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Individual Highlight

If a Tree Falls in a Forest, How Long Does It Lie There

Photo of Mushroom on piece of downed dead wood. Fungal communities are a critical driver of dead wood residence times.  Christopher Woodall, USDA Forest ServiceMushroom on piece of downed dead wood. Fungal communities are a critical driver of dead wood residence times. Christopher Woodall, USDA Forest ServiceSnapshot : Dead wood is critical to nutrient cycling, carbon dynamics, tree regeneration, wildlife habitat, and wildfire behavior in forests. Forest Service scientists conducted one of the first large-scale studies of downed dead wood decay rates and found that the residence time of dead wood was dependent on the size of dead wood, its species, and climate in which it resides across forests of the eastern United States. Large pieces of dead conifer wood in high-latitude climates may reside for over 100 years in forests before completely decaying and disintegrating.

Principal Investigators(s) :
Woodall, Christopher W.  
Research Location : Eastern United States
Research Station : Northern Research Station (NRS)
Year : 2014
Highlight ID : 599

Summary

Downed and dead woody material (DWM) is created when trees fall or shed branches, and DWM is a substantial pool of carbon. The removal of DWM during harvests has raised questions about how long it would normally reside in forests. If DWM is determined to be a long-term store of carbon, then its conservation during harvests might be considered "carbon friendly." Forest Service scientists developed a technique for matching measured DWM pieces over short periods of time. Instead of waiting for DWM to decay (possibly a 100-year wait), a model was created to predict the probability of DWM moving from one stage of decay to the next. The decay model was applied to a DWM inventory across the eastern United States to estimate the residence time of DWM. For hardwood species, especially small DWM in warm andhumid climates, over half of the DWM biomass is lost to the atmosphere or other carbon pools within 10 years. For coniferous DWM in cold anddry climates, it may take over 100 years for carbon to be emitted or transferred to other pools. So, if a tree falls in a forest, how long does it lie there In eastern U.S. forests, the answer is between 30-100 years.

Forest Service Partners

External Partners

 
  • Matthew Russell and Anthony D'Amato (University of Minnesota)
  • Shawn Fraver (University of Maine)