View dissertation.
This research focuses on refining methods for estimating belowground C and N, and estimating whole ecosystem C and N associated with woodland encroachment into sagebrush ecosystems, and the effects of land management, particularly prescribed fire, on ecosystem C and N. We found that our use of a soil coring device to estimate belowground biomass and C and N gives similar estimates to those obtained from quantitative soil pits. However, the core device is more efficient in regards to sampling time and data processing. It is noted that belowground biomass may exceed 1/3 of total biomass in transitional woodlands, and that soil contains more than 80 % ecosystem C and 90 % ecosystem N at low tree cover. As tree cover increases, biomass and C accumulates rapidly on the landscape, and closed canopy woodlands may exceed 60 % of ecosystem C in aboveground biomass, but less than 15 % N. Prescribed burning at low tree cover releases some C and N to the atmosphere, but a portion is incorporated into soil pools. Burning at increasing tree cover results in more C and N lost to the atmosphere and less C and N incorporated into soils.