Relation between leaf area index and NDVI for subarctic deciduous vegetation

• Main Authors: Rees, WG, Golubeva, EI, Tutubalina, OV, Zimin, MV, Derkacheva, AA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Informa UK Limited 2020
• Subjects: 3709 Physical Geography and Environmental Geoscience; 37 Earth Sciences; 40 Engineering; 4013 Geomatic Engineering; 3706 Geophysics; Subarctic
• Online Access: https://www.repository.cam.ac.uk/handle/1810/306174; https://doi.org/10.17863/CAM.53254

We consider the relationship between leaf area index (LAI) and normalised difference vegetation index (NDVI) for green-leaf vegetation from a subarctic study site, specifically to test whether relationships optimised for lower-latitude vegetation can be assumed to hold at higher latitudes. We focus attention particularly on dwarf-shrub vegetation, which has received little previous investigation. We have collected hyperspectral measurements of the optical properties (reflectance and absorptance) of single leaves from dwarf shrub and tree species common to northern European Russia, and have developed a simple physical model of the properties of assemblages (‘leaf stacks’) of these leaves. The model is shown to provide a satisfactory explanation of the effect of varying the number of leaves in a stack on its NDVI, and can be easily adapted to make simple measurements using relatively inexpensive equipment. Our results show that the LAI-NDVI relationship for a vegetation canopy will saturate (approach within 10% of its limiting value) when the LAI reaches a value of around 2 to 3. Values this low are not uncommon in subarctic vegetation. It is also shown that dwarf shrub vegetation may show lower NDVI than trees for the same LAI. British Council Institutional Links Programme, grant 352397111 Ministry of Science and Higher Education of the Russian Federation, project RFMEF161618X0099