%0 Research article
%T Calculation of wood volume and stem taper using terrestrial single-image close-range photogrammetry and contemporary software tools
%A Dean, Christopher
%D 2003
%J Silva Fennica
%V 37
%N 3
%R doi:10.14214/sf.495
%U https://silvafennica.fi/article/495
%X A method of estimating trunk and branch volumes of single trees is  presented that uses a combination of elementary field measurements,  terrestrial photography, image rectification and on-screen digitising  using commercial software packages and automated volume calculation. The  method is applicable to a variety of different sized trees in  situations where the trunks are clearly visible. Results for taper  measurement and wood volume calculation are presented for Eucalyptus  regnans F. von Muell., Sequoiadendron giganteum (Lindley) Buchholz and  Quercus robur L. Branch allometrics are provided for E. regnans. The  largest errors arose from field observations. If the trees are  asymmetrical in cross-section (e.g. due to irregular buttressing or  forked stems), or if there is no vantage point perpendicular to the  direction of lean, then photographs from more than one side are  recommended. Accuracy and precision of geometric reproduction by the  image rectification process, and the volume calculation, were tested  using mathematically generated tree components. The errors in the branch  volumes of the virtual tree showed complex trends due to interacting  factors. Volumes were underestimated by an average 0.5% for stems and 4%  for branches. Due to the area deficit resulting from non-circular  cross-sections of the buttress, overestimation of stem volumes could be  as high as 10% on average for mature trees. However, the area deficit  was known for E. regnans and incorporated into the volume calculation.   The underestimation of volumes would help counteract over-estimation due  to the area deficit. The application of this method to carbon  accounting in forests and woodlands is explained.