Ecosystem structure (DP3.30015.001)

Forests store and sequester a considerable proportion of the terrestrial global carbon budget. Forest canopy metrics are directly measurable with LiDAR sensors because laser pulses will be reflected from the uppermost canopy layers and remaining energy will penetrate to, and reflect from, under-story and the ground surface. The near simultaneous direct measurement of ground and canopy elevation allows the canopy height to be estimated through differencing. The CHM is generated by creating a continuous surface of canopy height estimates across the entire spatial domain of the LiDAR survey. The CHM is derived directly from the LiDAR point cloud. To produce the CHM, the point cloud is separated into classes representing the ground and vegetation returns. The ground classified points allow calculation of a height normalized point cloud to provide a relative estimate of vegetation elevation. A surface is then generated using the height normalized vegetation points to produce the CHM. For data collected with the Optech Gemini sensor (operated between 2012-2020), any canopy heights less than 2m are set to zero. NEON has been updating it's lidar sensors over the years, and data product quality has improved as technology has improved. For data collected with the Optech Galaxy Prime (2018+), Riegl Q780 (2021+), or Riegl VQ-780 II-S (2025+) sensors, any canopy heights less than 0.7 m are set to zero. Please refer to https://www.neonscience.org/data-collection/lidar for more details about NEON's lidar sensors and the derived data products.

Latency:
AOP data are expected to be available 60 days after the final collection day at a site.