Canopy structure indicators of forest developmental stage, disturbance, and certain ecosystem functions Geoffrey Parker, David Roy Fitzjarrald Smithsonian Environmental Research Center Edgewater, MD Atmospheric Sciences Research Center, UAlbany SUNY Albany, NY 12203

Normalized profiles of wind speed (dotted line), CO 2 (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 CO 2 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 LD HS first-return laser rangefinder 890 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 by MacArthur 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 height, 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