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Abstract:
Estimates of clumping index (Omega) are required to improve the indirect estimation of leaf area index (L) from optical field-based instruments such as digital hemispherical photography (DHP). A widely used method allows estimation of Omega from DHP using simple gap fraction averaging formulas (LX). This method is simple and effective but has the disadvantage of being sensitive to the spatial scale (i.e., the azimuth segment size in DHP) used for averaging and canopy density. In this study, we propose a new method to estimate Omega ( LXG) based on ordered weighted gap fraction averaging (OWA) formulas, which addresses the disadvantages of LX and also accounts for gap size distribution. The new method was tested in 11 broadleaved forest stands in Italy; Omega estimated from LXG was compared with other commonly used clumping correction methods (LX, CC, and CLX). Results showed that LXG yielded more accurate Omega estimates, which were also more correlated with the values obtained from the gap size distribution methods (CC and CLX) than Omega obtained from LX. Leaf area index estimates, adjusted by LXG, are only 5%-6% lower than direct measurements obtained from litter traps, while other commonly used clumping correction methods yielded more underestimation.
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CANADIAN JOURNAL OF FOREST RESEARCH
ISSN: 0045-5067
Year: 2019
Issue: 5
Volume: 49
Page: 471-479
1 . 8 1 2
JCR@2019
1 . 7 0 0
JCR@2023
ESI Discipline: PLANT & ANIMAL SCIENCE;
ESI HC Threshold:103
JCR Journal Grade:2
CAS Journal Grade:3
Cited Count:
WoS CC Cited Count: 13
SCOPUS Cited Count:
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 3
Affiliated Colleges: