Grantee Research Project Results
Influence of Elevated Nitrogen Deposition on Rocky Mountain Englemann Spruce Forest Nitrogen Cycling
EPA Grant Number: U915431Title: Influence of Elevated Nitrogen Deposition on Rocky Mountain Englemann Spruce Forest Nitrogen Cycling
Investigators: Rueth, Heather
Institution: Colorado State University
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 1998 through January 1, 2001
Project Amount: $76,061
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Fellowship - Ecology , Ecological Indicators/Assessment/Restoration , Academic Fellowships
Objective:
The objective of this research project is to determine whether Englemann spruce forests closer to urban and agricultural emission sources have higher nitrogen (N) concentrations and more rapid N cycling than those farther away.
Approach:
Six old-growth Englemann spruce stands east of the Continental Divide were compared with seven similar stands west of the Continental Divide. Our assumption that eastern sites receive greater N deposition than western sites is supported by National Atmospheric Deposition Program measurements for Colorado. All sites faced northeast, between 3,000-3,500 m, and had similar land-use histories and understory vegetation. The following hypotheses were tested. East slope sites have: (1) increased NO3 leaching; (2) increased foliar N, N:Mg, N:Ca, and del 15N; (3) decreased foliar lignin and lignin:N; (4) altered soil mineralization and nitrification rates; and (5) decreased soil organic matter C:N and base cations. A yearly N leaching loss index was determined using ion-exchange resin bags. Foliage and soil samples were analyzed for percent C and N, del 15N, major base cations, P, lignin, and cellulose. Soil texture, pH, and percent organic matter were measured to determine whether large site differences existed that could alter N dynamics.
Supplemental Keywords:
fellowship, nitrogen, N, Englemann spruce, National Atmospheric Deposition Program, foliar lignin, lignin, nitrogen cycling, land use, nitrogen deposition, urban emission sources, agricultural emission sources., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, ECOSYSTEMS, Ecological Indicators, Ecosystem Protection, Forestry, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecological Monitoring, Ecological Effects - Environmental Exposure & Risk, Ecology and Ecosystems, Environmental Monitoring, agriculture ecosystems, Rocky Mountains, agricultural environments, ecological assessment, nitrogen, Englemann Spruce, nitrogen cycling, agricultural emission sources, nitrogen depositionProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.