Species Brief
Fremontodendron decumbens, Pine Hill flannelbush
Written
July, 2026
Contributors
Ilana L. Abrahamson - 1st Compiler, Leila Duchac - 1st Editor
Abrahamson, Ilana L., compiler. 2026. Species Brief: Fremontodendron decumbens, Pine Hill flannelbush. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-briefs/fredec
DOI
10.2737/feis-species-brief-fredec
Scientific Name
Fremontodendron decumbens
Common Names
Pine Hill flannelbush
FEIS Lifeform Type
Shrub
Kingdom
Plantae
Class
Magnoliopsida (Dicot)
Order
Malvales
Family
Malvaceae
Genus
Fremontodendron
Nativity
Native
Invasiveness
Noninvasive
This Species Brief is a concise summary of the biological, ecological, and fire‑related characteristics of an individual species derived from a Fire Effects Information System (FEIS) Species Review. Table 1 is derived from a standardized template and highlights these characteristics.
| Attribute | Characteristic | Justification | Source |
|---|---|---|---|
| Biological characteristics | |||
| Life form | Shrub | Pine Hill flannelbush is a decumbent evergreen shrub, growing up to 1.3 m tall and 5.5 m wide, branching from the base with nearly horizontal branches that make it much wider than tall. | FEIS: Botanical Description [1] |
| Typical lifespan | Insufficient information | The source does not provide explicit information about typical lifespan. | FEIS [1] |
| Life cycle | Perennial | Pine Hill flannelbush is an evergreen shrub. | FEIS: Botanical Description; Successional Status [1] |
| Drought tolerance | Insufficient information | Pine Hill flannelbush predominantly occurs in xeric chaparral communities on south-facing slopes. However, drought tolerance of mature plants is not described. Summer drought contributes to seedling mortality. | FEIS [1] |
| Rooting depth | Insufficient information | The source does not provide explicit information about rooting depth. | FEIS [1] |
| Bark thickness at maturity | N/A | This attribute applies to trees. | N/A |
| Sheds low branches | N/A | This attribute applies to trees. | N/A |
| Reproduction and Regeneration | |||
| Adventitious buds | Root sprouts; Root crown* | Pine Hill flannelbush spreads vegetatively via root sprouts and resprouts from the base of the dead crown (presumably the root crown) after top-kill from fire and from cut stumps. | FEIS: Vegetative Reproduction and Regeneration [1] |
| Time to reproductive maturity | 2-5 years* | No information was available on the age at which Pine Hill flannelbush produces seeds. However, one source states that an unspecified flannelbush species can produce seeds at 2 years old. | FEIS: Seed Production and Predation [1] |
| Soil seed bank longevity | Long-term persistence (>5 years) | Seeds that escape predation are long-lived under field conditions; one study found that more than 80% of seeds survived after 5.75 years in the soil seed bank. | FEIS: Seed Banking [1] |
| Serotinous cones | N/A | This attribute applies to conifers. Pine Hill flannelbush fruits are dehiscent capsules. | FEIS: Botanical Description; Seed Dispersal [1] |
| Seed dispersal mechanism | Animal; Gravity | Seeds fall from capsules and are dispersed by ants. Harvester ants carry the elaiosome-bearing seeds from beneath parent plants to nests located in gaps between shrub canopies. | FEIS: Seed Dispersal [1] |
| Seed dispersal distance | Short (mostly under parent plant) | One study found ant-dispersed seeds on middens were often within 8 m of parent plants, and the farthest seed found on a midden was 12 m from the nearest parent plant. | FEIS: Seed Dispersal [1] |
| Optimal conditions for seedling establishment | Sun* | Little information is available. One study found that on burned sites, seedling survival in gaps between shrubs is higher than under shrubs. The author speculates that seedlings under prefire Pine Hill flannelbush canopies are "doomed", perhaps because they need sunny conditions or they are outcompeted by sprouting plants. | FEIS: Seedling Establishment and Mortality [1] |
| Successional Status | |||
| Shade tolerance | Insufficient information | The source does not provide explicit information about Pine Hill flannelbush shade tolerance. Limited observations suggest seedling survival may be higher with sunny conditions. | FEIS: Entire; Seedling Establishment and Mortality [1] |
| Successional status | Early; Mid | Pine Hill flannelbush occurs on early successional sites and on sites unburned for at least 50 years, but how long it persists on long-unburned sites is undocumented, so its persistence into late stages is uncertain. | FEIS: Successional Status [1] |
| Fire | |||
| Primary fire response(s) or adaptation(s) | Recover/Resprout; Recruit | Plants are top-killed by fire but resprout from the roots and from the base of the dead crown. Fire also stimulates germination and seedling establishment from the soil seed bank. | FEIS: Immediate Fire Effects and Plant Response to Fire; Fire Adaptations [1] |
| Germination is fire stimulated | Often | Fire stimulates germination of seeds from the soil seed bank, with heat breaking the impermeable seed coat. Germination and emergence rates are very low until the seed coat is broken mechanically or by heat. One study found 145 seedlings on a burned site versus only 2 on an unburned site. | FEIS: Germination and Seedling Emergence; Immediate Fire Effects and Plant Response to Fire [1] |
| Flowering/fruiting is fire stimulated | Insufficient information | The source does not provide explicit information about fire-stimulated flowering or fruiting. | FEIS [1] |
| Season when it is most sensitive to fire | Insufficient Information | The source does not describe when Pine Hill flannelbush is most sensitive to fire and information about its response to fire is limited. Fire effects were comparable after prescribed fires in June and October, with sprouting and seedling establishment after both fires. | FEIS: Immediate Fire Effects and Plant Response to Fire |
| Plant flammability | Insufficient information | The source gives no direct measure of the plant's flammability. | FEIS: Fuel Characteristics [1] |
| Early colonizer/recolonizer of burned or disturbed sites | Frequently* | Little information is available. One study found Pine Hill flannelbush seedling establishment was much higher on a burned site than an unburned site, with 1,117 seedlings found over the burned area, and root sprouting was also stimulated by the fire. | FEIS: Immediate Fire Effects and Plant Response to Fire [1] |
| Effect of fire exclusion on population | Possible decrease | Because reproduction is stimulated by fire, long fire-free intervals may reduce populations, and in the absence of fire populations may decline over time. | FEIS: Fire Regimes; Fire Management Considerations [1] |
| Is this species typically managed with prescribed fire? | Sometimes* | Recovery criteria for this narrow endemic include conducting fire management studies, and the only documented fire effects came from a prescribed fire; routine prescribed-fire management is not described. | FEIS: Fire Management Considerations; Immediate Fire Effects and Plant Response to Fire [1] |
| Predominant historical fire frequencies of ecosystem where it most commonly occurs | Mid-frequency | Typical fire cycles in the Pine Hill area may be about 30 to 50 years. | FEIS: Fire Regimes [1] |
| Predominant historical fire severity where it most commonly occurs | Replacement | Pine Hill flannelbush occurs in California chaparral communities that typically have fire regimes characterized by stand-replacing crown fires. | FEIS: Fire Regimes [1] |
| Predominant historical fire regime group where it most commonly occurs | 4 | The species is most common in xeric chaparral, whose LANDFIRE Biophysical Setting (California Mesic Chaparral) is estimated to have a roughly 54-year mean fire interval with 100% replacement-severity fire, consistent with fire regime group 4. | FEIS: Fuel Characteristics; 2020 LANDFIRE Biophysical Settings [1] |
| Alters historical fuel characteristics of ecosystems where it occurs | Rarely/No | Pine Hill flannelbush is a minor component of its stands, typically contributing less than 5% of the cover on sites with 70%-80% shrub canopy cover, so it does not drive the fuel characteristics of its communities. | FEIS: Fuel Characteristics [1] |
| Biophysical Setting | Mean Fire Interval (years) | Fire Severity Percent (%) | ||||||
|---|---|---|---|---|---|---|---|---|
| Code | Fire Regime Group | Low | Mixed | Replacement | All | Low | Mixed | Replacement |
| Series 10970 - California Mesic Chaparral | ||||||||
| 10970_3_6_7 | IV-A | 54 | 54 | 0 | 0 | 100 | ||
| Series 10980 - California Montane Woodland and Chaparral | ||||||||
| 10980_6 | I-C | 54 | 92 | 34 | 0 | 63 | 37 | |
| Series 11140 - California Lower Montane Blue Oak-Foothill Pine Woodland and Savanna | ||||||||
| 11140_3_6_7 | I-B | 10 | 572 | 128 | 9 | 91 | 2 | 7 |
| Summary | ||||||||
| Minimum | 10 | 54 | 54 | 9 | 0 | 0 | 7 | |
| Maximum | 10 | 572 | 128 | 54 | 91 | 63 | 100 | |
| Mean | 10 | 313 | 91 | 32 | 30 | 22 | 48 | |
| Median | 10 | 313 | 92 | 34 | 0 | 2 | 37 | |
| Percentage 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%. | ||||||||
| LANDFIRE. 2020. Biophysical settings models and descriptions, [Online]. Washington, DC: U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; U.S. Geological Survey; Arlington, VA: The Nature Conservancy, (Producers). Available: https://www.landfirereview.org/search.php [96496] | ||||||||
1. Abrahamson, Ilana L. 2022. Fremontodendron decumbens, Pine Hill flannelbush. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/fredec
Last updated August 24, 2026