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Harvard Forest Symposium Abstract 2005

• Title: The Use of Waveform Lidar to Measure Temperate Mixed Deciduous Forest
• Primary Author: Jeanne Anderson (University of New Hampshire - Main Campus)
• Additional Authors: J.Bryan Blair (NASA Goddard Space Flight Center); Ralph Dubayah (University of Maryland); Michelle Hofton (University of Maryland); Peter Hyde (University of Maryland); Robert Knox (NASA Goddard Space Flight Center); Mary Martin (University of New Hampshire - Main Campus); Birgit Peterson (University of Maryland); Marie-Louise Smith (USDA Forest Service)
• Abstract:

  The direct retrieval of canopy height and the estimation of aboveground
  
  
  biomass are two important measures of forest structure that can be
  
  
  quantified by airborne laser scanning at landscape scales. These and other
  
  
  metrics are central to studies attempting to quantify global carbon cycles
  
  
  and to improve understanding of the spatial variation in forest structure
  
  
  evident within differing biomes. Waveform lidar imagery was acquired on
  
  
  September 26, 1999 and July 18-26, 2003 over the Bartlett Experimental
  
  
  Forest (BEF) in central New Hampshire (USA) using LVIS (Laser Vegetation
  
  
  Imaging Sensor), the airborne VCL (Vegetation Canopy Lidar) simulator. We
  
  
  found strong agreement between field and lidar measurements of height (LHT)
  
  
  and quadratic mean stem diameter (QMSD) with 1999 LVIS metrics (LHT: r2 =
  
  
  0.89, RMSE = 3.28 m., p < 0.000; QMSD: r2 = 0.88, RMSE = 3.41 cm., p <
  
  
  0.000) at the footprint level. Allometric calculations of aboveground
  
  
  biomass (AGBM) and basal area (BA) and 1999 LVIS metrics (AGBM: r2 = 0.76,
  
  
  RMSE = 54.75 Mg ha-1, p < 0.000; BA: r2 = 0.71, RMSE = 3.8 m2 ha -1, p <
  
  
  0.000) also showed good agreement at the footprint level. 1999 LVIS height
  
  
  metrics and resulting models did, however, show an overall tendency towards
  
  
  underestimation of actual height. Comparisons of Forest Service plot
  
  
  measurements of AGBM and QMSD from unmanaged forest tracts against
  
  
  predicted values based on 2003 LVIS metrics were within the range of error
  
  
  predicted by the models in 72% and 77.5% of the cases respectively. But
  
  
  direct plot-level relationships between Forest Service inventory plots and
  
  
  aggregated 2003 LVIS metrics were not as strong. Sampling limitations and
  
  
  variability in aggregated metrics weakened these relationships. Agreement
  
  
  improved when plot land-use history and species composition were factored
  
  
  into the analysis.

• Research Category: