Proceedings Article | 29 December 2008
Proc. SPIE. 7285, International Conference on Earth Observation Data Processing and Analysis (ICEODPA)
KEYWORDS: Carbon, Near infrared, Optical components, Optical sensors, Cameras, In situ metrology, Remote sensing, Photography, Photosynthesis, Direct methods
Leaf area index (LAI) is one of the most important parameters of canopy structure as it related to many biophysical and
physiological processes, including photosynthesis, respiration, transpiration, carbon cycling, rain intercepting, net
primary productivity, energy exchanging etc. Rapid, accurate and reliable estimations of LAI are required in these
studies above. There are two main categories of procedures to estimate LAI: direct and indirect methods. The objective
of this study is to evaluate LAI estimations obtained by different methods in HeiHe River forest sites. These methods
include the LAI-2000 plant canopy analyzer, HemiView, fifty-seven degree photography method, fisheye photography
method, the tracing radiation and architecture of canopies (TRAC), and Multi-Purpose Canopy Observation System
(MCOS). HemiView shows a large variation on gap fraction measurements compared to LAI-2000, fifty-seven degree
photography method is the superior choice to provide initial LAI values compared to other methods. To determine the
non-photosynthesis elements and foliage clumping effects for optical methods, a new device named MCOS (Multi-
Purpose Canopy Observation System) and TRAC were used. Finally, the results show that with the combination of
MCOS or TRAC and LAI-2000 or hemispherical photography can provide accurate and efficient LAI values.
