Carbon cycle dynamics within Oregon’s urban-suburban-forested-agricultural landscapes
- Oregon State Univ., Corvallis, OR (United States)
Our overarching goal was to develop and utilize an observation-based analysis framework to assess interactions between climate and mosaics of land use, land cover and urbanization on regional carbon, water, and energy dynamics, and potential changes associated with land management and climate. Carbon, water and energy cycling was quantified for the range of current and potential land uses under present and future climates. The study region of Oregon has a strong climatic gradient from the coastal mesic forests (2500mm ppt) to the Willamette Valley, Cascade Mountains, and the Northern Great Basin semi-arid “cold desert” to the east (300 mm). The study was focused on the effects of (1) conversion of semi-arid sagebrush and Willamette Valley agricultural crops to bioenergy production; (2) afforestation of idle land and rangelands deemed suitable for forests or poplar crops under future climate conditions. We found that net ecosystem production (NEP), the net of ecosystem photosynthesis and respiration, was 10 times higher in the high biomass forests of the Coast Range compared with drier regions like sagebrush in the Northern Great Basin, which was nearly zero (Schmidt et al. 2016). The state total NEP averaged about 30 teragrams carbon (Tg C) per year for the years 2012 to 2014 using our model framework that we developed for predictions of current and future NEP, and compared well with our detailed inventory estimates (28 Tg C annual average for 2011-2015 for forests only; Law et al. 2017). Running our model framework until the year 2050, we found that climate alone only increased NEP by less than 1 Tg C per decade (~3%) using the current trajectory of carbon dioxide emissions, however, changes are expected to be more rapid in subsequent years. We evaluated the possibility of land use change from grass seed crops to poplar for bioenergy, which slightly increased NEP by 2050. The most important variable for carbon sequestration estimates (net carbon sources and sinks) is net ecosystem carbon balance (NECB), which accounts for NEP and losses associated with harvest removals and wildfire emissions. Here, we focus on forests because they have the largest effect on carbon sequestration. We found that NECB in Oregon averaged 18.8 Tg C per year in 2011-2015, offsetting fossil fuel emissions (16 Tg C per year). Annual fire emissions reducing NECB by about 5% (0.97 Tg C per year) in the state. The mesic Coast Range and West Cascades ecoregions that make up the western third of Oregon account for 60% of the forest NECB. This analysis illustrates that annual emissions from forests disturbances are low relative to annual fossil fuel emissions for the same area (Law et al. 2017, Hudiburg et al. in review).
- Research Organization:
- Oregon State Univ., Corvallis, OR (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- DOE Contract Number:
- SC0012194
- OSTI ID:
- 1363940
- Report Number(s):
- DOE-OSU-12194-1
- Resource Relation:
- Related Information: Law, B.E., L.T. Berner. 2015. NACP TERRA-PNW: Forest Plant Traits, NPP, Biomass, Soil Properties, 1999-2014. ORNL DAAC, Oak Ridge, Tennessee, USA. http://dx.doi.org/10.3334/ORNLDAAC/1292. (dataset produced from our DOE projects and used in the analyses).Berner, L.T., and B.E. Law. 2016. Plant traits, productivity, biomass and soil properties from forest sites in the Pacific Northwest, 1999-2014. Nature Scientific Data 3:160002, doi: 10.1038/sdata.2016.2.Law, B.E., R.H. Waring. 2015. Carbon implications of current and future effects of drought, fire and management on Pacific Northwest forests. Forest Ecology and Management 355:4-14, dx.doi.org/10.1016/j.foreco.2014.11.023.Schmidt, A., B. Law, M. Göckede, C. Hanson, Z. Yang, and S. Conley. 2016. Bayesian optimization of the Community Land Model simulated biosphere-atmosphere exchange using CO2 observations from a dense tower network and aircraft campaigns over Oregon. Earth Interact. 20, 1-35, doi: http://dx.doi.org/10.1175/EI-D-16-0011.1.Law, B.E., T.W. Hudiburg, L. Berner, P. Buotte. 2017. Estimation of Oregon’s Current and Future Forest Sector Carbon Budget. White paper provide to Oregon Global Warming Commission (14 pp).Hudiburg, T.W., P. Buotte, A. Schmidt, L.T. Berner, B.E. Law. Carbon implications of changing forest management and land-use to meet bioenergy demands in Oregon, USA. Environmental Research Letters (In Review).
- Country of Publication:
- United States
- Language:
- English
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