Yuba Headwaters Aspen Assessment and Planning
In 2020, the Wildlife Conservation Board (WCB) awarded SYRCL with a planning grant to conduct a watershed-wide aspen assessment. This effort cataloged the location, health, and size of aspen stands. In total, the assessment surveyed 123 aspen stands covering 490 acres on Tahoe National Forest (TNF) land within the Yuba River watershed. SYRCL’s aspen assessment paired on the ground stand evaluations with the development of a quantitative prioritization tool to select high priority aspen stands for restoration using geospatial data. The prioritization tool utilized three suitability models to perform a landscape level analysis: Access, Habitat Quality, and Stand Health. Of the 123 aspen stands surveyed, the Aspen Prioritization Tool identified Salmon and Packer Creek as the highest priority site and most suitable for aspen restoration. The aspen stands at Salmon and Packer Creek have a high potential for connectivity within the riparian zone, are at a high risk of stand loss due to conifer encroachment, have potential to be climate resilient due to their high elevation, and are easily accessible from a paved road.
Why Survey for Quaking Aspen?
Prior to the past thirty years, monitoring of aspen abundance and extent existed primarily as anecdotal evidence. The last aspen-specific surveys conducted in the Tahoe National Forest are over 20 years old, and some aspen stands had never been surveyed. Despite the sparse historical record and limited aspen survey coverage, it is widely accepted that aspen vegetation abundance within the watershed is in decline. SYRCL’s survey built on existing surveys by revisiting existing stands and identifying new stands in order to map the aspen stand’s size and to evaluate health and risk of loss. With these metrics, we can track the health of aspen stands and determine which aspen stands could be potential sites for future restoration projects.
Assessment and Survey
From 2020 to 2022 SYRCL staff conducted a field assessment of aspen stands within the Yuba River watershed as part of the Aspen Restoration Planning Project. This field assessment determined the location, health, and size of the aspen stands within a thirty minute walk from a vehicle. Previously mapped aspen stands from the USFS-led Aspen Delineation Project from the early 2000s and other sources were used to inform locations of existing aspen stands. The survey informed the extent and significance of aspen presence through quantitative field evaluation of stand structure, composition, causes of problematic conditions, and additional variables.
Prioritization Tool
Utilizing the watershed-wide assessment and survey data, SYRCL developed a quantitative decision-making restoration action tool in the form of a suitability model. The goals of the suitability model were as follows: 1) to identify the aspen stands at greatest risk of stand loss 2) locate the stands with the best habitat quality 3) identify the stands that are most accessible. The suitability model combines two important objectives: 1) which aspen stands are at greatest risk of stand loss and 2) which aspen stands are most important and feasible to restore. The suitability model streamlines this process by allowing the user to individually weigh the criteria.
Wildlife Cameras
As part of the monitoring efforts in aspen stands, wildlife cameras are placed throughout the watershed to assess the quantity and diversity of animal interactions in aspen stands. This data collection effort illustrates how important aspen are for the animals in our headwaters.
Next Steps: Restoration Project Identification
The output from the prioritization tool identified the aspen stands at Packer Creek and Salmon Creek as the most suitable for restoration based on the model’s criteria. With prioritization and site selection completed, the development of a restoration implementation plan is next. Restoration treatment types and prescriptions are selected based on site characteristics and management recommendations. The final goal of this watershed-wide planning project is to have a ‘Shovel Ready’ restoration project prepared for implementation.
Project Landmarks
Completed Watershed-Wide Assessment and Survey
Up Next
Created an Aspen Prioritization Tool
Planning for the Salmon and Packer Creek Aspen Restoration Project
Project Partners: US Forest Service, Tahoe National Forest
Project Funders: Wildlife Conservation Board
For more information, please contact:
Anne Marie Holt
Forest Conservation Project Manager
(530) 265-5961 ext. 216
annemarie@yubariver.org
