Fremontodendron decumbens, Pine Hill flannelbush

Ilana L. Abrahamson; Leila Duchac; Taryn R. Brahmsteadt

Species Brief

Fremontodendron decumbens, Pine Hill flannelbush

Written

July, 2026

Contributors

Ilana L. Abrahamson - 1st Compiler, Leila Duchac - 1st Editor, Taryn R. Brahmsteadt - 2nd 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—Biological, ecological, and fire-related characteristics about Pine Hill flannelbush. Asterisks indicate areas of uncertainty or discrepancy. When asterisks are used, text in the justification field describes the uncertainty or discrepancy. This table is derived from a standardized template. The template includes all possible characteristics for each attribute.
Attribute	Characteristic	Justification	Source
Biological characteristics
Life form	Shrub	Pine Hill flannelbush is an evergreen shrub that is typically decumbent, growing up to 1.3 m tall and 5.5 m wide. More It branches from the base, and most of its branches are nearly horizontal making individuals much wider than tall.	FEIS: Botanical Description [1]
Typical lifespan	Insufficient information	The source does not provide explicit information about the typical lifespan of Pine Hill flannelbush. More It occurs on early successional sites and sites that have not burned in at least 50 years, but literature was lacking about how long it can persist on long-unburned sites.	FEIS: Successional Status [1]
Life cycle	Perennial	Pine Hill flannelbush is an evergreen shrub.	FEIS: Botanical Description [1]
Drought tolerance	High*	Pine Hill flannelbush predominantly occurs in xeric chaparral on south-facing slopes. Drought tolerance of mature plants is not described so it is inferred from its warm and dry habitat.	FEIS: Site Characteristics [1]
Rooting depth	Shallow*	Little information is available on Pine Hill flannelbush roots. One study found sprouts emerging from the shallow roots (<30 cm deep) of larger individuals growing within 1 to 2 m.	FEIS: Vegetative Reproduction and Regeneration [1]
Bark thickness at maturity	N/A	This attribute applies to trees.	FEIS: Botanical Description [1]
Sheds low branches	N/A	This attribute applies to trees.	FEIS: Botanical Description [1]
Reproduction and Regeneration
Adventitious buds	Root crown*; Root sprouts	Pine Hill flannelbush spreads vegetatively via root sprouts, and it resprouts from the stem base after top-kill or damage. Sprouts originating from the stem base are presumably from the root crown.	FEIS: Vegetative Reproduction and Regeneration; Immediate Fire Effects and Plant Response to Fire [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 persistent (>5 years)	Seeds that are not predated are long-lived under field conditions. One study found that more than 80% of Pine Hill flannelbush seeds survived after 5.75 years in the soil seed bank.	FEIS: Seed Banking [1]
Month(s) when seeds typically ripen	June; July; August; September	Capsules open from late June or early July until early August or mid-September, depending on the year.	FEIS: Seasonal Development [1]
Serotinous cones	N/A	This attribute applies to conifers. Pine Hill flannelbush produces dehiscent, ovoid-shaped capsules.	FEIS: Botanical Description [1]
Seed dispersal mechanism	Animal; Gravity	Pine Hill flannelbush seeds fall from capsules and are dispersed by ants. More The seeds have elaiosomes, fatty appendages that may be eaten by ants without harming the seeds, and harvester ants carry the seeds from beneath parent plants to their nests.	FEIS: Seed Dispersal [1]
Seed dispersal distance	Mostly under parent plant*; <100 m	Harvester ants carry elaiosome-bearing seeds from beneath parent plants to their nests. More Seeds on ant middens were often within 8 m of parent plants, and the farthest was 12 m. Seeds that are not carried off by ants likely remain under the parent plant.	FEIS: Seed Dispersal [1]
Optimal conditions for seedling establishment	Sun*	Little information is available about seedling establishment. More 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; Successional Status [1]
Successional Status
Shade tolerance	Shade intolerant*	The source does not provide explicit information about Pine Hill flannelbush shade tolerance. More Limited evidence suggests that establishment may be best on recently burned, open sites, and one author speculates that seedlings need sunny conditions.	FEIS: Seedling Establishment and Mortality; Successional Status [1]
Successional status	Early; Mid	Pine Hill flannelbush occurs on early successional sites and regenerates soon after fire. More It also occurs on sites that have not burned in at least 50 years, but literature was lacking about how long it can persist on long-unburned sites.	FEIS: Successional Status [1]
Fire
Primary fire response(s) or adaptation(s)	Recover/Resprout; Recruit	Pine Hill flannelbush is top-killed by fire but resprouts from its base (presumably the root crown) and from roots. More It also recruits from a long-lived, fire-cued soil seed bank, with seedlings establishing on burned sites.	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. More Upon dispersal, Pine Hill flannelbush seeds are dormant due to an impermeable seed coat, and 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 whether flowering or fruiting increases after fire.	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. More Fire effects were comparable after prescribed fires in June and October, with sprouting and seedling establishment after both.	FEIS: Immediate Fire Effects and Plant Response to Fire [1]
Plant flammability	Insufficient information	The source does not provide explicit information about the flammability of Pine Hill flannelbush. It typically contributes less than 5% of cover in chaparral dominated by other shrubs.	FEIS: Fuel Characteristics [1]
Early colonizer/recolonizer of burned or disturbed sites	Frequently*	Pine Hill flannelbush regenerates soon after fire by resprouting and by establishing from seeds on sites where it was present before fire, but little information is available. More One study found 145 seedlings on a burned site versus only 2 on an unburned site.	FEIS: Successional Status; Immediate Fire Effects and Plant Response to Fire [1]
Effect of fire exclusion on population	Decrease*	Because Pine Hill flannelbush reproduction is stimulated by fire, long fire-free intervals may reduce its populations, and in the absence of fire populations may decline over time. More Long-term effects of fire exclusion are considered a main threat, although it can also persist between fires by root sprouting.	FEIS: Fire Regimes; Fire Management Considerations [1]
Is this species typically managed with prescribed fire?	Sometimes	Prescribed fires have been conducted on Pine Hill, and fire promotes regeneration of the species. More The 2018 recovery plan includes managing habitat for fire and maintaining populations through two or more fire cycles.	FEIS: Immediate Fire Effects and Plant Response to Fire; Fire Management Considerations [1]
Predominant historical fire frequency 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	Typical fire cycles in the Pine Hill area may be about 30 to 50 years, and LANDFIRE models California Mesic Chaparral to have a roughly 54-year mean fire interval with 100% replacement-severity fire, consistent with fire regime group 4.	FEIS: Fire Regimes; 2020 LANDFIRE Biophysical Settings [1]
Alters historical fuel characteristics of ecosystems where it occurs	Rarely/No	Pine Hill flannelbush is not described as altering historical fuel characteristics in communities where it occurs. More It is a native shrub that typically contributes less than 5% cover in chaparral with high shrub canopy cover (i.e., 70%-80%).	FEIS: Fuel Characteristics [1]

2020 LANDFIRE Biophysical Settings — Historical Fire Regime Characteristics
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 October 14, 2026

Fremontodendron decumbens, Pine Hill flannelbush

Fremontodendron decumbens, Pine Hill flannelbush

Citation

Taxonomy and Nativity

Introduction

Biological, Ecological, and Fire Response Characteristics

LANDFIRE Biophysical Settings

References

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