Forest Structure Measurements for GLAS Validation in Santarem 2004

Forest structure data from a 2004 GLAS satellite laser altimetry validation survey in Santarem and Sao Jorge, Para, Brazil. The dataset includes measurements from 11 primary forest sites and 10 secondary forest sites, covering tree dimensions, stem counts, and calculated biomass. It was produced by NASA researchers (Lefsky et al., 2005) to support the calibration of spaceborne forest canopy height estimates.

Use Cases

• Validating GLAS satellite laser altimetry estimates of canopy height using ground-measured total height and maximum height.
• Modeling aboveground biomass using calculated basal area and the Brown (1997) formula.
• Analyzing forest structure differences between primary and secondary sites using DBH, commercial height, and canopy width.
• Studying stem size class distribution in secondary forests using counts for stems 0-2cm, 2-5cm, 5 10cm, and >10cm.
• Relating canopy class descriptions to physical canopy measurements for ecological classification.

Strengths

• Provides ground truth data for 21 distinct forest sites (11 primary, 10 secondary) linked to specific GLAS satellite measurements.
• Includes calculated biomass and basal area using a published methodology (Brown, 1997 formula).
• Contains detailed, site-specific measurements like DBH, total height, commercial height, and canopy width.

Limitations

• Exact row count, file size, and complete column list are not provided by any source.
• Conflicting last updated dates exist between platforms (2004-11-18 on NASA Earthdata vs. 2026-03-13 on Data.gov).
• The license is ambiguously listed as 'other-license-specified' without explicit terms.

Provenance

Source

National Aeronautics and Space Administration (NASA), Lefsky et al., 2005.

Collection Method

Ground survey conducted along 75m transects per GLAS measurement site, measuring tree dimensions and stem counts.

Time Range

November 2004

Freshness

2026-03-13 01:11:25.663507

Geography

Santarem and Sao Jorge, Para, Brazil (Amazon region).