Mariposa Grove Boardwalk Storm Damage Reconstruction (2021 to 2022) - Yosemite National Park

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The Mariposa Grove Boardwalk, a one-mile interpretive trail winding through Yosemite’s Giant Sequoias, was severely damaged during the January 2021 Mono Wind Event. The storm toppled hundreds of trees—including twenty-one Giant Sequoias within the grove—causing significant structural damage to the boardwalk’s helical anchors, steel framing, and Alaskan Yellow Cedar decking.

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Treeline Construction Inc. was selected as the prime contractor to lead the demolition and reconstruction of the damaged segment. Our team developed and executed a rebuild plan tailored to the site’s highly sensitive setting, surrounded by mature Sequoias and spanning a delicate riparian corridor. Treeline self-performed all aspects of the work, beginning with the careful removal of bent and flattened steel components, including 9” and 12” I-beams, vertical posts, and hardware. All structural steel was re-fabricated to original specifications and reinstalled with precise alignment to the existing helical anchors. The Alaskan Yellow Cedar decking was removed, custom-milled to match the original tread pattern, and reinstalled using non-invasive methods to protect root systems and surrounding habitat.

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All work was completed under strict environmental protection measures, including low-impact access routes, tool containment protocols, and daily resource monitoring. Treeline managed quality control, safety, and project management in-house, allowing the team to adapt quickly to field conditions while minimizing the project footprint.

One of the project’s greatest challenges involved capturing accurate measurements and elevations of existing helical anchors embedded in soft riparian soils. Full anchor removal was deemed too disruptive to the habitat, requiring Treeline to adapt the new steel components to fit precisely within existing constraints. This careful, adaptive approach ensured structural integrity while preserving the site’s natural environment.

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The reconstructed boardwalk restored safe access for visitors to one of Yosemite’s most iconic landscapes and stands as an example of Treeline’s expertise in precision construction, preservation carpentry, and ecological sensitivity—balancing structural performance with environmental stewardship.