TY - JOUR
T1 - Variation of leaf angle distribution quantified by terrestrial LiDAR in natural European beech forest
AU - Liu, Jing
AU - Skidmore, Andrew K.
AU - Wang, Tiejun
AU - Zhu, Xi
AU - Premier, Joe
AU - Heurich, Marco
AU - Beudert, Burkhard
AU - Jones, Simon
PY - 2019/2
Y1 - 2019/2
N2 - Leaf inclination angle and leaf angle distribution (LAD) are important plant structural traits, influencing the flux of radiation, carbon and water. Although leaf angle distribution may vary spatially and temporally, its variation is often neglected in ecological models, due to difficulty in quantification.In this study, terrestrial LiDAR (TLS) was used to quantify the LAD variation in natural European beech (Fagus Sylvatica) forests. After extracting leaf points and reconstructing leaf surface, leaf inclination angle was calculated automatically. The mapping accuracy when discriminating between leaves and woody material was very high across all beech stands (overall accuracy = 87.59%). The calculation accuracy of leaf angles was evaluated using simulated point cloud and proved accurate generally (R2 = 0.88, p < 0.001; RMSE = 8.37°; nRMSE = 0.16). Then the mean (θmean), mode (θmode), and skewness of LAD were calculated to quantify LAD variation.Moderate variation of LAD was found in different successional status stands (θmean ∈ [36.91° 46.14°], θmode ∈ [17° 43°], skewness ∈ [0.07, 0.48]). Rather than the previously assumed spherical distribution or reported planophile distribution, here we find that LAD tended towards a uniform distribution in young and medium stands, and a planophile distribution in mature stands. A strong negative correlation was also found between plot θmean and plot median canopy height, making it possible to estimate plot specific LAD from canopy height data.Larger variation of LAD was found on different canopy layers (θmean ∈ [33.64° 52.97°], θmode ∈ [14° 64°], skewness ∈ [−0.30, 0.71]). Beech leaves grow more vertically in the top layer, while more obliquely or horizontally in the middle and bottom layer.LAD variation quantified by TLS can be used to improve leaf area index mapping and canopy photosynthesis modelling.
AB - Leaf inclination angle and leaf angle distribution (LAD) are important plant structural traits, influencing the flux of radiation, carbon and water. Although leaf angle distribution may vary spatially and temporally, its variation is often neglected in ecological models, due to difficulty in quantification.In this study, terrestrial LiDAR (TLS) was used to quantify the LAD variation in natural European beech (Fagus Sylvatica) forests. After extracting leaf points and reconstructing leaf surface, leaf inclination angle was calculated automatically. The mapping accuracy when discriminating between leaves and woody material was very high across all beech stands (overall accuracy = 87.59%). The calculation accuracy of leaf angles was evaluated using simulated point cloud and proved accurate generally (R2 = 0.88, p < 0.001; RMSE = 8.37°; nRMSE = 0.16). Then the mean (θmean), mode (θmode), and skewness of LAD were calculated to quantify LAD variation.Moderate variation of LAD was found in different successional status stands (θmean ∈ [36.91° 46.14°], θmode ∈ [17° 43°], skewness ∈ [0.07, 0.48]). Rather than the previously assumed spherical distribution or reported planophile distribution, here we find that LAD tended towards a uniform distribution in young and medium stands, and a planophile distribution in mature stands. A strong negative correlation was also found between plot θmean and plot median canopy height, making it possible to estimate plot specific LAD from canopy height data.Larger variation of LAD was found on different canopy layers (θmean ∈ [33.64° 52.97°], θmode ∈ [14° 64°], skewness ∈ [−0.30, 0.71]). Beech leaves grow more vertically in the top layer, while more obliquely or horizontally in the middle and bottom layer.LAD variation quantified by TLS can be used to improve leaf area index mapping and canopy photosynthesis modelling.
KW - Canopy structure
KW - European beech
KW - Leaf angle distribution
KW - Leaf inclination
KW - Leaf inclination distribution function
KW - Terrestrial laser scanning
KW - Variation
UR - http://www.scopus.com/inward/record.url?scp=85059848171&partnerID=8YFLogxK
U2 - 10.1016/j.isprsjprs.2019.01.005
DO - 10.1016/j.isprsjprs.2019.01.005
M3 - Article
AN - SCOPUS:85059848171
VL - 148
SP - 208
EP - 220
JO - ISPRS Journal of Photogrammetry and Remote Sensing
JF - ISPRS Journal of Photogrammetry and Remote Sensing
SN - 0924-2716
ER -