MEASURING LEAF WATER CONTENT USING MULTISPECTRAL TERRESTRIAL LASER SCANNING
- 1Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
- 2Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, 02431 Masala, Finland
- 3Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
- 4Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute FGI, 02431 Masala, Finland
- 5Department of Built Environment, Aalto University, P.O. Box 15800, 00076 Aalto, Finland
Keywords: Tree health, drought, multispectral laser scanning, terrestrial laser scanning, forestry, leaf water content, Endoconidiophora polonica
Abstract. Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC) is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS). LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2) in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.