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Populus cites Time to extinguish on populus. On populus, green test condition beside populus on Populus. The facts answer different questions for populus — Populus. On populus, Time to extinguish does not replace green for populus.
Use evidence on populus for populus. Use test conditions on populus for populus. The sourced rows remain on populus. On populus, populus holds Time to extinguish beside green in the populus table for Populus.
Form
tree
Region
British Columbia, Canada; EE. UU.; Tasmania, Australia
Rated in
British Columbia; California; Cape Town, Western Cape, South Africa; Fremont County, Wyoming +11
On this lot
1. Fire evidence and conditions
Fire evidence
Fire-resistant — location does not change the cited classification.
British Columbia; California; Cape Town, Western Cape, South Africa; Fremont County, Wyoming; Global; Greece; Michigan / Great Lakes; Montana / Northern Rockies; Nevada / Great Basin; Oregon; South Carolina; Tasmania, Australia; Utah / Intermountain West; Yavapai County, Arizona; western WA
Maintenance
Typed publication scope: 9 scopes across 9 cited fire sources
Fremont County (WY footprint); partial normalized coverage · 2011-02-25
The source identifies itself as the Fremont County Firewise Plant List. FireApproved publishes its 92 exact source owners as Fremont County regional context. No methodology, current county endorsement, statewide Wyoming scope, or site-specific suitability is inferred.
King County's current wildfire page links this list for the Puget Sound Basin. FireApproved publishes 82 exact source owners as basin context, not statewide Washington guidance or a site-specific recommendation.
The UC Forest Products Laboratory says the guide covers properties of common California landscaping plants and was prepared for California fire agencies. FireApproved publishes 130 exact owners at historical California publication scope. The report is a 1997 compilation, not a current endorsement, site rating, or independent test of every row.
Michigan State University Extension Bulletin E2948 is explicitly a list of wildfire-resistant landscape plants for Michigan and includes a Michigan-native field. FireApproved publishes 221 exact GBIF owners from 226 represented source rows and holds 15 complex or non-exact rows. This dated publication scope is not a current site-suitability determination.
The April 2022 MontGuide explicitly presents fire-resistant species adapted to Montana. FireApproved publishes 92 exact plant records from the source while retaining excluded genus, family, and unresolved rows; the guide itself says not every listed species grows in every part of the state.
South Carolina Forestry Commission publishes this explicitly as its Fire Smart Plant List for South Carolina. FireApproved publishes 63 exact genus owners from 72 unique common-name labels; unsafe common-name mappings and duplicates are not broadened. The brochure calls the list non-inclusive and does not establish species-level or site-specific suitability.
University of Nevada Cooperative Extension compiled plants suited to Nevada climate zones and reported favorably by at least two upstream firewise lists. FireApproved publishes 126 exact source owners at Nevada publication scope. The source explicitly makes no independent flammability determination, so these rows remain corroborative.
Utah State University Extension states that this fact sheet selects examples for Utah landscapes and that they require proper placement and maintenance. FireApproved publishes 83 exact source owners at Utah publication scope. The table is not a site-specific planting clearance.
Yavapai County (AZ footprint); partial normalized coverage · 2025-03-14
University of Arizona Cooperative Extension authors Bulletin 34 for Yavapai County. FireApproved publishes 198 exact source owners from its resistant and prone tables and keeps the county boundary visible. County publication scope is regional Arizona context, never statewide scope.
2. Why this plant is relevant here
State distribution
Native range
Introduced / established
USDA hardiness
3. Legal, ecological, and broader status
Legal-list status
Seed-list status
Reported invasive here
Broader regional context
Federal context
How to read this page
The status above is computed from the cited rows below: independent recommendations can support a fire-resistant result, an avoid row can produce keep-away, and disagreement stays visible as conflict. Placement notes preserve each source’s own scheme rather than translating unlike rules into one scale. This is evidence about a plant, not permission to plant it in every part of the defensible space; Zone 0 remains noncombustible.
Conditions in the fire evidence
These describe tested or rated plant material. They are not horticultural maintenance instructions.
Placement rules below use each source's own distances or named zones, tied to its rating.
They are not interchangeable with the directory's current Zone 0 guidance.
Fire Resisting Garden Plants for the Urban Fringe and Rur…: remove from the Building Protection Zone; avoid in the Fuel Modified Zone [Texas Building Protection Zone] (with its avoid rating)
Fire-Resistant Plants for Oregon Home Landscapes: Oregon [osu-frn6-oregon-regions] (with its recommendation)
Time to extinguish the exotic flame: Lessons from the 202…: Urban zone; Table 1 and deposited raw workbook [macalister-2025-leaf-flammability] (mid-scale rating)
Defensible Space Landscaping in the Urban/Wildland Interf…: Chapter 4, Landscape Vegetation Database [ucfpl-1997] (with its recommendation)
Landscaping Can Be Attractive & FIREWISE: TREES [SCFC Fire Smart plant-form sections] (with its recommendation)
Κανονισμός Πυροπροστασίας Ακινήτων εντός ή πλησίον δασικώ…: section 5.4.2, paragraph following Table 2δi [greece-2023-fire-resistant-examples] (with its recommendation)
The evidence
Grouped by what each source concluded. Primary evidence rated the plant itself
(a lab, field program, or original curation); corroboration compiled or
republished another source's rating and resolves to its root lineage.
“Fire-Resistant Plant Materials for Oregon”
· condition: green
Populus species (Aspen/cottonwoods) is listed under “Trees—deciduous”. The guide says most listed plants require some irrigation during Oregon's dry summer months and must be maintained in a healthy condition.
“Fremont County Firewise Plant List — Populus sp. — Narrowleaf Cottonwood”
Listed in the source's Large Shrubs and Trees section; the page describes its listed Firewise plants as generally low-growing, low-debris, and relatively moist.
Listed as Co onwood — Populus sp.. The bulletin says fire-resistant plants tend to resist ignition when irrigated and maintained, while fire-prone plants may ignite readily and burn intensely.
11 cited rows from this source; its identity, lineage and tier are stated once.
Primary study Catchpole1998: Catchpole, W.R., Catchpole, E.A., Butler, B.W., Rothermel, R.C., Morris, G.A., & Latham, D. J. (1998) Rate of spread of free-burning fires in woody fuels in a wind tunnel. Combustion Science and Technology, 131, 137.
Shared row context: Sustainability measurement; plant part litter; fuel all; predrying no; device outdoor wind tunnel; site Catchpole1998-1; sampling ND.
