The role of woody detritus in biogeochemical cycles

A study site in the 200-year Log Decomposition Study at the Andrews Forest. 

A commentary by Mark Harmon, OSU professor emeritus, recently published in the journal Biogeochemistry focuses on the role of woody detritus (aka dead trees) in biogeochemical cycles.  The ecological role of dead trees in aquatic, terrestrial, and riparian environments has been a topic of long-held interest within the Andrews Forest community.  Moreover, the Andrews Forest hosts the so-called 200-year Log Decomposition Study.  One the study sites, affectionately known as the “log bone yard”, also serves as an observation station for the Long-Term Ecological Reflections program.  So, our collective obsession with the dead tree has been well established across disciplines.  

Harmon’s latest contribution examines the current state of knowledge regarding how dead trees have, and will, influence water, nutrient and organic matter flows within and between ecosystems to influence very small scale (the soil nutrients beneath a log) to global phenomena (the amount of carbon in the atmosphere).  Harmon’s commentary anticipates the key scientific developments needed to more fully understand how recently observed and projected increases in tree mortality will influence forested ecosystems function and management in the future.  He does this by not only reviewing the literature, but by developing a series of mini-models that synthesize knowledge to suggest hypotheses for future exploration.  Many of these explorations reveal that the response we perceive will be highly dependent on the level, or scale, of the examination.  For example, nutrients can be lost from a decomposing tree, but accumulate in a collection of the trees as forests age. This suggests that we need to not only learn much more about the processes controlling dead tree dynamics, but also must meet the challenge of building an integrated, multi-scale understanding. 

More reading:  

Harmon, Mark E. 2021. The role of woody detritus in biogeochemical cycles: past, present, and future. Biogeochemistry. 154(2): 349-369. doi: 10.1007/s10533-020-00751-x 

The LTER Reflections Program and the Forest Log, a collection of works of writers and artists in residence, including Jerry Martien’s Return of the Dead Log People, written after a visit to a 200-year log decomposition study site