Background for The 200 Year Decomposition Site
by Mark Harmon
Dead trees have been part of forests for 300 million years, but only recently have scientists studied the various roles they play in forests. One key question is how long a dead tree “lives”; initial estimates indicated that for some species, such as Douglas-fir, it might be as long as the average live tree. However, aging dead trees after the fact is imprecise as is knowledge of how the dead tree began its life. Scientists at the H. J. Andrews proposed to study the log decomposition process as part of the US National Science Foundation’s Long-term Ecological Research Program (LTER). Given this process could take hundreds of years it was an ideal example of a long-term study. In 1985 the study was inaugurated, with logs of four species placed at six sites within the H. J. Andrews Experimental Forest. All the logs were documented as to their starting condition in terms of their initial volume, density, and mass as well as water and nutrient content. Periodically, a subset of logs is sampled to determine how these variables have changed over time. The study has expanded in recent years to be part of the Long-term Ecological Reflections program so that arts and humanities-related observations can be documented as well.
by Fred Swanson
Over its 40-year history, this 200-year log decomposition experiment has been a monument of commitment to long-term research in the world of ecosystem science. It’s an experiment established for the duration of the long-term phenomenon in question. And over the 20+ year history of the Long-Term Ecological Reflections program at Andrews Forest it has inspired visiting writers and artists, leading to an outpouring of fascinating works which cast new perspectives on the experiment itself. Then fires burned through several of plots in this experiment and also long-term vegetation plots and experimental watersheds, triggering new research questions, new roles for those in the humanities (e.g., helping us all deal with grief), and even a shift in views of the nature of the science we are doing as a community of inquiry several generations deep. The learning continues! This is vital in such challenging times.
Artist Statement
The 200 Year Long-Term Log Decomposition Site
by Ian van Coller
Installed in 1985, the Long-term Log Decomposition Site is an area of old-growth forest that is part of the HJ Andrews Experimental Forest in Oregon. Tree trunks of various species have been placed in patches of forest and then researched over a span of 200 years as they decompose. This site has and will provide information that elucidates how old growth forests act as nutrient and carbon sinks, which are essential to validate preservation efforts as the climate crises progresses at an exponential rate.
As part of my larger Naturalists of the Long Now project, these prints are direct collaborations with scientists and writers who conduct research at the experimental forest. Over a period of three years, (2021-2024) I photographed portions of the forest both before and after a significant portion of the forest burned. I asked my collaborators to reflect on the landscapes and then annotate directly onto the inkjet prints. Each annotated two prints, one of a photograph taken before the burn and the other after the burn.
This project breaks down barriers between art and science, and creates a dialogue between text and image, landscape and viewer, expert, and novice, past, present, and future. Through the exploration of earthly archives such as old growth forests, my intention is to encourage people to think in terms of longer spans of time and consider what humanity and nature will look like in 100 or even 10,000 years.
The Collaborators
Mark E. Harmon. Professor (Emeritus). Dept. of Forest Ecosystems and Society. Oregon State University. Forest carbon science. Founder of the Log Decomposition Experiment.
Kathleen Dean Moore. Distinguished Professor (Emerita). School of History, Philosophy, and Religion. Oregon State University. Philosophy/writing.
Frederick J. Swanson. Research Geologist (retired). US Forest Service, Pacific Northwest Research Station. Disturbance ecology.
Georgia Seyfried. Assistant Professor. Dept. of Forest Ecosystems and Society. Oregon State University. Belowground ecology.
Julia Jones. Distinguished Professor. Geography and Environmental Sciences. Oregon State University. Geography.
Mathew Betts. Professor. Dept. of Forest Ecosystems and Society. Oregon State University. Principal Investigator of the HJ Andrews Experimental Forest Long-Term Ecological Research Program.
Meg Krawchuk. Associate Professor. Dept. of Forest Ecosystems and Society. Oregon State University. Fire landscape ecology.
Mark Schulze. Director, HJ Andrews Experimental Forest. Dept. Forest Ecosystems and Society. Forest ecology.
Jacob Bukoski. Assistant Professor. Dept. Forest Ecosystems and Society. Oregon State University. Forest carbon science.
About The Photography Sites
by Fred Swanson
The photography in this project was done mainly at two of the six sites where Mark Harmon installed the Long-Term Log Decomposition Experiment in 1985 to begin an inquiry expected to last 200 years (Harmon 1992). He was a grad student then and recently hired. The project began with him leading a team of more senior scientists in compiling a tome summarizing what was known about dead wood in temperate forest ecosystems – a sort of knowledge milepost zero (Harmon et al 1986). This study has been part of the HJ Andrews Experimental Forest Long-Term Ecological Research (LTER) program funded by the US National Science Foundation (NSF) beginning in 1980.
The first photography in this project took place in site B3 (Harmon 1992) in early June 2023 and then again in Nov 8-10, 2024, which included some beautiful autumn colors. This site is the one most commonly visited by scientists, students, members of the public, and many others; and it has been a Long-Term Ecological Reflections plot visited by many of the 130+ artists and humanists in residencies managed by the Spring Creek Project for Ideas, Nature, and the Written Word since 2004. Site B3 has not been burned by the recent fires.
The 2023 Lookout Fire burned ca 70% of the Andrews Forest, including three of the six Log Decomposition Experiment sites, including site B6 near Cold Creek. Photography for this project in this site was done in Nov 8-10, 2024. Several other sites were also photographed at that time, including along the 1506 road looking south through burned forest, along the lower Old Growth Trail down to the log bridge, and in the 2024 Ore Creek Fire area just north of Andrews Forest.
Further Reading
Gaillard, Polly. Sept 23, 2025. Celebrating 20 years of Critical Mass: Preston Wadley (CM 2007) and Ian Van Coller (CM 2008). Lens/cratch: Fine Art Photography Daily.
Scientific American article about the experiment for general readership:
Ornes, Stephen. Sept 16, 2025. The secret lives of dead trees. Scientific American.
Newspaper article about the Log Decomposition Experiment:
Mapes, Lynda V. July 10, 2025. A Fire Charred This Forest. What Happens Next Dazzles. Seattle Times.
Short essay on deeper meanings of the experiment:
Pyle, Robert Michael. 2004. The long haul. Orion. September/October: 70-71.
https://andrewsforest.oregonstate.edu/sites/default/files/lter/pubs/pdf/pub3814.pdf
A poem giving voice to the logs:
Martien, Jerry. 2015. return of the dead log people. Pp. 205-206. In: Brodie, N., C. Goodrich, F.J. Swanson (eds.). Forest Under Story. U. of Washington Press.
State of scientific knowledge on wood decomposition at the start of the experiment. Google Scholar reports that this paper had been cited by over 5000 publications as of Sept 2025:
Harmon, M. E.; Franklin, J. F.; Swanson, F. J.; Sollins, P.; Gregory, S. V.; Lattin, J. D.; Anderson, N. H.; Cline, S. P.; Aumen, N. G.; Sedell, J. R.; Lienkaemper, G. W.; Cromack, K. Jr.; Cummins, K. W. 1986. Ecology of coarse woody debris in temperate ecosystems. In: MacFadyen, A.; Ford, E. D., eds. Advances in ecological research. Orlando, FL: Academic Press, Inc.: 15: 133-302.
https://andrewsforest.oregonstate.edu/sites/default/files/lter/pubs/pdf/pub42.pdf
Establishment report for the Log Decomposition Experiment with outline of the study scheme:
Harmon, Mark E. 1992. Long-term experiments on log decomposition at the H.J. Andrews Experimental Forest. Gen. Tech. Rep. PNW-280. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 28 p.
https://andrewsforest.oregonstate.edu/sites/default/files/lter/pubs/pdf/pub1045.pdf
Science publication reporting findings from the Log Decomposition Experiment:
Harmon, Mark E. 2021. The role of woody detritus in biogeochemical cycles: past, present, and future. Biogeochemistry. 154(2): 349-369.
https://andrewsforest.oregonstate.edu/sites/default/files/lter/pubs/pdf/pub5197.pdf