Throughfall Displacement Experiment

Project Description
The Throughfall Displacement Experiment (TDE)involves
developing models of global climate change to predict
increasing levels of greenhouse gases in the atmosphere.

Determined effect will be:

1. an increase in average global temperatures

2. alter regional levels of precipitation

3. increased levels of drought

The experiment:

Experimental manipulation of hydrologic inputs at the TDE is
accomplished by intercepting throughfall in approximately 2000
subcanopy troughs (0.3 x 5 m) suspended above the forest floor
on a "dry" treatment plot and transferring the throughfall
across a control plot for distribution onto a "wet" treatment
plot. Each plot is 80 x 80 m in size. The treatments result in a
33% decrease in precipitation reaching the forest floor on the
dry plot and a corresponding increase in precipitation on the
wet plot. Reductions in soil moisture on the dry plot are
expected to be equivalent to the driest growing seasons of the
1980's drought which resulted in reduced tree growth of some

The Throughfall Displacement Experiment is supported by the
Program for Ecosystem Research (PER) in the DOE Office of
Science, Office of Biological and Environmental Research (BER).

Contact Information:

Paul J. Hanson
Walker Branch Project Coordinator
Environmental Sciences Division
Oak Ridge National Laboratory
P.O. Box 2008, Building 1059
Oak Ridge, TN 37831-6422 USA

Visit the TDE website at

[Summary provided by ORNL]