Quantifying Ground Vegetation within a Closed-canopy Forest: Sub-canopy Mapping with Unmanned Aerial Vehicle

Keywords: Unmanned Aerial Vehicle (UAV), sub-canopy mapping, supervised classification, overbrowsing, aerial imagery
Session Type: Virtual Poster
Day: Saturday
Session Start / End Time: 4/10/2021 03:05 PM (Pacific Time (US & Canada)) - 4/10/2021 04:20 PM (Pacific Time (US & Canada))
Room: Virtual 52

Abstract

The overabundance of white-tailed deer (Odocoileus virginianus) has resulted in devastating overbrowsing of forest plants. Assessing the ecological damage of white-tailed deer is time consuming and labor intensive. For our preliminary study, we utilized a small, highly maneuverable, Unmanned Aerial Vehicle (UAV) quadcopter to obtain sub-canopy aerial imagery for a supervised classification analysis. We compared understory vegetation in one open and one control deer exclosure plots in Monkton, Maryland. The analysis of the plots was accomplished through imagery collection in a documented UAV flight pattern. The images were converted into a composite using Adobe Photoshop and georeferenced for image analysis using ERSI ArcMap 10.6, followed by a supervised classification. The supervised classification is comparing pixels of vegetation versus non-vegetation. The results revealed that the exclosure plot contained 51% understory vegetation cover compared to 31% vegetation in the open control. Our findings highlight the large impact of deer on the understory plants and forest community. Because our UAV took images underneath the forest canopy and was able to avoid treelets, i.e., small trees and shrubs in the sub-canopy, it might be a more useful technique than acquiring imagery from the aircraft, satellite, or ground survey. In addition, our study suggests that a consumer level piece of technology can be used on projects with a smaller budget and with a demanding time constraint.