High-Resolution UAV Imagery and Ground Truth Tree Data of Deciduous Forests in Fruška gora National Park, Serbia

Study Area
The imagery covers a section of the Fruška Gora National Park in Serbia. More than 90% of the area is covered by deciduous forests at elevations above 300 m. The forest primarily comprises mixed stands with the following dominant species: Quercus petraea, Tilia spp., Carpinus betulus and Fagus sylvatica.
The park's highest peak is 539 meters above sea level. More than 80% of the forest is of coppice origin, and it is a managed forest. The imagery captures forest stands of varying ages, from very young to old-growth stands. Ground truth data focuses on stands more than 70 years old.

Data Collection Overview
1. RGB Imagery

• Equipment: High-resolution RGB images were captured using a Sony UMC-R10C camera mounted on a Quantum Systems Trinity F90+ UAV.
• Altitude: 134 meters.
• Ground Sampling Distance (GSD): 4.13 cm/pix.
• Coordinate System: Processed in EPSG:32634 (WGS 84 / UTM zone 34N).

2. Multispectral (MS) Imagery

• Equipment: Multispectral data captured with a Dual MicaSense Camera, covering 10 spectral bands spanning visible, red-edge, and near-infrared regions.
• Altitude: 135 meters.
• Ground Sampling Distance (GSD): 9.35 cm/pix.
• Coordinate System: Processed in EPSG:4326 (WGS 84).

3. Ground Truth Tree Data

• Sampling Methodology: Data was collected along transects representing monodominant or mixed forest stands, focusing on Quercus petraea, Fagus sylvatica, and Tilia spp.
• Tree Count: Approximately 120 trees were geolocated and measured.

Measurement Tools and Procedures:

• Geographic Coordinates: Recorded with a Garmin eTrex 20 GPS and manually corrected using RGB aerial imagery for improved precision.
• Tree Crowns: Delineated manually in QGIS 3.38.3 using RGB imagery.
• Tree Diameter: Measured at breast height (1.3m) using a diameter tape.
• Tree Height: Measured using a Haglöf EC II-D electronic clinometer.

Tree Attributes Recorded:

• Species latin name.
• Diameter at breast height (DBH).
• Tree height (H).
• Geographic coordinates (center of the tree crown).
• Elevation.

Temporal Coverage

• Field data collection occurred during autumn 2024.