||The projection of response of trees and forests to acidic deposition and associated pollutants /
Kiester, A. Ross. ;
Ford, E. D. ;
Avery, A. ;
Gay, C. ;
||NSI Technology Services Corp., Corvallis, OR. ;Forest Service, Washington, DC. ;Washington Univ., Seattle. Center for Quantitative Science.;Corvallis Environmental Research Lab., OR.
|| U.S. Environmental Protection Agency, Environmental Research Laboratory,
Forest trees ;
Plant physiology ;
Mathematical models ;
Quality assurance ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||222 pages : illustrations ; 28 cm
In 1986 the National Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern and trends of forest condition and physiological studies of seedlings, saplings, and branches of mature trees. The goals of the modeling effort were to simulate the dynamics of the processes by which acidic deposition and ozone affect tree physiological processes and therefore lead to changes in growth. Results from models of the physiological function of leaves, branches, roots, xylem, and canopies are presented here. These models illustrate three aspects of the dynamics of these processes. First, growth and the effects of pollutants are stochastic processes; that is, they vary randomly over time. The models help to account for the large amount of variability seen in normal field conditions. Second, some physiological processes can compensate for the effects of acidic deposition or ozone. Third, pollutants may have more than one effect on tree growth, and these effects may be synergistic. The potential nonlinearities and the variabilities demonstrated by these models lead to the conclusions that forest health effects may be developing that are not yet apparent; and for regulation of acidic deposition and associated pollutants to have a detectable effect, regulatory changes will probably have to be of substantial magnitude.