Old Growth Ecosystems

We’ve all heard about old growth forests, but what are they, really? In our own research, reading academic articles, books, and visiting protected old growth forests in the United States and Europe, we have found there are many ways to define old growth forests. Criteria can include ecological, cultural, and historical factors; that’s why defining old growth forests can be so vexing and is much debated. 

Studies in the Pacific Northwest and Canada suggest that old growth ecosystems require at least 400 years of natural (unmanaged) aging to achieve high and stable biodiversity. The biodiversity curve from those studies is shown below.

For us at Boone Road, old growth is all about biodiversity.  Utilizing peer-reviewed academic studies we have identified characteristics of old growth ecosystems which promote high biodiversity.  Those key characteristics include: decomposing woody debris, (1, 2, 4, 5, 6) complex canopies and under-stories, (2, 5, 6) moist forest floors, (1, 2) high biomass, (2) thick humus, (5, 6) pits & mounds, (5, 6) and large tree sizes (6).  These characteristics become our objectives when using CTNF. In our research on old growth, we ask the question, "if our gentle CTNF harvests create characteristics more similar to old growth forests, can we increase biodiversity and accelerate a forest's transformation into a healthy old growth ecosystem?" We are optimistic that what may take an unmanaged forest 400 years to achieve, can be achieved in decades.

Citations:

1. Gresh and Courter 2021: Gresh, J.M., and J.R. Courter. 2021. In Pursuit of Ecological Forestry: Historical Barriers and Ecosystem Implications. Frontiers in Forests and Global Change 4: 571438.


2. Spies and Franklin 1988: Spies, T.A., and J.F. Franklin. 1988. Old Growth and Forest Dynamics in the Douglas-Fir Region of Western Oregon and Washington. Natural Areas Journal. 8(3): 190-201..


3. Falster et al. 2017: Falster, D.S., A. Brannstrom, M. Westoby, and U. Dieckmann. 2017.  Multitrait successional forest dynamics enable diverse competitive coexistence.  Proceedings of the National Academy of Sciences (PNAS). 1610206114.


4. Hansen et al. 1991: Hansen, A. J., T. A. Spies, F. J. Swanson, and J. L. Ohmann. 1991. “Conserving Biodiversity in Managed Forests.” BioScience 41, no. 6: 382–92.


5. Davis, M.B. 1996. Eastern Old-Growth Forests: Prospects for Rediscovery and Recovery. Island Press. Washington, DC.


6. Barton, A.M. and W.S. Keeton. 2018. Ecology and Recovery of Eastern Old-Growth Forests. Island Press. Washington, DC.