A Comparison of Techniques for Measuring Canopy in Watercourse and Lake Protection Zones

We investigated seven methods for estimating overstory crown canopy. Subjective ocular estimates were compared with the more objective sampling tools; vertical sighting tubes and spherical densiometers. Intensive and controlled measurements allowed us to compare accuracy. We also present the time required to complete the different methods. Ocular estimates based on a walk-through of the riparian area proved sufficient for most pre-harvest evaluations. These estimates were always underestimates, which is conservative from a public trust resource perspective. Estimates that are more accurate require the use of a vertical sighting tube. We recommend the use of the vertical sighting tube to sample canopy along transects rather than plots, as the former are more efficient.