PARENT SESSION
Poster Session #42: Carbon Storage.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Carbon balance in a high-elevation subalpine forest.

SPARKS, KIMBERLEE¹, SPARKS, JED¹, HARLEY, PETER², SCOTT DENTON, LAURA¹, TURNIPSEED, ANDREW¹, MONSON, RUSSELL¹, HUXMAN, TRAVIS¹, ^{1 2}

ABSTRACT- To examine the dynamics of carbon sequestration in a high-elevation forest ecosystem, we made measurements of carbon fluxes and pool sizes at the Niwot Ridge Ameriflux site. This forest is dominated by Pinus contorta, Abies lasiocarpa, and Picea engelmannii. Measurements of eddy covariance showed net ecosystem CO₂ exchange (NEE) reverses seasonally, acting as a net source during the winter and a sink through the growing season. These measurements estimated net carbon sequestration between 0.057-0.080 kg C m^-2 yr^-1 and cumulative respiration was estimated 0.60-0.70 kg C m^-2 yr^-1. Within-forest carbon fluxes and pool sizes were estimated using destructive harvests, soil measurements, carbon and nitrogen analysis, and litterfall collection. Standing aboveground carbon pools were estimated to be 11.4 kg C m^-2. Belowground pools were concidered to be the top 10 cm and estimated to be: 0.35 kg C m^-2 as litter and 5.0 kg C m^-2 as bulk soil, including 1.8 kg C m^-2 microbial biomass and fine root biomass as 1.6 kg m^-2. Major fluxes of carbon within the ecosystem were estimated as: 0.06 kg C m^-2 yr^-1 added as new growth to tree boles, 0.29 kg C m^-2 yr^-1 added as new growth to branches and needles, 0.11 kg C m^-2 yr^-1 transferred between trees and the soil as litterfall. These measurements will form the foundation of a carbon-dynamics model and used to validate future productivity and sequestration estimates.

KEY WORDS: carbon balance, eddy covariance, subalpine