM: nakaji.tatsuro@nies.go.jp
AF: Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Oguma, H
EM: oguma@nies.go.jp
AF: Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Fujinuma, Y
EM: fujinuma@nies.go.jp
AF: Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AB: We investigated the seasonal pattern of four kinds of remote vegetation indices (NDVI, PRI, [(1/rRedEdge)-(1/rNIR)] and [(1/rGreen)-(1/rNIR)]) and their correlation to photosynthetic activity in the needle leaves of Japanese larch. In the 42-year-old larch forest (Tomakomai, Japan), the diurnal courses of spectral reflectance and gas exchange rates of larch needles were periodically investigated during early June to late October in 2003. In the Tomakomai larch forest, expansion of short-shoot needles was started from mid-May, and yellow color change of the needle leaves was observed in late October. The seasonal pattern of index value differed among the vegetation indices. For example, daytime mean NDVI showed constant value from late June to early October. The [(1/rRedEdge)-(1/rNIR)] and PRI were increased during summer, and their peak were observed in July and August, respectively. Although the values of NDVI, PRI and [(1/rRedEdge)-(1/rNIR)] were depressed in late October with autumn senescence of the needles, the [(1/rGreen)-(1/rNIR)] in larch needles was not changed even in yellow colored needles. Consequently, correlation of these vegetation indices and seasonal changed photosynthetic parameters such as net photosynthetic rate (Pn) and photosynthetic light use efficiency (LUE) also differed among the indices. Although the PRI, NDVI and [(1/rRedEdge)-(1/rNIR)] positively correlated with daily maximum Pn and daily means of Pn and LUE, no correlation was found between [(1/rGreen)-(1/rNIR)] and the measured photosynthetic parameters. Based on the results of Pearson_fs correlation test, PRI and [(1/rRedEdge)-(1/rNIR)] were considered to be most useful index for the estimations of seasonal changes in Pn and LUE, respectively.
DE: 1851 Plant ecology
DE: 1640 Remote sensing
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting