Maine Tree Species Fact Sheet

Common Name: Speckled Alder (Gray Alder, Hazel Alder, Hoary Alder, European Speckled Alder, Mountain Alder, Tag Alder, and Rough Alder)
Botanical Name: Alnus incana  ssp. rugosa
Tree Type: Deciduous

Physical Description:

Growth Habit: The Speckled Alder is a tall, deciduous, thicket-forming, rhizomatous shrub or small tree.  The bark is thin, smooth and dark chocolate brown with conspicuous (1/6-1/3” long) white lenticils.  The leaves are alternate, simple, 2-3 inches long and broadly ovate with a row of 2 distinctly different sized teeth along the margin.  They are a dull dark green in color, glabrous (having no hairs), and somewhat wrinkled on the upper surface.   On the underside they are paler and covered with rusty hairs.  The leaf petiole is short, stout, smooth and white dotted. 

Height:  The Speckled Alder rarely grows more than 20 feet in height with a trunk diameter of 4 inches.

Shape:  Alder usually occurs as a coarse shrub and rarely as a small tree.     

Fruit/Seed Description/Dispersal Methods:

The flowers are monoecious, and are in erect ½” long catkins which occur in clusters or 4 to 10.  They open before the leaves in the spring.  The purplish wax-like male catkins are pre-formed the previous fall.  The fruit is an oval winged nutlet borne in egg-shaped cones. 

Range Within Maine:

Speckled Alder commonly occurs statewide, usually growing in wet areas along brooks, in swamps, and in pastures. 

Distinguishing Features:

The Speckled Alder gets its name from the white lenticils that appear on the bark.   Each leaf has a row of 2 distinctly different sized teeth along the margin.

Interesting Features:

The wood is light and soft and has very little commercial use.  It discolors very rapidly once exposed to the air.  Because they easily bend, baskets are often made from small diameter stems.

Relationship to Wildlife:

Songbirds, including American Goldfinch, Pine Siskin and Redpolls feed on the seeds.  Woodcock and grouse eat the buds and catkins.  Moose, muskrats, beavers and rabbits feed on the twigs and foliage.  Thickets provide cover for moose and deer and the beavers use it to build dams and lodges.

Landscape Use:

Speckled Alder is not a species for the home landscape.  It is commonly found on moist wetlands, frequently bordering streams and lakes, swamps and bogs.  Speckled Alder is often planted on streambanks for erosion control.

Common Problems or Pests of the Tree in Maine:

Speckled Alder sprouts very readily and is a nuisance on pastureland. 

References:

A Boundary Water Compendium, http://www.rook.org/earl/bwca/nature/shrubs/alnusincana.html

Forest Trees of Maine, Twelfth Edition.  Maine Forest Service/Department of Conservation. 1995.

Manual of Woody Landscape Plants, 5^th Edition.  Dirr, Michael A.  Publishing L.L.C. 1998.

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