The Coweeta LTER site experienced a major drought during the past year. In 1986 precipitation totaled 124 cm, 57 cm below the average annual value. This is the driest year on record since establishment of the Laboratory in 1934 and probably is the driest year of this century. Much of the rainfall deficit occurred during the growing season, and, by autumn, hardwood mortality was apparent on ridges and other sites with shallow soils. In anticipation of the alteration of some ecosystem processes, research has been intensified to quantify drought effects. This research is being conducted with North inlet as a cooperative intersite effort arid is intended to supplement ongoing LTER activities at each site. The primary topics of intersite investigation include:
- Characterization of the drought event from a long-term climatic perspective
- Examination of water budget components
- Trends in precipitation and stream chemistry
- Organic sulfur formation/mobilization
- Modeling studies to complement the field studies
The drought provides a unique opportunity to quantify system responses to a major natural, low frequency hydrometeorological event.
Two new projects which utilize or supplement LTER data bases are in progress by Forest Service scientists at Coweeta. The 4-year integrated Forest Study on Effects of Atmospheric Deposition was started in 1985. The project involves 10 different localities or groups including Canada and Norway and 15 different forest ecosystems represented by both conifer and hardwood types. Coweeta is the only LTER site taking part in the project. The principal objective of the study is to evaluate the role of acid deposition in producing changes in forest nutrient cycling using a white pine plantation (WS 1) and a mixed hardwood forest (WS 2). The project is funded by the Electric Power Research Institute and administered through Oak Ridge National Laboratory.
The second project is the Direct/Delayed Response Project funded by the Environmental Protection Agency through its Corvallis Environmental Research Lab. Coweeta staff are collaborating with scientists from EPA, Tetra Tech, University. of Iowa, and University of Virginia in Level III analysis of this project.
The objective of these analyses is to utilize existing models of surface water acidification to classify watersheds in two target regions of the east in terms of their long-term (50-100 years) response to current and hypothesized levels of atmospheric deposition.
Stations for routine monitoring of ozone were established in April 1986 with current measurements being taken at three locations on north- and south-facing slopes within the Coweeta basin. The long-term goal is to develop a network of bioindicator plots within the basin to document gaseous pollutents in remote locations.
Dr. Andrew Williams from Plymouth Polytechnic Institute in England will be at Coweeta on a 3-month sabbatical beginning in April. His research will deal with hillslope hydrology and the quantification of water and solute movement through a soil profile.
The Coweeta symposium volume is in the hands of the publisher (Spring-Verlag) and should be published in 1987. The volume contains 30 chapters by 49 contributors and is organized into the following topical sections:
- Hydrology
- Geology
- Climate and water chemistry
- Forest dynamics and nutrient cycling
- Canopy arthropods and herbivory
- Forest floor processes
- Stream biota and nutrient dynamics
- Man and management of forested watersheds
- Perspectives on long- term research