A comparison of different methods for assessing leaf area index in four canopy types

Abstract

The agreement of Leaf Area Index (LAI) assessments from three indirect methods, i.e. the LAI–2200 Plant Canopy Analyzer, the SS1 SunScan Canopy Analysis System and Digital Hemispherical Photography (DHP) was evaluated for four canopy types, i.e. a short rotation coppice plantation (SRC) with poplar, a Scots pine stand, a Pedunculate oak stand and a maize field. In the SRC and in the maize field, the indirect measurements were compared with direct measurements (litter fall and harvesting). In the low LAI range (0 to 2) the discrepancies of the SS1 were partly explained by the inability to properly account for clumping and the uncertainty of the ellipsoidal leaf angle distribution parameter. The higher values for SS1 in the medium (2 to 6) to high (6 to 8) ranges might be explained by gap fraction saturation for LAI–2200 and DHP above certain values. Wood area index –understood as the woody light-blocking elements from the canopy with respect to diameter growth– accounted for overestimation by all indirect methods when compared to direct methods in the SRC. The inter-comparison of the three indirect methods in the four canopy types showed a general agreement for all methods in the medium LAI range (2 to 6). LAI–2200 and DHP revealed the best agreement among the indirect methods along the entire range of LAI (0 to 8) in all canopy types. SS1 showed some discrepancies with the LAI–2200 and DHP at low (0 to 2) and high ranges of LAI (6 to 8).

Impact of Superabsorbent Polymers and Variety on Yield, Quality and Physiological Parameters of the Sugar Beet (Beta vulgaris prov. Altissima Doell)

“…To objectively evaluate the growth of the sugar beet, especially in the initial vegetation phases, the leaf area index, which provides information on LAI and biomass production using photosynthetically active radiation (PAR), was chosen as the physiological parameter. Overall, LAI was measured six times (BBCH 18; 25; 31; 39; 46; 49) with SS1 SunScan Canopy Analysis System (Delta-T Devices Ltd., Cambridge, United Kingdom) as in [ 77 , 78 ].…”

Estimating Canopy Density Parameters Time-Series for Winter Wheat Using UAS Mounted LiDAR

“…Ground-based methods for the estimation of LAI include digital hemispherical photography (DHP) from cameras with fisheye lenses [3,11,12], ceptometry [13,14], or devices such as the LAI-2000/2200 plant canopy analyzer (LI-COR Biosciences, Lincoln, NE, USA) [3,[15][16][17]. These non-destructive methods rely on the gap fraction (GF) theory and radiation transmission.…”

“…Errors between 10% and 20% for forests and 10% and 15% for crops have been experienced when using LAI 2200 and DHP [3,[20][21][22][23][24]. Ceptometry methods, based on the measurement of average photosynthetically active radiation under a plant canopy using many individual light sensors, have shown underestimations in maize with a low-medium range of LAI [13]. However, others have demonstrated LAI estimates of sugarcane within 90% of what can be obtained with destructive measurements [25].…”

Biomass Allocation into Woody Parts and Foliage in Young Common Aspen (Populus tremula L.)—Trees and a Stand-Level Study in the Western Carpathians

“…The LAI of our aspen stands fluctuated between 2 m 2 m −2 and 14 m 2 m −2 . The maximum estimated value of nearly 14 m 2 m −2 is greater than the values published in most of the other papers covering a variety of forest tree species (often European beech) [46,47,[59][60][61][62][63]. The prevailing part of the other papers presented LAI values up to 10 m 2 m −2 .…”