Accurate Mapping of Whitebark Pine and Disease in Western Washington National Parks

Project ID: P24AC01311

Federal Agency: National Park Service

Partner Institution: Portland State University

Fiscal Year: 2024

Initial Funding: $28,731

Total Funding: $28,731

Project Type: Research

National Park: Mount Rainier National Park

National Park: North Cascades National Park

National Park: Olympic National Park

Principal Investigator: Brunner, Ray

Principal Investigator: Gaines, Eleanor

Agreement Technical Representative: Fallon, Beth

2024 Year-End-Brief: P24AC01311_PSU_WhitebarkMapping_202412

2025 Year-End-Brief: P24AC01311_PSU_INR_WhitebarkMapping_202512

Abstract: 

Performance Goals – This project will fill a data gap critical to managing a threatened species, whitebark pine (WBP), by developing and evaluating methods to use remote sensing products to map WBP in North Cascades National Park Complex (NOCA), and Mount Rainier (MORA) and Olympic (OLYM) National Parks. The work will draw on existing tree spatial data, imagery, and lidar to characterize known WBP locations, differentiate those trees from co-occurring species, and extrapolate that analysis to build an accurate, high-resolution WBP map for our most understudied and disease impacted populations. The project will also pilot and evaluate methods to identify phenotypically disease-resistant trees using those same data, fast-tracking restoration and conservation planning. Mapping tree locations now is critical for the first steps in managing a threatened species, already experiencing high mortality from an invasive fungus, and now threatened by climate changes and potential shifts in fire regime.

WBP was listed as a threatened species (USFWS 2022, 87 FR 76882) under the Endangered Species Act, in 2023. In the three largest national parks in western Washington, NOCA, MORA, and OLYM, white pine blister rust, an invasive fungus, has killed 30-50% of trees within these large parks, with documented instances of complete mortality in some areas (Rochefort et al. 2018, Ward et al 2006) WBP is a near-treeline species especially important in high elevation Cascade ecosystems. These trees are important to hydrologic stability and new plant recruitment. Their seeds are fodder for wildlife, including Clark’s nutcrackers, who are also the primary WBP seed dispersers. WBP may be an important source of nutrition for red foxes and grizzly bear, another threatened species, that depend on WBP across its range, conservation of WBP may play an important role in grizzly bear recolonization of the North Cascades Ecosystem

Most WBP work to-date has been focused within denser stands in NOCA and MORA (Rochefort et al. 2012, Rochefort et al. 2018). Monitoring methodology has focused on high-density stands to meet statistical inferences thresholds (Rochefort et al. 2012). overlooking the broader and more sparsely distributed WBP populations within the parks OLYM was dropped from current monitoring efforts due to insufficient tree density (Ward et al 2006). However, the federal protections apply to individual trees rather than habitat. The average density of WBP even in core habitat is only 3-7% cover (NPS WBP Core Areas submission, 2020) The updated vegetation maps (2021) are an important resource for identifying WBP habitat, but 30% of WBP occurrences documented in the North Coast and Cascades Network Inventory and Monitoring databases do not fall within the boundaries of vegetation map classes with a WBP component Locating WBP stands has proved complicated and costly in the past 86% of potential monitoring sites were rejected during field visits for not containing WBP or enough WBP, even after office evaluations focused efforts on likely WBP habitat (NPS data). Some of our most unstudied known populations may be the most in need of conservation. OLYM hosts a genetically distinct and isolated population (Liu et al. 2016). Compliance processes following the WBP listing require an understanding of the impact on individual WBP trees in any given area.

Proposed conservation efforts are likewise focused on the individual tree: the primary method for stand conservation is based on identification and protection of rust-resistant individuals. Those individuals can be identified by phenotypic resistance to rust and, during a rare cone production year, seed collection to experimentally test for rust resistance. Resistance testing has been ongoing at MORA and NOCA but has been focused on the most accessible and studied populations. The process of identifying a rust-resistant tree may take more than 10 years and with tens of years more of growth needed to regrow sizeable sapling trees. Remote sensing methods of mapping could accelerate this process by identifying phenotypically healthy or diseased trees, thus narrowing the focus for where conservation efforts should occur (Haagsma et al, 2020).

This project will develop methods for high-resolution WBP mapping on a pixel basis within three parks: MORA. NOCA, OLYM WBP occur in open canopy woodlands and meadows, and mature WBP canopies are greater than 1 m’ in area. The tree canopy size means that imagery resolution of 1 m?, like the National Agricultural Imagery Program (NAIP) air photos that include a non-visible near infrared band, already processed for vegetation mapping in all parks, could be used to identify relatively small trees. The canopy shape of WBP is distinctive from other trees in the subalpine zone, and lidar data available for whole parks (MORA) or subsets of parks (OLYM, NOCA) may be used to distinguish tree physical forms. Additional multi-spectral remote sensing data may be available before the project begins, for example structure from motion high resolution orthophotography with an infrared band has just been collected at MORA. We will leverage work in NOCA and MORA that has built a database of WBP tree locations, disease status and resistance, as well as non-target species locations within monitoring plots. These data will be used to develop classification analyses (of species and disease status) based upon remote sensing data at each canopy center location. The project will build those discriminant analyses and develop an assessment of the statistical accuracy of the models based upon the extensive plot data in NOCA and MORA. Then we will extrapolate the best models to other areas of all three parks. The ground accuracy assessments (in-kind contributions) will focus on areas in which NPS will be in the field for other work. The eastern sections of OLYM would be a high priority area: this park has the least accurate information to inform management. Accuracy assessments or model refinement for the remaining populations will be done in-kind, coordinated with other park resource work, or incorporated into a second (now unfunded) phase of the work.