Characterisation of leaf area index and canopy light penetration of Hevea brasiliensis Muell. Arg by hemispherical photography
1982
Leong, W. | Yoon, P.K. (Institut Penyelidikan Getah Malaysia, Kuala Lumpur) | Lemeur, R.
Hemispherical photography was used to estimate leaf area index (LAI) and canopy light penetration of rubber trees. Three methods to decode the hemispherical pictures were evaluated. They were the electro-optical light intensity scanner, the computerised digitiser and the 'spider web' grid overlay. The three methods gave similar results. The electro-optical light intensity scanner was the preferred method as it was not subjected to inter and intra-observer errors, is less laborious and it takes the shortest time to decode a picture. Good correlation was obtained between LAI obtained from hemispherical pictures and LAI obtained from in situ leaf litter collection. The correlation between penetration of diffuse light obtained from hemispherical pictures and actual field measurements was very good. From these results it is suggested that hemispherical photography can be used to estimate LAI and canopy light penetration in a Hevea stand
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