1. Canopy Structure Measurements with Ground-based High-Resolution Laser Range Sampling (LIDAR) Phil Radtke, Virginia Tech Britt Boucher, Foresters, Inc.

2. Why I’m Here
Affiliations with Bolstad & Martin re: canopy laser sampling
DOE SBIR/STTR project
Carbon sequestration measurements
Instrument availability/fieldwork
Love of dairy products

3. Why care about this? Canopy function related to structure
Direct measurements effort-intensive
E.g., litter collection, destructive sampling
Indirect measurements imperfect
Plumb lines
Optical methods
Light intensity inversion

4. Optical Methods
Measure LAI, PAI, gap-fraction, canopy-height profile, etc.
Lowest intercept point-quadrats (camera)
Aim telephoto camera lens straight up
Focus on lowest leaf/twig
Calculate height based on focal length
Repeat 10s – 100s of times
Elevate LAI sensor from pole, platform, crane etc.

5. Foliage Height Profiles

6. Difficulties Infinitely narrow “point” quadrat
Uniformly random foliage distribution in any canopy layer
Independence between layers
Sample-size bias
Depends on total n trials (e.g. 25 trials)
Maximum LAI = -ln(1/25) = 3.2

7. Laser Point Quadrats Infinitely narrow “point” quadrat
Uniformly random foliage distribution in any canopy layer
Independence between layers
Sample-size bias
Tissue type (branches, foliage, fruit)

8. Laser Point-Cloud Many range measurements from a single vantage point
Overcomes sample size limitation
Characterize heterogeneity/variability
Preserves X,Y,Z information of each interception
3D canopy modeling
Visualization
Spatially explicit estimators/summaries

10. Data format # ASCII Export File
# Automatically generated by - 3D-RiSCAN
# 3D data size - meas / line: 444
# lines / image: 1500
# meas id = meas# + line# * (meas/line)
# coordinates x y z [meter] a [1] r[m] pol[gon] azi[gon] id #

11. Data format
Range
Return Intensity

13. Data Acquisition

17. Summarizing the Data

18. Scan A
Scan B

19. Future Lab tests & validation trials Ecological studies
Algorithm development and modification
Corroborate with leaf litter, quantum sensors, etc.
Ecological studies
Scaling processes (LMA, light)
Biomass & Productivity
Tissue type (leaf vs. wood)
Multitemporal (inter and intra-annual)
Stress (catarpillars)
Diversity…
Teaching & Visualization