Alnus rubra

General: Birch family (Betulaceae). Red alder is a deciduous tree native to the Pacific Northwest of North America. The trees are medium-sized, reaching various heights from 15 to 30 meters tall when mature. These fast-growing trees often grow 1 meter per year until 20 years of age. The trees can live to 100 years of age with trunks from 36 to 46 cm in diameter. A shrub form occurs when the trees grow in open exposed areas. The branches are slender and spreading. The thin bark is generally smooth, ashy gray to grayish-brown, and is usually covered with white lichens as it ages. The inner bark is reddish brown.

The alternately arranged leaves are dark green, simple and broadly ovate. The leaves are 6 to 15 cm long with a pointed tip. The leaf edges are serrated or softly lobed and slightly rolled under, giving a dark-green edging effect from the underside of the leaf. The undersides of the leaves are rusty colored and covered with fine soft hairs.

The trees are monoecious, bearing both female flowers and male catkins. The tassel-like catkins grow in cluster of two to four. The catkins are greenish-yellow and 10 to 16 cm long. The flowers appear in spring either before or with the leaves. The flowers develop into small-scaled cones (fruits) that are 2 to 2.5cm long and 1 to 1.5 cm across. Each cone contains from 50 to 100 seeds that are tiny flat nutlets. The abundant seeds are wind dispersed from May to winter months.

Red alder trees invade clearings or burned-over areas and forms temporary forests (Grimm 1967). Over time, red alders build up the soil with their copious litter, and enriched it with nitrogen compounds formed by symbiotic bacteria that live in little nodules on their roots. Red alder stands are eventually succeeded by Douglas fir, western hemlock, and sitka spruce.

Distribution: Red alder is most often observed in moist areas within 200 kilometers of the Pacific Coast of North America from Alaska to Southern California at elevations below 762 meters (Uchytil 1989). It also occurs along streams and lakes from the Yukon Territory and British Columbia south through the Rocky Mountain region to Colorado and New Mexico, and along Sierra Nevada to Lower California (Britton 1908). Red alder has spread to upland areas since European contact because of increased disturbance, such as logging, which opens up sites for colonization.

For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Habitat: Red alder trees are often associated with mixed evergreen forests and redwood forests in coastal areas. The trees grow in riparian forests along streams, in swamps and in marshy areas.

Pacific Coast alder, Oregon alder, western alder,

Red alder is confined to the Pacific Coast region from southeast Alaska
to southern California. Although there is an isolated population
growing along streams in northern Idaho, it ordinarily occurs no further
inland than 100 miles (160 km) at elevations below 2,500 feet (762 m)
[16,24,33]. Red alder is cultivated in Hawaii [71].

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
8 Northern Rocky Mountains

AK CA HI ID OR WA BC

Red alder is most often observed as a lowland species along the  northern Pacific coast. Its range extends from southern  California (lat. 34° N.) to southeastern Alaska (60°  N.). Red alder is generally found within 200 km (125 mi) of the  ocean and at elevations below 750 m (2,400 ft). It seldom grows  east of the Cascade Range in Oregon and Washington or the Sierra  Nevada in California, although several isolated populations exist  in northern Idaho (36).

    .
  -The native range of red alder.

Alnus oregana Nutt.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Alnus rubra Bong.:
Canada (North America)
Mexico (Mesoamerica)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

B.C., Yukon; Alaska, Calif., Idaho, Oreg., Wash.

Canada

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Red alder has two adaptations that allow the trees to colonize bare infertile substrates: 1) the roots have nodules that house symbiotic bacteria which fix nitrogen from the air contained in the pores of the soil, and 2) the seeds need sunlight to germinate.

Actinomycetes (filamentous bacteria) in the genus Frankia invade alders through their root hairs and stimulate cell division, forming nodules on the roots (Pojar & Mackinnon 1994). Species of Frankia remove nitrogen from the air and ‘fix’ it in a form useful to plants (Ibid.). Red alder provides a home for the actinomycete, which in turn ‘leaks’ some of the nitrogen, making it available for the alder (Ibid.). Alder improves soils fertility by fixing atmospheric nitrogen in a form that can be used by other plants. This conversion is why forests stands containing alder generally have a rich understory (Ibid.).

Young trees can survive disturbance by resprouting from the stumps (Labdie 1978). Red alder trees tolerate flooding and can grow in areas where the water is brackish (Brenzel 2001).

More info for the term: tree

Red alder is the largest American alder. It is a rapidly growing,
short-lived, medium-sized, deciduous tree, generally with one straight
distinct trunk. Red alder reaches a maximum height of about 120 feet
(37 m) with a maximum trunk diameter of about 32 inches (80 cm).
However, mature trees are typically from 80 to 100 feet (24-30 m) tall
and 14 to 18 inches (36-46 cm) in diameter [14,25,34,59]. Maximum age is
one hundred years [58]. Trees growing in the Puget Sound area exibit
the following age-growth characteristics [14,34]:

Age Height Diameter Breast Height
(years) (feet/meters) (inches/centimeters)

5 18 / 5.5 ------
10 40 / 12.2 ------
20 65 / 19.8 ------
30 82 / 25.0 11 / 27.9
40 90 / 27.4 13 / 33.0
50 98 / 29.9 16 / 40.6
60 105 / 32.0 18 / 45.7

Red alder has thin (less than 0.75 inch [1.9 cm]), smooth gray-whitish
mottled bark, which is often covered with green moss. The root system
is shallow, but wind throw is seldom a problem, since the leaves are
absent during winter and early spring when winds are the strongest and
when soils are saturated with moisture [59]. Male and female flowers
occur on the same tree in catkins. The drooping staminate catkins are
up to 5 inches (12 cm) long and clustered near the end of a twig. The
pistillate catkins are erect, 0.6 to ).8 inch (1.5-2 cm) long, turning
woody and conelike at maturity [14,26].

Red alder is closely related to white alder (Alnus rhombifolia), and the
two species are difficult to differentiate when growing together.
However, their distribution and habitats do not overlap to any great
extent. In the summer, leaf characteristics can be used to separate
these alders, but in the winter proper identification is based on many
subtle points. Several keys exist for proper identification.

Trees , to 28 m; trunks often several, crowns narrow or pyramidal. Bark gray, smooth, darkening and breaking into shallow rectangular plates in age; lenticels inconspicuous. Winter buds stipitate, ellipsoid, 6--10 mm, apex rounded, long; stalks 2--8 mm; scales 2--3, outer 2 equal and valvate, usually heavily resin-coated. Leaf blade ovate to elliptic, 6--16 × 3--11 cm, leathery, base broadly cuneate to rounded, margins strongly revolute, deeply doubly serrate or crenate, with distinctly larger secondary teeth, apex acute to obtuse; surfaces abaxially glabrous to sparsely pubescent. Inflorescences formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 2--6, 3.5--14 cm; sistillate catkins in 1 or more clusters of 3--8. Flowering before new growth in spring. Infructescences ovoid to nearly globose, 1--3.5 × 0.6--1.5 cm; peduncles 1--10 mm. Samaras ovate or elliptic, wings much narrower than body, irregularly elliptic to obovate, leathery. 2 n = 28.

Alnus oregona Nuttall; A. rubra var. pinnatisecta Starker

More info for the terms: density, mesic, shrubs, vine

Historical evidence suggests that the distribution of red alder was much
more restricted than it is today; it occurred chiefly along streams and
in other wet areas [18]. Continual disturbance over the past 100 years,
primarily from logging, has created an abundance of open areas with bare
mineral soil (both are required for seedling establishment) which red
alder has colonized, thus increasing its acreage dramatically. This is
especially true of uplands, where it was previously infrequent.

Red alder is found primarily within Douglas-fir, western hemlock,
western redcedar, sitka spruce, and grand fir forests in the Pacific
Northwest [16,66,67]. Individual trees or clumps of trees may occur to
varying degrees of mixture within these coniferous forests, but stand
development is best along streams, moist bottomlands, and moist lower
slopes [14,35,66,67]. In these mesic locations, pure stands are nearly
always even-aged. Along the southern portion of its range in California
and in the dry interior valleys of Washington and Oregon, red alder is
restricted to riparian deciduous forests [8,19]. In these areas it may
mix with white alder.

Soils: Red alder occurs on a wide variety of soil types ranging from
well-drained gravels and sands to poorly drained clay or organic soils
[25]. The best stands are found on deep, well-drained loams or sandy
loams of alluvial origin [14,16]. Stands also grow well on residual or
colluvial soils of volcanic origin [14]. Soils under red alder stands
develop higher available and total nitrogen contents than soils under
adjacent coniferous stands because of red alder's ability to fix
nitrogen. Nitrogen accretion rates vary with stand location, vigor,
age, and density, with rates varying from 40 to 300 pounds of nitrogen
per acre (45-355 kg/ha) per year [14,25]. As soil nitrogen increases,
soil pH under red alder stands drops. In coastal Oregon, pure alder
stands had soil pH values averaging 4.3 to 4.4, while adjacent conifer
stands had pH values averaging 5.3 [20]. Red alder leaves also contain
significant amounts of nitrogen. Leaves decompose rapidly, forming a
deep humus and thus improving soil structure [16].

Climate: Red alder grows in humid coastal climates characterized by
cool wet winters and warm dry summers. Mean annual precipitation ranges
from 16 to 220 inches (40-560 cm) [25]; precipitation occurs chiefly as
rain during the winter. Trees need more than 25 inches (64 cm) of
precipitation annually, and most stands are located on sites receiving
in excess of 40 inches (102 cm) [16].

Coniferous forest associates: Red alder grows both in pure stands and
in mixtures with native conifers [67]. Pure and mixed stands are mostly
even aged. Trees generally become established in forest openings
created from a disturbance. As stands develop and trees mature, they
prevent other red alder seedlings from becoming established, due to the
seedlings' shade intolerance. Common coniferous associates include:
Douglas-fir, western redcedar, western hemlock, grand fir, and Sitka
spruce. Red alder communities within coniferous forests contain a
number of deciduous trees and shrubs also. Deciduous trees and shrubs
include bigleaf maple, vine maple (Acer circinatum), Pacific willow
(Salix lasiandra), and bitter cherry (Prunus emarginata). Understory
shrubs and herbs include salmonberry, western thimbleberry, American
devilsclub (Oplopanax horridum), black elderberry (Sambucus racemosa),
trailing blackberry (Rhubus ursinus), Siberian minerslettuce (Montia
sibirica), and false lily-of-the-valley (Maianthemum dilatatum)
[19,21,67].

Deciduous riparian forest associates: In California, red alder chiefly
occurs in riparian forests where it often codominates with Sitka spruce,
redwood (Sequoia sempervirens), black cottonwood, bigleaf maple, and
Pacific willow [54,56]. Along larger rivers in Oregon and Washington,
red alder typically codominates with bigleaf maple, Oregon ash (Fraxinus
latifolia), black cottonwood, and willows (Salix spp.) [18,19]. Other
deciduous forest associates include Pacific wax-myrtle (Myrica
californica), Pacific red elder (Sambucus callicarpa), and California
laurel (Umbellularia californica) [18,56].

Elevation: Red alder is generally found no farther inland than 100
miles, at elevations below 2,500 feet. Elevational ranges for several
western states are presented below [16,33,34,48,66]:

from sea level to 500 feet (0-152 m) in CA
1,030-3,600 feet (314-1,097 m) in ID
sea level to 2,500 feet (0-762 m) in OR
sea level to 2,500 feet (0-762 m) in WA

More info for the terms: climax, codominant, hardwood, shrub

Red alder communities, both upland and riparian, generally are found
within coniferous forests dominated by Douglas-fir (Pseudotsuga
menziesii), western redcedar (Thuja plicata), western hemlock (Tsuga
heterophylla), grand fir (Abies grandis), and Sitka spruce (Picea
sitchensis) [18,19,67], or as components of deciduous forests of
floodplains or swamps [18,19]. Generally, five types of red alder
communities have been described [18,19,21,32,67]:

(1) Upland, pure even aged stands of red alder, with a dense shrub
undergrowth dominated by salmonberry (Rubus spectabilis) or
elderberry (Sambucus melanocarpa), occurring within coniferous
forests.

(2) Upland mixed stands of red alder/other deciduous trees and
shrubs/conifers within coniferous forests less than 100 years
old, with red alder occurring as a dominant or codominant.

(3) Riparian red alder communities within coniferous forests.

(4) Mixed stands within deciduous riparian forests, red alder
occurring as codominant with black cottonwood (Populus trichocarpa)
and bigleaf maple (Acer macrophyllum).

(5) In swamps often occurring with, or codominant with, western
redcedar. In this type of community, red alder appears to be a
climax species.

Red alder communities were primarily restricted to streams and wet areas
during presettlement times. Since then, disturbances such as logging
have provided an abundance of open sites with bare mineral soil, which
favor red alder colonization. Today red alder communities are common
throughout much of coastal Oregon and Washington.

Published classification schemes listing red alder as an indicator
species or as a dominant part of the vegetation in community types (cts)
or plant associations (pas) are presented below:

Area Classification Authority

AK general veg. cts Viereck & others 1992

CA hardwood forest & Barbour 1987
woodland cts

CA general veg. cts Thorne 1976

s CA general veg. cts Paysen & others 1980

nw CA,w Or,w WA general veg. cts Franklin 1979

OR: Siuslaw NF general veg. pas Hemstrom & Logan 1986

OR postburn veg. cts Bailey & Poulton 1968

s OR: Cascade Mtns forest pas Atzet & McCrimmon 1990

OR, WA general veg. cts Franklin & Dyrness 1973

Pacific NW general veg. cts Hall 1984

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES22 Western white pine
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce
FRES27 Redwood
FRES28 Western hardwoods

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

210 Interior Douglas-fir
221 Red alder
222 Black cottonwood - willow
223 Sitka spruce
224 Western hemlock
225 Western hemlock - Sitka spruce
226 Coastal true fir - hemlock
227 Western redcedar - western hemlock
228 Western redcedar
229 Pacific Douglas-fir
230 Douglas-fir - western hemlock
231 Port Orford-cedar
232 Redwood
244 Pacific ponderosa pine - Douglas-fir

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

K001 Spruce - cedar - hemlock forest
K002 Cedar - hemlock - Douglas-fir forest
K003 Silver fir - Douglas-fir forest
K005 Mixed conifer forest
K006 Redwood forest
K012 Douglas-fir forest
K013 Cedar - hemlock - pine forest
K025 Alder - ash forest
K029 California mixed evergreen forest

Red alder grows in climates varying from humid to superhumid.  Annual precipitation ranges from 400 to 5600 mm (16 to 220 in);  most of the precipitation is rain in winter. Summers are  generally cool and dry. Temperature extremes range from -30°  C (-22° F) in Alaska and Idaho to 46° C (115° F)  in California. Low winter temperatures and lack of precipitation  during the growing season appear to be the main limits to the  range of red alder. For good development of trees, either annual  precipitation should exceed 630 mm (25 in) or tree roots should  have access to ground water.

Stream banks, moist flood plains, lake shores, wet slopes, and sandy, open coasts; 0--300m.

Red alder prefers moist, well-drained, deep sandy loams (Labadie 1978) and full sun. Quick growing red alders can be planted with slower growing trees such as oak to provide quick screening (Lowry 1999).

Propagation from Seed: Red alder trees are generally propagated from seed. Mature seeds can be collected beginning in May. Spring sown seeds of Alnus rubra should germinate successfully as long as they are not covered as the seeds require sunlight to germinate and germinate best in full sun. Sow the seeds in containers or seed trays containing a slow release fertilizer. Firm the medium and place the seeds thinly and evenly on top. When large enough to handle, the seedlings can be placed into individual pots. If growth is sufficient, they may be planted into their permanent positions in the summer, if not they can be planted the following spring.

The seeds do not require pretreatment, however germination can be improved by cold stratification for 1 to 3 months (Emery 1988). To do this, mix the seeds with three parts moistened peat moss or vermiculite. Place the mixture into an airtight jar or sealed plastic bag in the refrigerator for 1 to 3 months before planting. This process is not necessary if the seeds are planted in the fall, as the temperatures and moisture over winter will accomplish the same purpose.

Foodplant / parasite
hypophyllous uredium of Melampsoridium betulinum parasitises live leaf of Alnus rubra
Remarks: season: 8-10
Other: unusual host/prey

Red alder grows in both pure and mixed stands. Pure stands are  typically confined to stream bottoms and lower slopes. Red alder  is, however, much more widely distributed as a component of mixed  stands. It is a major component of the forest cover type Red  Alder (Society of American Foresters Type 221) and occurs as a  minor component in most of the other North Pacific cover types  (11).

    Common tree associates are Douglas-fir (Pseudotsuga  menziesii), western hemlock (Tsuga heterophylla), western  redcedar (ThuJa plicata), grand fir (Abies grandis),  Sitka spruce (Picea sitchensis), black cottonwood  (Populus trichocarpa), bigleaf maple (Acer  macrophyllum), and willow (Salix spp.). Occasional  tree associates include cascara buckthorn (Rhamnus  purshiana), Pacific dogwood (Cornus nuttallii), and  Oregon ash (Fraxinus latifolia). Western paper birch (Betula  papyrifera var. commutata) is an occasional associate  in the northern portion of the range of alder, and redwood (Sequoia  semperuirens) in the southern portion.

    Common shrub associates include vine maple (Acer circinatum),  red and blue elder (Sambucus callicarpa, S. cerulea),  Indian plum (Osmaronia cerasiformis), salmonberry  (Rubus spectabilis), western thimbleberry (R.  parviflorus), dlevilsclub (Oplopanax horridum), Oregongrape  (Berberis nervosa), and salal (Gaultheria shallon).

    Herbaceous associates include stinging nettle (Urtica dioica),  skunkcabbage (Lysichitum americanum), blackberries  (Rubus laciniatus, R. leucodermis), California dewberry  (R. ursinus), swordfern (Polystichum munitum), lady  fern (Athyrium filix-femina), Pacific water parsley (Oenanthe  sarmentosa), youthon-age (Tolmiea menziesii), Oregon  oxalis (Oxalis oregana), and western springbeauty (Montia  sibirica).

White alder (Alnus rhombifolia) was also widely used for the same purposes as red alder by Native American tribes. White alder occurs in inland areas while red alder generally grows in areas of maritime influence. Red alder and white alder can be difficult to distinguish from each other. White alder does not have red inner bark or rolled leaf margins.

Red alder is fairly free from  most insect and disease problems, especially when young (age 40  or 50) and uninjured (21,45). Phellinus igniarius, a white heart  rot, is probably the major cause of cull in older trees. Three  canker-causing stem diseases-Didymosphaeria oregonensis,  Hymenochaete agglutinans, and Nectria galligena-cause some  damage, especially in young stands, but their overall impact is  slight. Red alder has a number of foliage and catkin diseases,  but none are economically important. Many species of fungi have  been identified on alder; but, except for those discussed above,  they tend to be secondary invaders on dead or dying tissue. Wood  stain and decay proceed rapidly in cut trees, and logs should be  processed soon after harvest unless they are stored in fresh  water (43). During intermediate cuts, care must be taken to avoid  injuring residual trees; once trees are injured, decay organisms  can invade rapidly.

    Insect pests are not usually a major concern, but serious  outbreaks of some defoliators can cause growth reductions. The  forest tent caterpillar (Malacosoma disstria), western tent  caterpillar (M. californicum), alder woolly sawfly (Eriocampa  ovata), striped alder sawfly (Hemichroa crocea), the alder flea  beetle (Altica ambiens), and a leaf beetle (Pyrrhalta  punctipennis) have caused substantial damage; but reports of  mortality are rare (5,13,45). A flatheaded wood borer (Agrilus  burkei) can kill twigs and branches (5,13). The alder bark beetle  (Alniphagus aspericollis) breeds primarily in slash and in young  stressed trees; however, healthy trees can be attacked when bark  beetle populations are high (5). Ambrosia beetles (Gnathotrichus  retusus, 7~-ypodendron lineatum, Xyleborus saxeseni) attack logs  and slash left on the ground, causing rapid degrade in quality.  Insect holes can also serve as entry sites for fungi.  Merchantable material should be removed rapidly, and large  accumulations of slash should be avoided.

    Animals cause only minor damage in alder stands. Young trees are  occasionally browsed by black-tailed deer, especially during the  late summer and fall (6), but alder is not a preferred species.  'Mountain beaver sometimes girdle small stems and branches; their  use of alder foliage for food is minor and sporadic except in  late September when use is fairly heavy (38). In years of high  populations, meadow mice girdle young stems. Damage by meadow  mice has been most commonly observed in grassy or very wet areas.

    Climatic factors can damage red alder. Mortality and top damage  have been documented in natural stands after ice storms or  unseasonable frosts (10,45). Fire is rarely a damaging agent  because of the scarcity of flammable debris in alder stands; in  fact, the species sometimes has been planted as a firebreak to  protect adjacent conifers (45). Alder bark is thin but  sufficiently fire resistant to prevent damage during light  surface fires (43). Windthrow is not common in alder because of  the intermingling of roots and branches, the absence of leaves  during winter storms when soils can be waterlogged, and the  relatively deep-rooting habit of the species on well-drained  soils. Uprooted trees are most commonly observed along cutting  boundaries or where established root systems have been undercut  by flooding or erosion.

More info for the term: litter

Fire hazard is generally low in red alder stands. Stands may be used as
natural fire breaks [67]. The thin litter permits easy construction of
fire lines.

More info for the term: root sucker

Tree with adventitious-bud root crown/soboliferous species root sucker
Initial-offsite colonizer (off-site, initial community)

More info for the term: litter

Red alder's bark, although thin, is sufficiently fire resistant to
protect trees from light surface fires. The foliage and leaf litter do
not carry fires well [1,16]. Red alder stands often lack flammable
understory debris and are often on moist sites which burn infrequently
[14,16]. Red alder revegetates burned areas via seed from off-site plants
[35].

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More info for the term: tree

Red alder is common on many disturbed areas. Many of the stands which
exist today were created because of the pioneering habit of red alder.
Red alder quickly invaded lands clearcut and burned during the 1920's to
1940's [3,39]. In 1920 there was an estimated 1/3 of a billion board
feet of red alder, but by the mid 1960's, red alder acreage increased
dramatically, containing an estimated 12 billion board feet [39]. By
1988, red alder covered an estimated 13 percent of commercial forest
lands along the Pacific Coast of Washington and Oregon [55].

Red alder is an early seral species. It quickly invades forest
openings, such as those created from fires, logging, wind throws, or
road cuts, and it also pioneers volcanic mud flows [19,46]. Red alder
and Douglas-fir are reported as the principal pioneer tree species of
lower and middle elevation forests from southwestern British Columbia to
northwestern California [41]. Thus they often dominate the first
postfire community in the Pacific Northwest. Disturbed areas are
naturally seeded by numerous wind-dispersed seeds, resulting in stands
that start out with several thousand alder trees per acre [3]. Due to
red alder's shade intolerance, stands are self-thinning; trees that do
not maintain their height in the canopy die, resulting in even-aged
stands [17,66]. Conifers such as Douglas-fir that become established at
the same time are quickly overtopped by this extremely fast growing
species. These early seral red alder communities suppress competing
conifers, but after about 25 years, conifers equal red alder height and
begin to overtop them. After about 40 years, Douglas-fir becomes
dominant. Few red alder trees remain in stands past 60 years [16,67].

More info for the terms: duff, monoecious, natural

Sexual reproduction: Red alder regenerates primarily by seed. Plants
are monoecious and are primarily wind pollinated. Flowering generally
occurs from late February to early May depending on latitude and climate
[36]. After fertilization female catkins develop into woody cones about
0.5 to 1 inch (1.2-2.5 cm) long, containing 50 to 100 small, flattened,
winged, nutlike seeds [16,67].

Seed dispersal and production: Seed dispersal begins soon after
ripening in late summer, but most seeds are shed during fall and winter
[14,66]. The seeds are very lightweight (about 666,000/pound
[1,465,000/kg]) and are normally carried up to several hundred yards in
the direction of the prevailing winds. Seed production begins at about
10 years [58] (but sometimes sooner), and continues throughout maturity,
with optimum production at about 25 years of age [36]. A prolific
seeder, red alder produces peak crops about every 4 years, with moderate
to light crops produced in between [36]. Total seed crop failure is
very rare; however, a total crop failure did occur following a severe
freeze in November 1955 [16,36].

Germination: Under natural conditions, germination occurs in the
spring. Germination is best on moist mineral soil in full sunlight
[14,36]. Seed also germinates well on rotten wood and duff [45], and to
a lesser extent on soil organic horizons and on rock-surfaced logging
roads, but the roots must quickly penetrate to a moist nutritious
substrate if seedlings are to survive [14]. Sunlight is required for
germination [36]. Seeds under thick vegetation or buried deeply in the
soil, willnot germinate until the site is disturbed, exposing the seeds
to sunlight. Germination percentages range from 59 to 84 percent
[52,58]. Germination rates of stratified and nonstratified seeds are
about equal. Low germination percentages may be due to a high
proportion of empty seeds known to occur in red alder [52]. Seeds
remain viable in storage for about 3 years [25].

Seedling establishment: Generally, exposed mineral soil is needed for
seedling establishment. Seed production is normally so prolific that
dense stands quickly develop on exposed soils of logging roads,
clearcuts, and burned over areas [25]. These areas may have from
several hundred thousand to several million red alder seedlings per
hectare in the spring of the first year after the disturbance [69].
Regeneration and establishment in dense, thick, brush fields is
infrequent due to the lack of exposed sights, but any disturbance which
removes the brush and exposes the soil will favor red alder
establishment [67]. Plants often reach 6 to 18 inches (15-45 cm) in 1
year and may reach 18 feet (5.5 m) in 5 years [16]. This rapid juvenile
growth gives the shade-intolerant red alder a competitive edge over
conifers, as it quickly overtops them.

Vegetative reproduction: Red alder will sprout following an injury to a
stem, but in the absence of disturbance, sprouting is infrequent. Red
alder's sprouting ability following cutting is summarized as follows
[25,27]:

(1) Sprouting vigor is greatest on trees 1 to 3 years old. Vigor falls
off dramatically after 15 years. Trees 15 years or older
rarely have live sprouts 2 years after cutting.

(2) The average number of sprouts per cut stem increases significantly
as stump height is increased.

(3) Stumps with the cut surface facing south or west have the least
mortality and are most likely to sprout.

(4) Level cuts have higher mortality and fewer sprouts than angled
stumps.

(5) Stems cut in January have the lowest mortality; stems cut during the
growing season, especially July or August, have the highest
mortality.

(6) The number of sprouts per cut stem is not affected by the season of
cutting.

Propagation: Cuttings of red alder do not root easily [66].

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More info for the term: phanerophyte

Phanerophyte

More info for the term: tree

Tree

Red alder is an early seral species which quickly invades burned areas.
Off-site plants inhabiting fire resistant draws and streambeds provide
an abundance of seed, which reportedly can travel several hundred yards
via wind. Thus red alder quickly colonizes soils exposed after forest
fires. Red alder along with Douglas-fir are often the dominant postfire
vegetation on low to middle elevation sites throughout the Pacific
Northwest [41]. Red alder may dominate and suppress conifers following
a fire for 20 to 25 years, after which the conifers overtop the alder
[68].

Information regarding the sprouting response of red alder after
aboveground plant parts have been killed by fire is lacking. However,
responses after cutting show that red alder tends to sprout at the root
collar or along the lower stem no matter where the stem is cut [27]. For
detailed information regarding the sprouting response of red alder after
cutting, refer to the Regeneration Slot.

Information regarding the effects of fire on red alder is lacking.

Red alder requires more light  than any of its tree associates except black cottonwood and is  classed as intolerant of shade. Young seedlings can withstand  partial shade for a few years but will grow very little; if not  released, the seedlings will die. The only trees that survive are  those that maintain dominant or codominant crown positions.  Self-thinning or mortality caused by competition is rapid, and  mean densities in natural stands decrease from 124,000 seedlings  per hectare (50,000/acre) at age 5 (7) to 1,665 seedlings per  hectare (675/acre) at age 20 (44). Red alder also selfprunes  extremely well. Shaded lower branches rapidly die and fall off;  alder holes are typically clear and slightly tapered (fig. 3).  Live crown ratios in crowded, pure stands are very low, and  narrow, domelike crowns are characteristic.

    Early control of spacing is necessary to keep live crown ratios  high enough to maintain good growth beyond the juvenile phase.  Saw-log yields can be maximized on short rotations by combining  early spacing control with pulpwood thinnings (5). Thinnings in  previously unthinned stands are most effective in stimulating  growth of residual trees if done before height growth slows-about  age 15 to 20 (5,28,39). Thinning in older stands can salvage  mortality and help maintain the vigor of residual trees but does  not usually accelerate diameter growth (25,40).

    Epicormic branching has been reported after thinning, especially  when thinning has been late or drastic (1,40). Epicormic  sprouting is most commonly observed on the south side of stressed  trees. Epicormic branches appearing after early thinning are  usually ephemeral and not cause for concern.

    Red alder can be grown in either pure or mixed stands. Creation or  maintenance of mixed stands requires careful attention to the  respective heightgrowth patterns and tolerances of the species.  Alder must be kept in the upper canopy to survive in mixed  stands.

Red alder forms extensive, fibrous  root systems. Root growth of seedlings is rapid; 2-year-old  nursery-grown seedlings have to be planted using a shovel because  of their wide-spreading, large, woody roots.

    Red alder roots are commonly ectomycorrhizal. Only a few species  of fungi, however, are capable of forming ectomycorrhizal  associations with alder. Fungal symbionts include an  alder-specific fungus (Alpova diplophloeus) and fungi  capable of mycorrhizal associations with other hosts (Paxillus  inuolutus, Astraeus pteridis, and Scleroderma hypogaeum)  (26).

    Red alder also has root nodules that fix atmospheric nitrogen. The  nodules are a symbiotic association between the tree and an  actinomycete (Frankia spp.). Nodulation occurs soon after  seed germination; root systems of seedlings a few months old  commonly have dozens of visible nodules, ranging from the size of  a pinhead up to 25 min (1 in) in diameter. Mature trees have  nodules on both the large woody roots and the smaller new roots.  Nodules found on large trees can be as large as 80 or 90 mm (3.1  or 3.5 in) in diameter.

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More info for the terms: fresh, tree

Red alder is a deciduous tree. Flowers begin to form in the spring
before the leaves expand. Flowering in Oregon and Washington generally
begins in late February and continues until early May [58]. Fruits
ripen in late summer and early fall; seeds are dispersed during fall and
winter [58] and can often be seen on fresh snow. The following dates
have been recorded for phenological events in Oregon and Washington
[16]:

Phenological Event 17 locations throughout Snohomish County
Oregon and Washington Washington

Leaf bud bursts March 21 - April 23 April 3
Completely leafed out April 9 - May 16 May 2
Flowering begins February 19 - May 4 March 29
Flowers all fallen March 18 - June 5 April 12
Fruit ripe August 5 - October 29 August 27
Leaves mostly fallen September 18 - November 24 November 13

In the Cascade Mountains of Oregon, red alder is one of the first
deciduous trees to lose its leaves. The majority of leaves fall during
October, with virtually all leaves lost by the first week in November
[10].

Flowering early spring.

Red alder sprouts  vigorously from the stump when young. It can be repeatedly  coppiced on short cycles but rootstock mortality increases with  each harvest (17). Age, time of year, and cutting height  influence the likelihood of obtaining stump sprouts and the vigor  of the sprouts (15). Stumps will sprout best when trees are cut  in the winter and when stump height exceeds 4 in (10 cm). Older  trees rarely sprout and coppice regeneration cannot be expected  after polesize or saw-log-size material is harvested (15).

    Greenwood cuttings from young trees can be readily rooted. More  than 50 percent of cuttings from 1to 3-year-old plants took root  within 6 weeks after treatment with 4,000 to 8,000 p/m  indole-3-butyric acid and 10 percent benomyl (27). The cuttings  were set in a well-aerated planting mix and placed in a warm  environment (22° to 25° C; 72° to 77° F) in  the daytime and 16° to 22° C (61° to 72° F)  at night with high relative humidity and a 16-hour photoperiod.

    Cuttings of succulent new spring growth from shoots of 3- to  6-year-old trees and epicormic sprouts from 27- to 34-year-old  trees have also been rooted successfully (30). Best results were  obtained with a 10-second dip in 2,000 or 4,000 p/m  indole-3-butyric acid. The extent of rooting and root vigor on  the cuttings varied greatly among ortets and treatments.

    Red alder can also be propagated by mound layering (41). For this  technique the seedlings are first coppiced. When the sprouts are  a few months old, the stump and the base of the sprouts are  covered with soil. The sprouts soon form roots; they can be  severed from the stump and planted at the end of the first  growing season.

Red alder germinates and  grows well on moist mineral soil with full sunlight. Germination  is epigeal. Seedlings can become established from seeds that fall  on a highly organic surface, such as forest litter. Because the  seeds are so small, however, their food reserves are minimal and  the tender radicle must encounter a moist, nutritious substrate  almost immediately after germination if the seed is to become an  established plant. Seedlings can tolerate partial shade for  several years, but after that full sun is required for normal  development.

    Red alder can be regenerated by any method that provides full  sunlight and exposed mineral soil. The species is an aggressive  pioneer on avalanche paths, road cuts, log landings, skid trails,  or other areas where mineral soil has been freshly exposed to  seed fall. Clearcutting and large-group selection are feasible  regeneration systems. During harvesting or in a subsequent site  preparation treatment, the site must be disturbed sufficiently to  expose mineral soil. Fire can probably substitute for mechanical  disturbance on most sites. To exclude red alder from the next  rotation stand, some forest managers try to reduce the supply of  alder seed by cutting possible alder seed trees in the vicinity  before or at the time of final harvest, and also to avoid  creating favorable seedbed conditions by disturbing the site as  little as possible during logging and, if feasible, by not  burning the logging slash.

    Artificial regeneration can be accomplished with either bare-root  or containerized seedlings. Dried, stored seed need not be  stratified (2,29). Nursery production of seedlings is fairly  trouble free if standard techniques are used; sowing should  generally be done fairly late (in June), however, to prevent the  development of seedlings too large to be easily handled by  planting crews. If the soil is sterilized, it may be necessary to  reinoculate it to speed formation of mycorrhizae and root  nodules. Guidelines for producing containerized seedlings are  available (2), covering seed treatment, inoculation methods, and  growth media. Survival and growth of planted seedlings are  usually excellent.

    Height growth of red alder seedlings is exceptionally rapid. On  favorable sites, seedlings can grow 1 m (3.3 ft) or more the  first year and on all but the poorest sites, seedlings surpass  breast height (1.37 m; 4.5 ft) the second year (16). Maximum  annual height growth of more than 3 m (9.8 ft) a year can be  achieved by 2- to 5-year-old seedlings (16).

    Seasonal growth of red alder is under strong climatic control and  consequently quite variable. The timing of radial growth is  similar for red alder and its common associate Douglas-fir; in  the Puget Sound area of Washington State, growth Begins about  midApril and continues until mid-September (32). Height growth  begins slightly later in the season than radial growth. Red alder  has indeterminate height growth; thus, height growth continues  through the growing season until soil moisture, temperature, or  light conditions become unfavorable.

Red alder is a  prolific and consistent producer of seed. Moderate seed crops are  produced almost annually and bumper crops occur every 3 to 5  years. Complete failure of a seed crop is rare, but after a  severe freeze in November 1955, almost no seed was produced in  1956 (43).

    The seeds are small, winged nuts borne in pairs on the bracts of  woody, conelike strobili (33). The strobili are 11 to 32 mm (0.4  to 1.3 in) long, and 8 to 15 min (0.3 to 0.6 in) wide. Seed  dispersal begins in late September in the middle of the  species'range, somewhat earlier in Alaska, and several weeks  later in California. Most of the seeds are shed during late fall  and winter. For minimum loss of seeds, cone collection should  begin in September in Alaska and continue until December in  California.

    Red alder seeds are very light, numbering 800 to 3,000/g (22,900  to 85,700/oz), and wind dissemination is effective. The seed can  be carried long distances by wind, and abundant seed for natural  regeneration is usually present throughout the range of red  alder.

Red alder reaches sexual maturity  at age 3 to 4 years for individual trees and age 6 to 8 for most  dominant trees in a stand (5). It is generally monoecious, with  separate male and female catkins developing on the previous  year's twigs (22). Staminate catkins occur in pendulous clumps.  In late winter they elongate, changing from green to reddish  brown and from 2 to 3 cm (1 in) long to about 7 or 8 cm (3 in).  Pistillate catkins also occur in clumps but are borne upright.   They are 5 to 8 min (0.2 to 0.3 in) long and reddish green when  receptive. Flowering occurs in late winter or early spring; peak  shedding of pollen generally precedes peak receptivity by only a  few days. Most alder seed is probably the result of outcrossing,  but some selfpollination does occur (5).

Red alder has rapid juvenile  growth; of its associates, only black cottonwood grows as much or  more during the juvenile phase. On good sites, trees may be 9 in  (30 ft) at age 5, 16 in (52 ft) at age 10, and 24 in (79 ft) at  age 20. One tree was 9.8 in (32.1 ft) tall and 16.3 cm (6.4 in)  in d.b.h. 5 years from seed (36). Mean annual production in 7to  12-year-old thickets has been estimated (oven-dry) at 15.4 t/ha  (6.8 tons/acre) (5).

    Growth slows after the juvenile stage, the decrease beginning much  sooner on poor sites. Site index as determined at base age 20  years ranges from 10 to 25 in (33 to 82 ft) (16); at base age 50,  it ranges from 18 to 37 in (60 to 120 ft) (44). Associated  conifers have much slower juvenile growth, but they sustain  height growth years longer than alder. On an average site, both  Douglas-fir and red alder can attain the same height at about age  45 (36). Beyond that age, Douglas-fir surpasses red alder in  height.

    Red alder is a relatively short-lived species, maturing at about  60 to 70 years; maximum age is usually about 100 years (45). On  favorable sites, trees can be 30 to 40 m (100 to 130 ft) tall and  55 to 75 cm (22 to 30 in) in diameter. A record-size tree  measured 198 cm (78 in) in d.b.h., but trees over 90 cm (35 in)  in diameter are rare. Maximum cubic volume is attained at age 50  to 70 (500 m'/ha or 7 ' 150 ft'/acre) (5,44). In pure stands on  good sites, it has been estimated that red alder can achieve  annual cubic volume growth rates of 21 m'/ha (300 ft'/acre) in  pulpwood rotations of 10 to 12 years, and 14 m/ha (200 ft'/acre)  in saw-log rotations of 30 to 32 years (5). Most of the existing  alder volume is in mixed stands where growth and yield are  variable.

Population Differences    Population differences in height growth, diameter growth, stem  form, bark thickness, and resistance to frost or insect attack  have been demonstrated in a provenance trial in coastal Oregon  involving 10 sources from the range of red alder (5). High growth  rates were positively correlated with good form but negatively  correlated with resistance to spring frosts. Differences among  provenances in bole volume or aboveground biomass were greater  than differences in height or diameter alone (24). Specific  gravity did not differ significantly among provenances, nor was  it correlated with growth rate (17).

    The fastest growing trees in the provenance trial were from  northwestern Washington, but trees from British Columbia,  southwestern Washington, and Oregon also grew well. The slowest  growing trees were from Alaska and Idaho. Thus, it appears  reproductive material of red alder can be moved to mild sites  over fairly long distances along the Pacific coast.

    Differences in form and in characteristics of branch, bark, and  wood among eight stands in western Washington have also been  assessed (5). Variability among trees in a stand was high; only  bark thickness, a branch diameter index, branch angle, and a  crown-width index differed significantly among stands.

    A cut-leaf variety (Alnus rubra var. pinnatisecta) is  found in a few isolated areas in British Columbia,  Washington, and Oregon. The cut-leaf characteristic is caused by  a single recessive gene (42); thus, the cut-leaf variety can be  used as a marker in genetic breeding studies (5).

    Families varied in their height-growth response to water-table  depth in a 24-family progeny trial in western Washington (23).  Use of genotypes tolerant of waterlogging may enhance growth of  red alder on wet sites.

    Phenotypic variation between trees is high. Studies are underway  to assess genotypic variation and the heritability of various  traits. An individual tree approach for selection has been  recommended for tree improvement programs. Because red alder has  extensive populations of even-aged stands and because of its  reproductive and growth characteristics, the species has the  potential for rapid genetic gains (5).

    Races    No races of red alder have been described. Races may exist,  however, especially in the disjunct populations or in the  extremes of the range. One researcher has divided the species  into three populations (northern, central, and southern) on the  basis of vegetative and reproductive features from herbarium  specimens (12).

    Hybrids    No natural hybrids have been documented, but possible hybrids with  Alnus tenuifolia and A. rhombifolia have been described  where the ranges of these species overlap in Idaho (36). Red  alder has been successfully crossed with A. cordata, A.  glutinosa, A. japonica, and A. sinuata (5).

The following is a representative barcode sequence, the centroid of all available sequences for this species.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Specimens with Barcodes: 9
Species With Barcodes: 1

Rounded Global Status Rank: G5 - Secure

Canada

Rounded National Status Rank: NNR - Unranked

United States

Rounded National Status Rank: N5 - Secure

Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).

Aphids and tent caterpillars and borers can be problems for red alder trees.

Although long-term economic returns are higher with conifer crops than
red alder, under certain conditions red alder should be considered as an
alternative forest crop [29]. Upland sites too wet for Douglas-fir and
hemlock (Tsuga spp.) are well suited for red alder. Red alder may also
be planted onto areas infected with laminated root rot fungus, since
hardwoods are immune to this infection. In Oregon, before an area can
be reforested with red alder, regulations require that permission be
obtained from the Oregon Department of Forestry.

Due to red alder's ability to symbiotically fix atmospheric nitrogen, it
has been proposed for use as a rotation crop before growing conifers
[12,44]. Soil nitrogen accretion rates have shown increases ranging from
40 to 300 pounds per acre (45-355 kg/ha) per year under red alder stands
[25]. Conifer stands which follow red alder exhibit increased growth and
yields [2,67]. Studies have shown that Douglas-fir grown with red alder
had increased heights and diameters compared to Douglas-fir grown
without alder [43]. Research on aboveground biomass accretion rates in
red alder stands suggests that for crop rotations, red alder should be
harvested before age 20 [69]. This is because maximum annual
productivity occurs between 10 and 15 years, and stands older than 20
years show signs of deterioration. Red alder stands reach an
aboveground biomass plateau between ages 40 and 50.

Herbicides have been used both to promote the growth of alder and to
kill alder to promote the growth of conifers. To achieve desired
stocking and distribution in potentially harvestable red alder stands,
thinning and culling of selected red alder trees may be desirable.
Numerous chemical applications are available to control red alders which
are are competing with Douglas-fir or other valuable conifers. Stands
may be aerially sprayed, or individual trees can be spot sprayed or
injected. The most common chemicals used for control of red alder are
2,4-D, Tordon 101, triclopyr ester, and triclopyr amine [9,29,49].
Proper guidelines for the use and application of chemicals should be
followed [9,29,49,62].

These plants are readily available through native plant nurseries.

If desired, red alder trees can be pruned for shape when young (Labadie 1978). Follow up pruning is minimal and consists of removing any suckers that may form as well as removing dead wood or crossing branches.

Red alder wood is diffuse-porous, moderately dense, and uniformly  textured. It is used in the production of solid wood products,  such as furniture, cabinets, case goods, pallets, and novelties  (31); composite products, including plywood and flakeboard (5);  and fiberbased products, such as tissues and writing paper.

    Alder is a common fuelwood and is burned both in home fireplaces  and stoves, and in mills that use residues to produce heat for  drying and other processes (31). Because of its rapid juvenile  growth and ability to coppice, red alder has been evaluated for  use in biomass farms for energy conversion (5); some experimental  plantings have been made to evaluate yields under intensive  management.

    The ability of red alder to fix atmospheric nitrogen can result in  increases in both nitrogen content and its availability in the  soil. Nitrogen fixed irr the nodules is added to the soil in four  ways: direct excretion from living roots or nodules,  decomposition of dead roots or nodules, leaching from foliage,  and decomposition of litter rich in nitrogen. Fixation rates vary  diurnally and seasonally (37) and with site and stand age (3,36).  Maximum annual fixation rates of 320 kg/ha (290 lb/acre) (36,  based on accretion) in pure stands and 130 kg/ha (120 lb/acre)(3,  based on acetylene reduction assays) in mixed stands have been  reported.

    Red alder also increases the organic matter content in the soil  (34,36). Concomitant with increases in soil organic matter,  decreases in soil bulk density and pH have been reported  (4,34,36).

    Red alder has been proposed for use alone and in both crop  rotation and mixture with other species (8). Because of its  ability to add nitrogen and organic matter to a site and its  rapid juvenile growth on a variety of sites, the species has been  experimentally planted as follows: (a) to serve as a nitrogen  source for other species (particularly Douglas-fir and black  cottonwood) (5,9); (b) on coal mine spoils, landslides, and other  eroded or low fertility areas (20,35); (c) for streambank or  roadside protection; (d) in areas of poor drainage; (e) as a  firebreak or windbreak (5,34); and M for wildlife areas.

    An additional experimental use of red alder in a crop rotation  system is to plant it in areas containing coniferous root  pathogens, such as Phellinus weiri, which can survive for  many years in organic materials in the soil (14). The only known  control is to replace the disease-susceptible species with a  nonsusceptible species for 40 to 50 years. Red alder is a good  candidate for such an interim species.

    Other experimental uses of alder include addition of foliage,  twigs, and sawdust to grain or alfalfa for cattle feed and  addition of sawdust to nursery soils to increase organic matter.

Ethnobotanic: Native American tribes from Alaska to Southern California have long recognized the value of red alder and put its bark layers, roots, leaves, twigs, cones, and sap to use for a variety of purposes. The inner bark was often dried, grounded into a powder and then used as a thickener in soups or mixed with cereals when making bread.

Various layers of the red alder bark yield red, red-brown, brown, orange, and yellow dyes (Moerman1998). The various colors from the bark were used to color baskets, hides, moccasins, quills, and hair. The native Americans of the Pacific Northwest extracted a red dye from the inner bark, which was used to dye fishnets. Oregon tribes used the innerbark to make a reddish-brown dye for basket decorations (Murphey 1959). Yellow dye made from red alder catkins was used to color quills.

A mixture of red alder sap and charcoal was used by the Cree and Woodland tribes for sealing seams in canoes and as a softener for bending boards for toboggans (Moerman 1998).

Wood and fiber: Red alder wood is used in the production of wooden products such as food dishes, furniture, sashes, doors, millwork, cabinets, paneling and brush handles. It is also used in fiber-based products such as tissue and writing paper.

In Washington and Oregon, it was largely used for smoking salmon. The Indians of Alaska used the hallowed trunks for canoes (Sargent 1933).

Medicinal: The North American Indians used the bark to treat many complaints such a headaches, rheumatic pains, internal injuries, and diarrhea (Moerman 1998).

The Salinan used an extract of the bark of alder trees to treat cholera, stomach cramps, and stomachaches (Heinsen 1972). The extract was made with 20 parts water to 1 part fresh or aged bark. The bark contains salicin, a chemical similar to aspirin (Uchytil 1989).

Infusions made from the bark of red alders were taken to treat anemia, colds, congestion, and to relieve pain. Bark infusions were taken as a laxative and to regulate menstruation. The Pomo boiled the bark in water to make a wash to treat skin irritations and sores (Goodrich et al. 1980). Bark poultices were applied to reduce swelling. Chewing the bark helped to heal sores and ulcers in the mouth.

Externally the sap was applied to cuts and a poultice of the bark has been applied to eczema, sores, and aches (Moerman 1998). The twigs were made into infusions that served as liniments for sprains and backaches.

Basketry: The roots of red alder were used in baskets made by the Hupa, Whilkut, Nongatl, Lassik, Wailaki, Yurok Wiyot, and Pomo tribes (Merrill 1923). Red alder roots form the brown pattern in baskets made by the Whilkut tribe of northwestern California.

Wildlife: Deer and elk eat the leaves, twigs, and buds. Red alder seeds attract many bird and small mammal species including redpolls, siskins, goldfinches, and mice. Most of the seeds remain on the tree well into the fall and winter months, providing valuable resources for seed-eating birds, insects and mammals when other foods are scarce. Beavers eat the bark and build dams and lodges with the stems. Red alder trees provide valuable nesting for birds and thermal cover for black-tailed deer and other wildlife.

Livestock: Horses, cattle, sheep and goats browse on the leaves, twigs and buds of young alder trees.

Conservation and erosion control: Red alder is an excellent species for re-establishing woodlands. The trees are used in forested riparian buffers to help reduce stream bank erosion, protect water quality, and enhance aquatic environments. Plantings of red alder are effective in controlling erosion on steep slopes in disturbed areas (Uchytil 1989). These fast-growing trees help to prevent soil erosion because of their dense canopy cover and thick litter layer that forms within the first 3 to 5 years. The leaf litter is high in nitrogen content (Labadie 1978).

Wood: Red alder wood is a high quality hardwood with a fine, even textured, cherry-like grain that is important commercially in the Pacific Northwest (Labadie 1978). It is used for cabinetry and furniture making as well as a variety of other purposes including plywood, veneers, paneling, pulp, and firewood.

Other: The small cones cling to the branches long after the leaves have fallen and make decorative additions to flower arrangements (Brenzel 2001).