SWOE Thermal Analysis and Measurement Program During the Forest Ecosystem Dynamics - Multisensor Aircraft Campaign

Forest Ecosystem Dynamics Multisensor Airborne Campaign (FED MAC): SWOE Thermal Analysis and Measurement Program (STAMP)

The Biospheric Sciences Branch (formerly Earth Resources Branch) within the Laboratory for Terrestrial Physics at NASA's Goddard Space Flight Center and associated University investigators are involved in
a research program entitled Forest Ecosystem Dynamics (FED) which is fundamentally concerned with vegetation change of forest ecosystems at local to regional spatial scales (100 to 10,000 meters) and temporal scales ranging from monthly to decadal periods (10 to 100 years). The nature and extent of the impacts of these changes, as well as the feedbacks to global climate, may be addressed through modeling the interactions of the vegetation, soil, and energy components of the boreal ecosystem.

Measurements of the temperature distribution within a bigtooth aspen were obtained to support development of a 3-D thermal model of trees. Measurements were taken in and around the tree trunk. Measurements were also taken of temperatures from one living and one dead branch. The tree trunk measurements were made at
three locations on the trunk at about 1, 5, and 8 feet above the ground.

At the one and five foot level, measurements were taken of the center and at different depths within the trunk. The in-depth temperatures were taken along lines corresponding to the compass directions. Four temperatures were taken at about one inch 1/4 inch from the bark outer surface. The latter depth was chosen to correspond to the approximate location of the inner surface of the bark. At the eight foot level, a probe was placed to measure the trunk center temperature.

The living branch was instrumented with four temperature probes. Two measured the branch center temperatures and two were placed under the bark at a depth of about 1/8 inch from the surface. The dead branch was instrumented with two probes. One was placed to measure the branch center temperature and the second about 1/8 inch from the surface. A series of probes were also placed to measure surface and soil temperatures around the tree. One was placed by the tree trunk and about three inches below the surface. Another probe was placed just below the surface in a clump of vegetation about six feet north of the tree. On 12 September 1990, the probes measuring the east and west trunk temperatures at the one inch in-depth locations were removed from the tree and relocated to measure the surface temperatures outside and inside the shadow zone of the tree.

Model 101 thermisters were used with two Campbell Scientific CR-21 data loggers to measure the trunk center and 1" depth temperatures. Type K chromel-alumel thermocouples were used with a Campbell Scientific CR-21X data logger to measure the under bark temperatures
on the trunk and branch temperatures.