U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Moderate Forest Disturbance as a Stringent Test for Gap and Big-Leaf Models
Published: January 27, 2015
Posted: November 03, 2015

Disturbance-induced tree mortality is a key factor regulating the carbon balance of a forest, but tree mortality and its subsequent effects are poorly represented processes in terrestrial ecosystem models. Thus unclear is whether models can robustly simulate moderate (noncatastrophic) disturbances, which tend to increase biological and structural complexity and are increasingly common in aging U.S. forests. Researchers recently tested whether three forest ecosystem models—Biome-BGC (BioGeochemical Cycles), a classic big-leaf model, and the ZELIG and ED (Ecosystem Demography) gap-oriented models—could reproduce the resilience to moderate disturbance observed in an experimentally manipulated forest (Forest Accelerated Succession Experiment in northern Michigan, where 38% of canopy dominants were stem girdled and compared to control plots). Each model was parameterized, spun up, and disturbed following similar protocols and run for 5 years post-disturbance. The models replicated observed declines in aboveground biomass well. Biome-BGC captured the timing and rebound of observed leaf area index (LAI), while ZELIG and ED correctly estimated the magnitude of LAI decline. None of the models fully captured the observed post-disturbance carbon fluxes, in particular gross primary production or net primary production (NPP). Biome-BGC NPP was correctly resilient but for the wrong reasons, and could not match the absolute observational values. ZELIG and ED, in contrast, exhibited large, unobserved drops in NPP and net ecosystem production. The biological mechanisms proposed to explain the observed rapid resilience of the carbon cycle typically are not incorporated by these or other models. Thus, an open question is whether most ecosystem models will simulate correctly the gradual and less extensive tree mortality characteristic of moderate disturbances.

Reference: Bond-Lamberty, B., J. P. Fisk, J. A. Holm, V. Bailey, G. Bohrer, and C. M. Gough. 2015. “Moderate Forest Disturbance as a Stringent Test for Gap and Big-Leaf Models,” Biogeosciences 12(2), 513–26. DOI: 10.5194/bg-12-513-2015. (Reference link)

Contact: Jared DeForest, SC-23, (301) 903-3251, Daniel Stover, SC-23.1, (301) 903-0289
Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling
  • Research Area: Terrestrial Ecosystem Science
  • Research Area: Carbon Cycle, Nutrient Cycling

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)