Vegetation height derivation from Shuttle Radar Topography Mission data in southeast Georgia, USA

A study was conducted to determine the extent to which data from the 2000 Shuttle Radar Topography Mission (SRTM) can be used to estimate vegetation canopy height in conjunction with an existing bald Earth DEM as provided by the National Elevation Dataset (NED). Intensively managed slash pine stands with canopy heights ranging from 11 to 21 m were biometrically surveyed within the general mission timeframe in early 2000. Results indicate that SRTM data can be successfully correlated via linear regression modeling with ground-measured mean vegetation canopy height at the stand level when mean SRTM-NED height difference measures are extracted by averaging pixels within the stands. Regression analysis using 20 and 50 pixels as stand size thresholds yielded adjusted r² values of 0.79 and 0.86 with rms errors of 1.1 m and 1.0 m respectively. Thus a minimum SRTM mapping unit of approximately 1.8 hectares can be postulated which allows vegetation canopy height retrieval at the stand scale