Mapping Quaking Aspen (Populus tremuloides Michx.) Using Seasonal Sentinel-1 and Sentinel-2 Composite Imagery across the Southern Rockies, USA

• DOI: 10.20944/preprints202404.0606.v1
• Publication Date: 2024-04-10T09:22:36Z
• Authors: Maxwell Cook; Teresa Chapman; Sarah Hart; Asha Paudel; Jennifer Balch

Quaking aspen (Populus tremuloides Michx.) is an important deciduous species in western U.S. forests. Existing maps of distribution are based on Landsat imagery and often miss small stands (<0.09 ha or 30 m²), which rapidly regrow when managed following disturbance. In this study, we present methods for deriving a new regional map forests using one year Sentinel-1 (S1) Sentinel-2 (S2) Google Earth Engine. We assessed the annual phenology Southern Rockies leveraged frequent temporal resolution S1 S2 to create ecologically relevant seasonal composites. Additionally, derived spectral indices radar textural features targeting canopy structure, moisture, chlorophyll content. Using spatial block cross-validation Random Forests, accuracy different scenarios selected best performing set classification. Comparisons were then made with existing landcover products across study region. The resulting improves both (average F1-score = 93.1%) detection smaller forest patches. These enable accurate mapping at scales management most widely distributed tree North America.