Cowlitz River

Thick forest along the upper Cowlitz River illustrates the thick forest Lewis and Clark would encountered as they traveled down the Columbia River near the mouth of the Cowlitz.

Jeff Miller, Flickr, CC BY 2.0

Continuing down the Columbia River, past the mouth of the Cowlitz River, the expedition traveled through the Coastal Douglas-Fir Forest region. On November 6, 1805, Clark wrote in his journal that when they landed on the riverbank, the bushes and trees grew “So thick that our hunters Could not get through.”39

Climate change has caused increased tree stress and mortality in this region through multiple ecological disturbances. Severe drought magnifies the impacts of wildfire, disease, and insects such as bark beetles, resulting in unprecedented tree mortality. Scientists expect these disturbances to increase in the future, perhaps resulting in significant ecological changes to this forest.40

Citations:
39 William Clark, November 6, 1805 entry, in Gary E. Moulton, Journals of the Lewis and Clark Expedition, https://lewisandclarkjournals.unl.edu/item/lc.jrn.1805-11-06.
40 Jessica E. Halofsky, David L. Peterson, and Holly R. Prendeville, “Assessing Vulnerabilities and Adapting to Climate Change in Northwestern U.S. Forests,” Climatic Change 146, no. 1–2 (January 2018): 89–102, here 90, 94; Michelle C. Agne, et al., “Interactions of Predominant Insects and Diseases with Climate Change in Douglas-fir Forests of Western Oregon and Washington, U.S.A.,” Forest Ecology and Management 409 (February 1, 2018): 317–32, here 317.

Climate Change:Lewis and Clark Trail