Canadian Forest Service Publications
Stand canopy closure estimated by line sampling with airborne LIDAR. 2002. Magnussen, S.; Wulder, M.A.; Seemann, D. Pages 1-12 in K. von Gadow, J. Nagel, and J. Saborowski, editors. Continuous cover forestry – assessment, analysis, scenarios. Kluwer Academic Publishers, Dordrecht/Boston/London. 348 p.
Issued by: Pacific Forestry Centre
Catalog ID: 20507
Availability: PDF (request by e-mail)
Airborne scanning LIDAR with complete echo recovery and large (9 m) circular sampling areas (footprints) provides an opportunity for line sampling of stand canopy closure. With laser echoes differentiated into 'canopy' and near 'ground' hits the latter gives an estimate of the proportion of circular 9 m diameter 'holes' in the canopy. Sampling variance and confidence intervals of this estimate are based on a binomial model when canopy 'holes' are randomly distributed along the flight line, and on a spatial (cluster) resampling when canopy 'holes' are non-randomly distributed. The sampling distribution of canopy closure is thus either binomial or a mixture of binomials. Spatial clustering of canopy 'holes' was manifest in 11 of 33 flight lines examined. With about 700 observations per stand, sampling errors were below 1.7%.