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Citation:
USDA, Forest Service, Missoula Fire Sciences Laboratory. 2018. Fire regimes of quaking aspen communities of the Sierra Nevada and Southern Cascades: Information from the Pacific Southwest Research Station and LANDFIRE.
In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer).
Available: www.fs.usda.gov/database/feis/fire_regimes/CA_quaking_aspen/all.html
[].
The Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture, provides a review and synthesis of the historical range of variability for quaking aspen (Populus tremuloides) in the Sierra Nevada and Southern Cascades (Estes 2016 [2]). The review found that fire regimes of California's quaking aspen communities are not well researched, so information on fire regimes was based on only 6 studies. Quaking aspen communities or stands are typically interspersed within coniferous communities in the Sierra Nevada and Southern Cascades, and often small. They span a broad elevational range, from low-elevation vegetation zones to treeline, so fire-return intervals (FRI) are influenced by surrounding vegetation and range widely. Limited information suggests FRIs of quaking aspen communities interspersed with low-elevation mixed-conifer communities range from 30-90 years, and from 50-150 years for quaking aspen interspersed with California red fir (Abies magnifica) communities. One study found that across the Sierra Nevada and Southern Cascades, the mean FRI for quaking aspen communities ranged from 10-90 years (review by [2]). Quaking aspen stands require periodic stand-replacement fire to top-kill decadent growth and promote sprouting (review by [3]). Fire severity was historically of mixed and high severity in quaking aspen communities of the Sierra Nevada and Southern Cascades, with range of variation trending toward more high- than mixed-severity (i.e., mixed-replacement) fire. A study in the Great Basin found stand-replacement fire in quaking aspen stands occurred an average of 60 years, with mixed-severity fire occurring every 10-20 years (review by [2]).
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| Figure 1—Quaking aspen growing with Jeffrey pine (Pinus jeffreyi) and mountain big sagebrush (Artemisia tridentata subsp. vaseyana) in the eastern Sierra Nevada. Image used with permission of Gerald and Buff Corsi © California Academy of Sciences. |
Information is available from LANDFIRE succession modeling of quaking aspen Biophysical Settings (BpS) for the Sierra Nevada and the Southern Cascades. Table 1 summarizes LANDFIRE data on the BpSs in quaking aspen communities of the Sierra Nevada and Southern Cascade Range. Figure 2 shows where they occur. Table A1 lists the BpSs and the results of LANDFIRE succession modeling for each BpS in quaking aspen communities of the Sierra Nevada and Southern Cascades.
| Table 1. Modeled fire intervals and severities in quaking aspen communities of the Sierra Nevada and Southern Cascades [5]. | |||||||||
| Fire interval¹ | |||||||||
| Replacement | Mixed | Low | I | II | III | IV | V | NA³ | |
| 31-37 years | 24-46 | 15-54 | 0-61 | 1 | 0 | 2 | 0 | 0 | 0 |
| ¹Average historical fire-return interval
derived from LANDFIRE succession modeling (labeled "MFRI" in LANDFIRE). ²Percentage of fires in 3 fire severity classes, derived from LANDFIRE succession modeling. Replacement-severity fires cause >75% kill or top-kill of the upper canopy layer; mixed-severity fires cause 26%-75%; low-severity fires cause <26% [1,5] ³NA (not applicable) refers to BpS models that did not include fire in simulations. |
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| Figure 2—Land cover distribution of quaking aspen communities of the Sierra Nevada and Southern Cascades based on the LANDFIRE Biophysical Settings (BpS) data layer [5]. Numbers indicate LANDFIRE map zones. LANDFIRE did not map every BpS in this group. Click on the map for a larger image and zoom in to see details. |