Large scale mapping of forest attributes using heterogeneous sets of airborne laser scanning and National Forest Inventory data

Forest Ecosystems

Table 2 Summary of the ALS project characteristics

Number of ALS projects		367
Project area	Total (all projects)	17.0 Mha
	Mean	46,400 ha
	Min	941 ha
	Max	300,000 ha
Acquisition year	Range	2009–2019
Point density^a	Mean	3.5
	Min	0.2
	Max	10.0
Number of NFI field plots within an ALS project	Mean	25
	Min	1^b
	Max	186

^aNumber of laser echoes per m² as reported for each ALS project by the Norwegian Mapping Authority
^bALS projects containing at least one NFI field plot were included, predictions in ALS projects without any NFI plots were not analyzed in this study