Remote Sensing for Species Detection of Garry Oak Trees in the Urban Forests of Greater Victoria, British Columbia

Individual Garry oak trees are difficult to monitor, especially in urban areas that have many other planted and natural tree species mixed together. This study examined how accurately Garry oak crowns could be detected in the urban forests of Victoria and Saanich using high-density (45 points/m²) airborne laser scanning data versus a fused approach that combined airborne laser scanning with high-resolution (10cm) four-band orthophotography.

Individual tree crowns were first segmented from a canopy height model, and crown-level structural and spectral features were then extracted for classification. Two random forest models were compared: a LiDAR-only model with structural variables only and a fusion model that added spectral variables. The fusion approach produced more solid classification results than the LiDAR-only model.