Environmental Impact of Forest Management: Mica Creek Study Findings


07/08/2024


Forests are essential for capturing and filtering water, benefiting a multitude of organisms, including humans. In our activities such as planting, harvesting, and constructing roads, we implement thorough measures to minimize sedimentation and runoff to protect water quality and aquatic ecosystems.

We adhere to each state’s “best management practices” and our own guidelines, which have been refined through decades of research and science-based forestry. Following the 1972 Clean Water Act, many states introduced forest management guidelines to mitigate forestry's impact on water quality, though initial research on their effectiveness was sparse.
 
To address this, PotlatchDeltic initiated a groundbreaking study, the first of its kind among U.S. forest product companies, noted for its extensive duration, scope, and findings. In 1990, in collaboration with the U.S. Forest Service and the Idaho Department of Lands, we established the Mica Creek Experimental Watershed—spanning 6,672 acres southeast of Coeur d’Alene, Idaho. This "living laboratory" was created to conduct a multi-decade study on the impact of modern forest best management practices on stream water quality and aquatic life.
 
Throughout the study, we partnered with scientists from the University of Idaho and other academic institutions to gather data on the effects of tree harvesting, road construction, and other practices. The findings are published in independent, peer-reviewed journals such as Forest Science and presented at scientific conferences. As leaders on the Idaho Forest Practices Act Committee, we integrate the Mica Creek research findings into effective Forest Practices Act rules. The conclusions so far are promising, indicating that forest management following contemporary best practices has minimal to no negative impact on aquatic life in streams.
 
Key Findings of Mica Creek Research
Stream flows typically increase slightly after tree harvests. Stream temperatures in fish-bearing streams within harvested areas rise slightly in spring and decrease slightly in summer. Suspended sediment levels increase measurably in the first spring after thinning or harvesting but return quickly to pre-harvest levels. Forest management adhering to contemporary best practices does not harm fish, amphibians, or aquatic insect communities.
 
The results from the first 25 years of research, comparing treated and control stands, have been published in numerous scientific journals. In collaboration with the University of Idaho, we continue to gather data on water flow, sedimentation, fish populations, and other key environmental factors in the Mica Creek watershed. This area is now managed as a working forest, where we harvest, replant, and sustainably manage timber production. The ongoing research and monitoring provide continuous evaluation of the effectiveness of contemporary best management practices.