The BOREAS Information System

TE-6: Measurement and Scaling of Carbon Budgets for Contrasting Boreal Forest Sites

P.I.(s): Stith T. Gower -- University of Wisconsin
Co-I(s): John M. Norman -- University of Wisconsin

Objectives: To examine the influence of vegetation, climate and their interaction on the major carbon fluxes for aspen, jack pine and black spruce forest ecosystems at the Southern Study Area and Northern Study Area. Four, 15 x 15 m plots were established at each site during the fall 1993 IFC. We measured above- and below-ground net primary production and are using leaf respiration, autotrophic respiration and soil surface CO₂ flux data from other PI's to construct stand-level carbon budgets. Above-ground net primary production will be calculated annually for a 10-year period (1985-1994) from annual stemwood radial increment cores and site-specific allometric equations which will be developed in conjunction with M. Apps (TE-13). Below-ground net primary production will be estimated using sequential coring and carbon balance methods. Soil surface CO₂ flux will be measured weekly for the northern aspen stand during the IFC's using a LI-COR 6200 and soil respiration chamber. Soil surface CO₂ flux estimates obtained by this method will be compared to estimates obtained by PI's measuring soil surface CO₂ flux (using similar or different methods) at all mature forested sites at least once during 1994. We will develop a method to scale leaf-level photosynthesis measurements to the canopy level using measurements of canopy architecture and models of radiative transfer. The scaled canopy-level CO₂ fluxes will be compared to tower fluxes that are based on micrometeorological methods. We will develop and explore the utility of a new multi-band vegetation imager for indirectly determining forest canopy architecture in aspen and jack pine sites.

Deliverables to the Project

1. Carbon distribution in above and below-ground overstory and understory, forest floor and mineral soil for old aspen, jack pine and black spruce in SSA and NSA.
2. Annual net above- and below-ground net primary production and detritus production for overstory and understory for old aspen, jack pine and black spruce in SSA and NSA.
3. Soil surface CO₂ flux measurements for old aspen stand in NSA.
4. Archived plant tissue samples (stem wood, stem bark, branch, and foliage by age class and canopy position) for old aspen, jack pine and black spruce in SSA and NSA.

TE-6 Pictures

TE-6 does biomass and allometry readings at NSA-OA

TE-6 Data Sets