Smithsonian Science News –Smithsonian Scientists Discover New c
Canopy structure indicators of forest developmental stage, disturbance, and certain ecosystem...
-
Upload
marilynn-hawkins -
Category
Documents
-
view
214 -
download
0
Transcript of Canopy structure indicators of forest developmental stage, disturbance, and certain ecosystem...
Canopy structure indicators of forest developmental stage, disturbance, and
certain ecosystem functions
Geoffrey Parker, David Roy Fitzjarrald
Smithsonian Environmental Research CenterEdgewater, MD 21037
Atmospheric Sciences Research Center, UAlbany SUNY
Albany, NY 12203
Normalized profiles of wind speed (dotted line), CO2 (solid line) and their product (i.e. the transport term) at the Old
Growth Site, LBA. (from Staebler, 2003).
Micrometeorological motivations: determining canopy mixing rates, displacement height, roughness length..….
U
CO2
Transport
Ecological objectives
• Introduce new metrics of canopy structure
• Examples of application at LBA sites
• Differences between treatments, sites
• Implications for radiation exchange
portable LIDAR for rapid determination of canopy structure
• Up-looking high-frequency rangefinder
• Deployed along transects at forest floor
• Estimates of volumetric surface area density with a spatial resolution 1-2 m
• Mean, variance, and spatial co-variation of several metrics
Lidar measurements (details):
Riegl LD90-3100HS first-return laser rangefinder890 nm; 1 kHz operation
Mounted to the front of a frame, 1 m above the ground.
Moving at walking speed through the forest, yields distances between measurements about 1 cm.
Spot size of the laser beam is 4-6 cm at the ranges encountered here.
Vertical profiles calculated using the overlap distribution described byMacArthur and Horn (1969).
Resolution as averaged for this study: 1 m in vertical, 2 m in horizontal.
Yields parallelepidep ‘voxels’ of 1X2X1 m in x,y,and z.
Desesperados……
Some derivable metrics
• Cover, estimates of canopy area index
• Maximum and average surface height
• Vertical distribution of surface area density
• Distribution of maximum heights
• Complexity of outer canopy surface
• Internal porosity
• Gap-size distribution
maximum height
horizontal distance, m
heig
ht,
m
the outer canopy hypsograph
• The cumulative distribution of top heights, specifically (LOCH, local outer canopy height)
• Not the same as the distribution of all surface areas
• Topographic analogy: elevations in a catchment basin
Outer canopy hypsograph in a chronosequence of eastern deciduous forests
LBA-ECO Santarem study area
km67 site— a pretty rough forest…
LBA-ECO Manaus Study area
Looks smooth from the air…..
Highly dissected terrain Manaus ‘ZF-2’ site
Some perspective from previous measurements…..
conclusions
• Canopy structure– similar within site, including logged and intact– differs between Tapajos and Manaus sites
• Canopy rugosity at Tapajos, landscape roughness at Manaus ZF2
• Differences in transmitance and absorption profiles, radiation-use efficiency
many thanks
Julio Tota, Cibelle Sampaio, Scott Saleska NASA: LBA-ECO CD-03
National Science Foundation NASA-Goddard, Global Canopy Program Atmospheric Sciences Research Center, SUNY Wind River Canopy Crane Research Facility, Smithsonian
Environmental Research Center