Estimation of aboveground biomass and LAI of understory plant (Sasa senanensis) using a hand-held spectro-radiometer

Micro-environmental factors fluctuate seasonally and spatially under the canopy of deciduous broadleaved forest. A 6-band hand-held radiometer was applied to evaluate the effectiveness of spectro-radiometric method for estimating aboveground biomass (AB) and leaf area index (LAI) of understory plant (Sasa senanensis) at the Takayama experiment site in Gifu, central Japan. Measurement was limited in early spring season between snow melting and leaf development of forest canopy. The correlation and regression analyses using 45 sample dataset collected at neighboring site showed that the AB was linearly related to the Ratio Vegetation Index using 850 nm and 650 nm reflectance with R2=0.811, while LAI was exponentially related to the Normalized Difference Vegetation Index using 850 nm and 699 nm reflectance with R2=0.836. It was higher in correlation coefficient done by conventional destructive method. Distribution maps of AB and LAI of the one-ha experimental site were created applying these equations. Total AB and mean LAI of Sasa canopy in whole experiment site were estimated as 5.99±3.70 D.W. t ha-1, and 1.71±0.93, respectively. This research suggested that the possibility of radiometric method to obtain bio-information of heterogeneous natural vegetation easily and timely.