研究目的
Investigating the combined use of ALS derived and digital aerial photogrammetry data along with intensive field measurements for extracting and predicting tree and stand parameters in even-aged mixed forests.
研究成果
The study demonstrated the potential of combining ALS and UAV data for forest inventory in mixed stands. Norway spruce trees were detected with higher accuracy than beech trees. The dbh and volume predictions were satisfactory for Norway spruce but less accurate for beech. Future research should focus on improving detection methods for beech trees.
研究不足
The study faced limitations in accurately detecting beech trees due to their rounded crown shapes and overlapping canopies. The OBIA classification had lower accuracy for distinguishing between beech and sycamore. Further investigations are needed for better individual tree detection methods for beech trees.
1:Experimental Design and Method Selection
The study used ALS data and UAV imagery combined with field measurements to extract tree and stand parameters. OBIA classification was performed to detect and separate main tree species, and a local filtering algorithm was applied to identify tree positions, heights, and crown diameters.
2:Sample Selection and Data Sources
Data were collected from four square plots of 1 ha each in mixed-species stands in South West Romania. Field measurements included tree positions, crown projections, vitality, competitive intensity, heights, and dbh.
3:List of Experimental Equipment and Materials
ALS data were collected using a Riegl LMS-Q780 laser scanner. UAV imagery was captured using a SenseFly eBee RTK drone equipped with a Canon S110 RGB camera. Field measurements were taken using Field Map equipment and a Vertex IV inclinometer.
4:Experimental Procedures and Operational Workflow
ALS data were processed to extract DTM, DSM, and CHM. OBIA classification was performed on UAV imagery to classify tree species. Individual trees were detected using a Canopy Maxima algorithm. Dbh was predicted using Monte Carlo simulations and linear regression models.
5:Data Analysis Methods
Data analysis included accuracy assessment of OBIA classification, individual tree detection rates, and statistical analysis of dbh and volume predictions using RMSE and relative RMSE.
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