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The indicator measures the relative proportion of yellow pine forests in the Tahoe Region in less than mature seral stage stands. The relative abundance of small tree dominated stands is important because it provides a measure of forest sustainability; without young trees, Tahoe’s forests will not be sufficiently stocked to replace dead and dying trees over time. To produce spatial and structural heterogeneity in Tahoe's forest stands, the TRPA Code of Ordinances allows for the creation of forest openings of up to eight acres to achieve adopted management standards, and USDA Forest Service Lake Tahoe Basin Management Unit's Land Management Plan encourages the creation of openings of varying sizes and shapes that retain reserve trees and clumps.
A picture of a treated stand after the completion of the Montreal project around neighborhoods in South Lake Tahoe. (Photo courtesy of Amy Jirka, The Great Basin Institute)
Estimated percent cover of yellow pine forest, displayed in light red on the chart, as tree size-class <11 inches diameter at breast height. Data is from LTBMU EcObject, a forest-wide Region 5 Remote Sensing Lab vegetation data set that incorporates Light Detection and Ranging (LiDAR) into the mapping process. It is created from a multi-resolution segmentation of LiDAR-derived tree approximate objects and a 1-m canopy height model, which were then aggregated by stand and tree-level ecologic relationships.(USDA 2017)
Data provided by the USDA Forest Service, R5 Remote Sensing Lab. Access detailed datasets on Tahoe Open Data, including, vegetation type summary, vegetation spatial data, and detailed vegetation attributes.
- Status
- At or Somewhat Better Than Target
- Trend
- Little or No Change
- Confidence
- Moderate
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The yellow pine forest, which includes eastside pine, Jeffrey pine, Sierra mix conifer, lodgepole pine, and white fir, comprises 57 percent of the Tahoe Region, with 14 percent classified as immature.
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During the 2021 Caldor Fire, 4,536 acres of yellow pine forest—representing 2.6 percent of the total undisturbed vegetation—burned at moderate to high severity.
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A mortality event likely caused by a beetle outbreak adversely affected the white fir trees on the west shore of the Lake Tahoe Basin.
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Changes in forest composition occur over a longer time frame than the four-year cycle used for threshold evaluations.
Estimated proportion of land covered by different TRPA vegetation communities (associations) in the Lake Tahoe Region (USDA, 2010).
This indicator measures the relative proportion of tree stands classified in seral stages other than mature for yellow pine forests in the Lake Tahoe Region. For this evaluation, “seral stages other than mature” was equated with stands dominated by small diameter trees (less than 10.9-inches diameter at breast height). The relative abundance of small-tree dominated stands is important because it provides a measure of forest sustainability; without young trees, Tahoe’s forests will not be sufficiently stocked to replace dead and dying trees over time. Today, Tahoe’s forests are dominated by an intermediate age/size class ranging in diameter from 11 inches to 23 inches due to past Comstock-era logging and ongoing fire suppression (Raumann and Cablk, 2008b; Taylor, 2007). The area in the Region dominated by Jeffery pine forest has increased since 2003 (USFS LTBMU, 2015).
The primary natural driver in creating patches of small diameter trees in the Lake Tahoe Region is wildfire and other natural disturbances events. Recent forest management practices have focused on reduction of understory fuel loads in the wildland urban interface. Only now are basin agencies beginning to plan treatments for multi-values in the larger forest landscape that could contribute to standard attainment.
EIP Action Priorities
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Restore Native Vegetation and Forest Communities
The primary activities in this EIP action priority include reforestation and replanting after destructive fires to protect and restore native forest species.
EIP Indicators
- Acres of Forest Fuels Reduction Treatment
- Acres of Habitat Protected
- Acres of Habitat Restored or Enhanced
Monitoring Programs
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EcObject Forest Monitoring
Region 5 Remote Sensing Lab region wide vegetation mapping.
- At or Somewhat Better Than Target. Immature yellow pine forest currently comprises 24 percent of all yellow pine forests, which is within the target range of 15-25 percent.
- Little to no change. The 2021 Caldor Fire was the largest major disturbance impacting the vegetation communities in the Region during the evaluation period. The fire burned 4,536 acres of yellow pine forest in the region, 2.6 percent of all undisturbed vegetation, burned at moderate to high severity during the Caldor fire. There was also a documented die-off on White fir, especially on the west shore, likely attributed to a beetle outbreaks and drought-induced stress.
- High. Forest managers use best available technology and field reconnaissance to map and classify vegetation types throughout the Lake Tahoe Region about every five years; U.S. Forest Service vegetation mapping procedures meet regional and national vegetation mapping standards (FGDC, 1997; Warbington et al., 2011). Because vegetation communities are broadly defined and thus encompass larger spatial extents than individual habitat types, variation in the status and trend of the vegetation community richness indicator is not obvious at the relatively short time scales for which the indicator is remapped and reassessed.
- Moderate. There is moderate to high confidence that, in the absence of disturbance events (e.g., fires, disease, clearing), the spatial extent of vegetation communities at the regional scale does not change significantly over a four-year period. However, the recent Caldor Fire highlights that such disturbances can result in substantial shifts in vegetation dynamics, with approximately 4,536 acres of yellow pine forest likely lost from an estimated total of 97,504 acres.
- Moderate. If one confidence rating is high and the other is moderate, the overall confidence rating is the lower confidence rating.
No photos available.
No documents available.
April 2017. EcObject Vegetation Map v2.1 Product Guide. USDA Forest Service, R5 Remote Sensing Lab.