NOTICE (July 2017): CDIAC will cease operations on September 30, 2017. Data will continue to be available through this portal until that time. A new DOE data archive is now at Lawrence Berkeley National Laboratory and is named ESS-DIVE. Data stored at CDIAC is being transitioned to ESS-DIVE and will be available from ESS-DIVE by September 30, 2017. If you have any questions regarding the new archive or the data transition, please contact

image image image image

FORAST Database

DOI: 10.3334/CDIAC/vrc.db1005

data Data


S. B. McLaughlin, D. J. Downing, T. J. Blasing, B. L. Jackson, D. J. Pack, D. N. Duvick, L. K. Mann, and T. W. Doyle


The Forest Responses to Anthropogenic Stress (FORAST) project was designed (1) to determine whether evidence of alterations of long-term growth patterns of several species of eastern forest trees was apparent in tree-ring chronologies from within the region and (2) to identify environmental variables that were temporally or spatially correlated with any observed changes. The project was supported principally by the U.S. Environmental Protection Agency (EPA) with additional support from the National Park Service.

The FORAST project was initiated in 1982 as exploratory research to document patterns of radial growth of forest trees during the previous 50 or more years within 15 states in the northeastern United States. Radial growth measurements from more than 7000 trees are provided along with data on a variety of measured and calculated indices of stand characteristics (basal area, density, and competitive indices); climate (temperature, precipitation, and drought); and anthropogenic pollutants (state and regional emissions of SO2 and NOx, ozone monitoring data, and frequency of atmospheric-stagnation episodes and atmospheric haze). These data were compiled into a single database to facilitate exploratory analysis of tree growth patterns and responses to local and regional environmental conditions.

The database files are divided into three groups. Two of the groups (FORASTR and FORAST) contain the same tree-ring chronology information (ring-width and basal area increments); one is sorted by region, and the other by tree species. The third group (FORASTEC) is a collection of miscellaneous background data including climate, air quality, and tree and site characteristics.

The database consists of 99 data files. The original 48 SAS data files are provided and require approximately 111 MB of disk space. In addition, CDIAC has created 48 ASCII files of the same data, an ASCII README file, region file, and species file. The region and species files merge all the files in the respective subdirectory. Hardcopy documentation describing the experimental protocols used and the format of the database files is available from CDIAC.

Portions of the FORAST database have been incorporated into the International Tree-Ring Data Base (ITRDB), a large collection of tree-ring data archived by and available from the National Geophysical Data Center (NGDC). For further information about the ITRDB, contact Bruce Bauer at NGDC (303-497-6280 or