Chapter 2: Summary of disturbances and sustainability
| Authors: | Tara M. Barrett, Christopher J. Fettig, Susan J. Frankel, Andrew Gray, I. Blakey Lockman, David W. Peterson, Guy Robertson, José J. Sánchez |
| Year: | 2021 |
| Type: | General Technical Report |
| Station: | Pacific Northwest Research Station |
| Source: | Chapter 2 In: Barrett, Tara M.; Robertson, Guy C., eds. 2021. Disturbance and sustainability in forests of the Western United States. Gen. Tech. Rep. PNW-GTR-992. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 11-19. |
Abstract
The 2010 “National Report on Sustainable Forests” (USDA FS 2011) identified forest disturbance as the most immediate threat to forest sustainability in the United States, based on increased levels of insect activity and fire activity relative to levels reported in the 2003 edition of that report. This concern, combined with the prominent role that western forests play in national statistics, was the motivating factor behind this report. Key questions for this project were, are forest disturbances increasing, and will they affect forest sustainability in the Western United States? A simple answer to these questions is “yes.” A more complete answer would be “yes, but in a complicated way.”
The answer is complicated because disturbances are part of forest ecosystems, and the complex web of interactions between species and their environment has been shaped over millennia by disturbance processes, and more recently by anthropogenic disturbances, including fire use in the pre-European settlement era and fire suppression over the past century (e.g., Hessburg and Agee 2003). It also is complicated because the values and uses that people ascribe to forests are diverse and sometimes contradictory. Social and economic effects of forest disturbances are not evenly distributed, and even disturbances that cause substantial tree mortality can bring some benefits along with costs. Finally, it is complicated because of the heterogeneous and highly variable nature of forest disturbances over time, being the sum of numerous different events and biophysical processes. That said, in this report we highlight recent disturbances that are having the most impact on western forests and the communities that depend on them. We also provide some baseline estimates of disturbance amounts and trends where data were available.