Publications
Olympic National Park Consensus Determination of Eligibility: Sol Duc Road (ineligible)
A consensus determination of eligibility (cDOE) concluded that Sol Duc Road, located within Olympic National Park, is ineligible for listing on the National Register of Historic Places (NRHP). This decision, signed by the Acting Park Superintendent and supported by the Washington State Historic Preservation Office, evaluates whether the property meets NRHP criteria under Section 106 of the National Historic Preservation Act. The process involved a collaborative assessment by federal decision-makers, State Historic Preservation Officers (SHPOs), Federal Preservation Officers (FPOs), Tribal Historic Preservation Officers (THPOs), and other consulting parties. Additionally, two buildings (OLYM 1155 and 1156) and one site (Sol Duc RV Park) were evaluated and also deemed ineligible for NRHP listing.
Exploring spatial patterns of overflights at Olympic National Park
A study of Olympic National Park (OLYM) revealed distinct spatial patterns of overflights, with the highest density occurring between 0–500 ft above ground level (AGL), particularly along flight corridors and near Port Angeles. Using ADS-B data from three locations over 525 days, researchers identified seasonal variations in low-level flights below 10,500 ft MSL, noting a concentration of flights around Port Angeles at lower altitudes (0–6,000 ft). The analysis also mapped overflights by air tour operators, which largely adhered to recommended routes, and those intersecting with the Olympic Military Operations Area (MOA). These findings provide critical insights for park management and future research on aviation impacts in protected areas.
Elk monitoring in Mount Rainier and Olympic national parks: 2008 ‒ 2017 synthesis report
A decade-long study (2008–2017) reveals that elk populations in Mount Rainier National Park's North Rainier TCA increased at a mean annual rate of 3.9% despite seasonal and weather variability, while the South Rainier TCA showed no significant trend. Researchers developed refined aerial-bias-correction models using double-observer sightability trials (148 radio-collared and 1,653 non-radio groups) to adjust raw counts for detection biases tied to group size, vegetation density, lighting, and movement—improving accuracy across both parks. The study also identified shifts in elk distribution and population composition, with mean densities of 3.5 and 5.3 elk/km² in the North and South TCAs, respectively. These findings underscore the importance of standardized monitoring protocols for long-term wildlife conservation efforts.
Establishment and Survival of Subalpine Fir (Abies lasiocarpa) in Meadows of Olympic National Park, Washington
A 27-year study on subalpine fir (Abies lasiocarpa) establishment and survival in Olympic National Park's meadows reveals critical insights into climate change impacts. The research, conducted on south-facing tall sedge communities—unlike the more commonly studied north-facing heath-shrub types—found that sapling mortality was highest during early stages, stabilizing after a decade. Weather conditions, particularly high temperatures and drought, directly influenced seedling mortality during germination and establishment, while established sapling survival depended indirectly on weather via growth effects. Growth rates were enhanced by longer growing seasons and warmer minimum temperatures, with slow-growing saplings showing higher mortality risk. Most survivors thrived in lichen (Trapeliopsis granulosa) and Vaccinium deliciosum communities. The study highlights that while microsite conditions like snow depth matter, landscape position—such as north versus south aspect—plays a dominant role in determining meadow resilience to climate warming.
Geomorphology of coastal Olympic National Park
Olympic National Park's coastal region, surveyed from 2012 to 2016, reveals a dynamic and unique geomorphology shaped by the interplay of glaciation, tectonic activity, and coastal processes. The study identified 802 distinct landforms, including rare tombolos, numerous sea stacks, and 74 sand beaches, with glacial landforms such as moraines being the most extensive. Active tectonics and high wave energy have influenced this coastline, resulting in the absence of long barrier islands or deltas typically found elsewhere. The coast is divided into three distinct sections, each characterized by unique foreshore landforms associated with backshore and tectonic conditions. Glacial deposits are prevalent in the northernmost section, while the central section features intensely weathered bedrock prone to slumping, and the southern section dominates with long sandy beaches. Coastal bluffs, composed of 37% bedrock and 41% glacial drift, exhibit significant weathering and landslides due to wave undercutting and high rainfall. The study highlights the complex interaction of geological processes that have shaped this unique coastal landscape.
Olympic National Park vegetation classification and mapping project report
A comprehensive vegetation classification and mapping project for Olympic National Park reveals that coniferous forests, dominated by silver fir (Abies amabilis), cover four-fifths of the park, with upper montane and subalpine forests surrounding Mount Olympus. Wet lowland forests occupy 14% of the park, primarily on the west side, while drier lowland forests are found on the north and east sides. Broadleaf and mixed forests, shrub-dominated vegetation, and herbaceous vegetation each cover less than 5%. The study used an inductive modeling approach with random forests machine learning, incorporating data from plots collected between 2005 and 2019, satellite imagery, lidar data, elevation models, and climate normals. The resulting map includes 43 natural vegetated classes, seven mostly unvegetated natural classes, and four classes representing burned areas or anthropogenic disturbance.
Revised vegetation classification for Mount Rainier, North Cascades, and Olympic national parks: Project summary report
A comprehensive revised vegetation classification for Mount Rainier, North Cascades, and Olympic national parks has been developed, incorporating over 10 years of field data. This classification identifies 321 plant associations within 99 alliances, including 54 upland associations now part of the U.S. National Vegetation Classification (USNVC). The study used advanced statistical analyses to validate and refine vegetation types, revealing previously undescribed communities and revising or archiving others. The work builds on earlier research by Crawford et al. (2009) and integrates data from multiple sources, providing an up-to-date framework for understanding the ecological diversity of these UNESCO World Heritage Sites.
Effects of anthropogenic forest stresses on the distribution and abundance of the Olympic Torrent Salamander (Rhyacotriton olympicus) in the Olympic National Forest and Olympic National Park
A critical factor for the Olympic Torrent Salamander (Rhyacotriton olympicus) is stream gradient, with high-gradient reaches being essential for their occupancy. This finding comes from a study that surveyed 139 headwater stream reaches across 77 streams in Washington's Olympic National Forest and Park, using an information-theoretic approach to model selection. While the study identified significant predictors of salamander presence—such as gradient, turbidity, forest stage, and harvest distance—abundance analysis was limited by overdispersion, necessitating post hoc analyses. These revealed that fish presence, Tailed Frogs (Ascaphus truei), elevation, and stream flow also influence abundance. The research underscores the need for protecting high-gradient habitats and surrounding forests to manage salamander populations effectively.
Whitebark Pine in the National Parks of the Pacific States: An Assessment of Population Vulnerability
A comprehensive assessment of whitebark pine (Pinus albicaulis) populations across seven Pacific State national parks reveals significant vulnerability to non-native white pine blister rust and climate-driven mountain pine beetle outbreaks. The study, conducted by the National Park Service, found that blister rust infected 29 to 54% of trees in most parks, except for Sequoia & Kings Canyon and Yosemite, where infections were minimal (0.3% and 0.2%, respectively). Mortality rates due to beetle outbreaks ranged from 10 to 43% in the affected parks, with projections indicating a potential 25% population decline over the next century under worsening conditions. The research utilized a stochastic, size-structured population model based on Crater Lake data to forecast future trends, highlighting the urgent need for monitoring and conservation efforts to mitigate these threats.
Spontaneous and assisted restoration of vegetation on the bottom of a former water reservoir, the Elwha River, Olympic National Park, WA, U.S.A.
Spontaneous vegetation restoration on fine sediments of the drained Elwha River reservoir closely mirrors adjacent natural forests, suggesting rapid and effective ecological recovery without human intervention. This study found that substrate texture—fine versus coarse sediments—was the primary factor influencing plant community composition, with successional age and proximity to existing forests also playing significant roles. Assisted restoration techniques like planting or seeding showed no discernible benefit in accelerating native vegetation development on fine sediments. Invasive species were notably less abundant than anticipated, indicating a resilient recovery process. These findings highlight the potential for spontaneous succession in post-dam removal landscapes, particularly on finer substrates, while suggesting that active intervention may be necessary to enhance native plant communities on coarser sediments.
Adapting to climate change at Olympic National Forest and Olympic National Park
A collaborative climate change adaptation case study at Olympic National Forest (ONF) and Olympic National Park (ONP), spanning 1.5 years, demonstrated effective strategies for integrating climate resilience into federal land management. The study identified actionable adaptation options across four key focus areas—hydrology and roads, fish, vegetation, and wildlife—by combining science-based vulnerability assessments with stakeholder workshops. This approach highlighted the potential of place-based methods to mitigate climate impacts while providing a replicable model for other protected areas. Key insights include the feasibility of cross-agency collaboration in early-stage adaptation planning, offering scalable solutions for agencies managing diverse ecosystems.
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