Reflectance, leaf area index and structural studies of a rain forest canopy using the “Opération Canopée” association's tree top raft ‐ hot air airship combination

Abstract

To gain a better understanding of high variations observed in the spectral reflectance of rain forest canopies, an experiment was conducted in Campo, Cameroon to: 1. identify relationships between multispectral reflectance recorded at several altitudes and structural parameters such as the canopy roughness analyzed on the strength of aerial photographs, or the Leaf Area Index measured from the ground, 2. test at the same time the capabilities of an airship‐canopy raft combination in enhancing studies of the environmental heterogeneity of forest canopies.

Enabling simultaneous measurements above and below the vegetation, the tree top raft‐airship combination allows production of forest mosaic maps coupled with airborne radiometric and ground LAI measurements. Results emphasizes the importance of canopy structure studies whenever it is intended to derive a canopy parameter such as the Leaf Area Index from reflectance measurements. The raft‐airship set proved to be a tool highly suited to research involving forest functioning and remote sensing techniques.