AGU 2014

With over 23,000 posters and presentations at the 2014 Fall Meeting of the American Geophysical Union, there was tons of interesting research to learn about.  Danelle Laflower and Shuang Liang gave posters in the session entitled Forests under a changing climate: uncertainties, carbon management, and adaptation.   

Danelle presented some findings from her investigation into the influence of projected changes in climate on carbon dynamics at Joint Base Lewis McChord in Washington.  Her work is part of the SERDP funded project to investigate the effects of forest management on carbon dynamics.

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Danelle used the LANDIS-II model and downscaled climate projections under a business-as-usual emission scenario and a moderate emission scenario to examine how fluxes of carbon would change over the 21st century.  She found that the moderate emission scenario and simulations run using climate data from the latter half of the 20th century produced similar carbon fluxes.  The study area remained a carbon sink throughout the simulation period and the decline over time was driven primarily by forest succession and maturation.  However, under the business-as-usual scenario, the amount of carbon taken up by the ecosystem declined much more rapidly, especially toward late-century.  This result was primarily driven by increased temperature and decreased precipitation during the summer months causing increased water demand by the trees and decreased water availability for growth.

Net Ecosystem Carbon Balance (NECB) captures carbon gains by the system from photosynthesis and carbon losses from the system from respiration and disturbance.  This figure shows the mean and standard error of NECB under the three different climate scenarios through late-century.

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Shuang presented some findings from her work on climate-fire interactions in the Sierra Nevada and how these two factors will cause species distributions to change over time.  Her work is part of the USDA funded project to investigate the effects of climate and wildfire on carbon dynamics and emissions.

Shuang also used the LANDIS-II model and downscaled climate projections under the business-as-usual scenario.  She simulated wildfire using recent distributions of wildfire size and frequency.  Two of the common, widely distributed species in the Sierra Nevada are ponderosa pine and white fir.  Ponderosa pine is more drought- and fire-tolerant than white fire.  She found that relative to simulations with late-19th century climate, the amount of ponderosa pine biomass increased under all three projected climate and wildfire scenarios, while the amount white fir biomass had a small initial increase and the fell below the baseline scenario.  This change is indicative of the area of the mountain range a range expansion for ponderosa and a range contraction for white fir.  The changes in distribution of the two species is a result of the combined effects of changing climate and wildfire.

These figures are percent change in biomass from the historical climate simulation.  The figure on the left is ponderosa pine and the figure on the right is white fir.

Both Shuang and Danelle are pushing forward on their projects, so stay tuned for more results as their research progresses.