Red Alder - Alnus rubra
Species of Concern
* (see State Rank Reason below)
MNPS Threat Rank
State Rank Reason (see State Rank above)
Rare in Montana, where it occurs only in the extreme western portion of the state. The species is at the eastern end of its range in the state.
- Details on Status Ranking and Review
Red Alder (Alnus rubra) Conservation Status Review
Review Date = 06/01/2012
Score3 - Vey Small: Generally <2,000 individuals.
Score1 - Peripheral, Disjunct or Sporadic Distribution in MT: Widespread species that is peripheral, disjunct or sporadically distributed within MT such that it occurs in <5% of the state (<7,500 sq. miles or the combined area of Beaverhead and Ravalli Counties) or is restricted to 4-5 sub-basins.
CommentPeripheral in northwest Montana
Area of Occupancy
Score2 - Low: Generally occurring in 4-10 Subwatersheds (6th Code HUC’s).
ScoreNA - Rank factor not assessed.
Score0-1 - Low to Medium.
Score0-1 - Low to Moderate Vulnerability.
Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).
Raw Conservation Status Score
7 to 9 total points scored out of a possible 16 (Rarity factors and threats only).
Tree to 20 m with gray bark. Twigs reddish with club-shaped buds. Leaf blades to 15 cm long, with revolute margins 1 to 2-times serrate, gray, pubescent and glandular below. Inflorescence borne on twigs of previous season. Fruit with wings to half as wide as nutlet (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Catkins develop in March-April.
Number of Species Occurrences:
*Not all Species Occurrences are mapped
In MT only in Sanders and Mineral counties; coastal AK and YK south to CA, east to ID and MT (Furlow 1997 in Fl. N. Amer. Vol. 3).
Summary of Observations Submitted for Montana
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Ecological Systems Associated with this Species
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Lesica, P. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.
- Little, E.L., Jr. 1979. Checklist of United States trees (native and naturalized). Agriculture Handbook No. 541. U.S. Forest Service, Washington, D.C. 375 pp.