%0 Research article
%T Ground-based estimation of leaf area index and vertical distribution of leaf area density in a Betula ermanii forest
%A Sumida, Akihiro
%A Nakai, Taro
%A Yamada, Masahito
%A Ono, Kiyomi
%A Uemura, Shigeru
%A Hara, Toshihiko
%D 2009
%J Silva Fennica
%V 43
%N 5
%R doi:10.14214/sf.174
%U https://silvafennica.fi/article/174
%X We developed a ground-based method for estimating leaf area index (LAI)  and vertical distribution of leaf area density (LAD) for two Betula  ermanii plots, combining an allometric method for tree leaf area with  the MacArthur–Horn (MH) method using a portable laser rangefinder,  including a correction for changes in leaf inclination angle along the  vertical gradient measured with a portable digital protractor from a  canopy access tower in each plot. Vertical distribution of projected  leaf area density obtained by the MH method (LADMH) was transformed to  relative distribution for allotting fixed LAI to different heights.  Hence, we first developed an allometric method for estimating tree leaf  area for LAI determination. Trunk cross-sectional area at branching  height (AB) was accurately estimated (r<sup>2</sup> = 0.97) from  ground-based measurements of tree dimensions. We used this method to  apply pipe model allometry between tree leaf area and AB, and estimated  LAI (4.56 and 4.57 m<sup>2</sup> m<sup>–2</sup>). We then examined how  leaf inclination angle affected estimation of the vertical distribution  of actual LAD. Leaf inclination angle measurements revealed that actual  LAD in the upper canopy was 1.5–1.8-times higher than LADMH, because of  steep leaf inclination, while the correction factor was 1.15–1.25 in the  lower canopy. Due to the difference among heights, vertical  distribution of LAD estimated with correction for vertical change in  leaf inclination was more skewed to the upper canopy than that without  correction. We also showed that error in LAD distribution can result if  horizontal canopy heterogeneity is neglected when applying the MH  method.