VALUE AND USE
SPECIES: Larix occidentalis | Western Larch 



WOOD PRODUCTS VALUE : 
Western larch is primarily used for construction lumber because of its
strength and hardness.  It makes excellent utility poles because of its
length, form, and strength.  It is also used in plywood manufacture and
to make fine veneer [118].  In lower montane forests of Montana, western
larch is the preferred timber species because it grows larger and yields
more clear timber than Douglas-fir [96].  Wood anatomy has been examined
in detail [83,148].  Two other wood products obtained from western larch
are arabinogalactan, a water-soluble gum used industrially, and
oleoresin, used to produce turpentine and related products [118].  The
wood is excellent fuel.  Wood from western larch snags can be made into
shakes [4].


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Deer, elk, moose, black bear, grizzly bear, and many species of birds
and small mammals occur in seral western larch forests.  Western larch
stands frequently occur in areas of heavy snowpack that are unsuitable
for critical winter range for big game animals [116,118].  When western
larch stands are thinned, they have good potential for livestock forage
production [150].

Western larch needles are a major food source for the blue grouse and
spruce grouse [4].  The red crossbill eats some western larch seed [75].
Seed-eating small rodents prefer larger Douglas-fir and pine seed but
consume some western larch seed [9,132].  Squirrels cut and cache
western larch cones in years when other conifers have poor crops
[116,118].  Western larch is browsed sparingly by elk, deer, and moose
during winter when other food is scarce [35,116,118].  Bears or
porcupines may eat the inner bark of western larch saplings and poles in
the spring [116,118].


PALATABILITY : 
Western larch appears to be unpalatable to most big game animals, but it
is eaten as emergency food [116,118].  Its seeds are palatable to small
birds and mammals, although larger seeds are preferred [9,132,116].


NUTRITIONAL VALUE : 
Western larch needles at two locations in eastern Washington contained
2.0 percent and 1.7 percent nitrogen, respectively [40].  Nutrient
values for western larch needles, twigs, and other tree parts have been
reported from two sites in western Montana [137].  Whole tree values
have also been published [136].  Green needles from Lubrecht
Experimental Forest, Montana had a mean ash content of 5.8 percent and a
range of 3.47 to 8.16 percent, while green needles from Coram
Experimental Forest, Montana had a mean ash content of 5.3 percent and a
range of 4.9 to 8.9 percent.  Nutrient values for needles are summarized
below [137]:

                    Lubrecht Forest                 Coram Forest 
                - - - - - - - - micrograms per gram - - - - - - - -

                 Mean          Range            Mean          Range
Calcium         3,031       2,000-4,800        2,213       1,980-2,390
Copper              8.3       5.0-15.2            15.5      10.7-35.2
Iron               86.8        41-173            126         109-218
Potassium       6,405       2,800-9,760        4,958       4,390-5,388
Magnesium       1,098         692-1,592        1,083       1,005-1,113
Manganese         216          81-405            181         160-239
Nitrogen       13,518       9,730-15,540      23,320      17,920-28,923
Sodium             61.4      24.4-123.0           56          45-125
Phosphorus      2,343       1,678-3,186        2,960       1,894-3,269
Zinc               15.8       6.0-35.6            24.6      21.1-27.7


COVER VALUE : 
Western larch snags provide nesting areas for cavity-nesting songbirds,
woodpeckers, and owls [4,116,118].  Around 25 percent of the birds that
nest in the northern Rocky Mountains make or use tree cavities.  Western
larch, with its decay-resistant sapwood, is a preferred species [77,78].
The holes are also used for protection during storms and as roosting
sites [78].  Both snags and live western larch are used by cavity
nesters [77].  Flying squirrels may nest in holes in western larch
snags.  The osprey, bald eagle, and occasionally the Canada goose build
platformlike nests on top of western larch snags [4].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Western larch's rapid early growth, fire resistance, and the litter
layer produced by its deciduous needles make it useful for
rehabilitation on well-drained moist sites within its range [145].
However, it does not compete well with grasses and shrubs [112].  Seed
collection, stratification treatments, germination tests, and seed
handling have been described in detail [71,106,125].  Spot seeding has
been discussed [118,132].  Direct seeding rates for British Columbia are
given [84].  Detailed information is available on the production and
handling of seedlings [15].  Container-grown seedlings have been
inoculated and successfully formed mycorrhizal root systems with two
fungi, Laccaria laccata and Cenococcum geophilum [86].


OTHER USES AND VALUES : 
Northern Rocky Mountain Native Americans enjoyed a sweet syrup made by
allowing western larch sap to evaporate and concentrate.  They also ate
the cambium layer under the bark in spring and chewed solidified pitch
for gum [51].  Tea made from the bark was used for colds, coughs, and
tuberculosis.  Western larch sap was used for sore throat and gum was
applied to cuts and bruises [51].  In British Columbia decoctions made
from western larch boughs or bark were used as a general tonic, for
respiratory ailments, as a poultice or wash for wounds, as a
contraceptive, to wash babies, and was both drunk and used as a wash for
breast cancer [143].  Boughs were dried for winter use, and western
larch pitch was used on the chest for respiratory ailments and on wounds
[143].  Western larch wood was used to make bowls, as a fuel, and the
rotten wood was used to smoke buckskin.  Kootenai Indians used larch for
the center pole during the religious Sundance [51].

Western larch is easily grown in gardens and parks, although it may
become too large for home gardens.  Seedlings are easy to transplant in
the fall after an early rain and may be treated as bonsai [68].


MANAGEMENT CONSIDERATIONS : 
Management systems:  The ecological requirements of western larch are
best met by even-aged silviculture systems.  It is particularly well
adapted to seed tree cuts and clearcuts [113,116,146].  Clearcutting is
most effective where the overstory trees are infected with dwarf
mistletoe and root rots and may be most practical if western larch
regeneration is desired in a stand with few old larch left [113].  In
British Columbia, western larch is favored by short-rotations because of
its rapid growth on favorable sites [65].  It is a poor option for
high-elevation sites where its reliability is low, productivity is
variable, and it is subject to severe stem sweep [111].

Vegetative and reproductive buds can be distinguished by early fall,
allowing prediction of the following year's cone crop.  Descriptions of
the different types of buds and sampling procedures have been published
[25,93,103].  In British Columbia, cone collection is best in
mid-September [25].  In western Montana, the best time for cone
collection is late August to early September.  The collection period may
be extended by storing the cones and extracting seeds in October [125].
Cone production may be increased by girdling the tree.  Seeds produced
after girdling and/or fertilizing are heavier, although there may be
fewer per cone [41].

Mineral soil seedbeds may be prepared by prescribed burning or
scarification.  These treatments also reduce or delay competition
[112,116,117,118].  Seedling growth is best on north slopes under either
an open canopy or no canopy [96].  On sites with snowbrush (Ceanothus
spp.), seedlings planted in the first or second year were able to grow
as fast as the snowbrush, while natural regeneration was overtopped by
the snowbrush before it became established [128].  Western larch
seedlings survive planting better when they are dormant or close to
dormancy [129].

Overstocking is common in young stands and affects both height and
diameter growth [116].  Thinning allows trees to grow to a larger size
earlier in young, even-aged stands of western larch [121].  Thinning
from below between 10 and 15 years of age is best; thinning does not
appreciably increase growth of crop trees after 50 years of age
[14,105,120].  Removing competition by slashing increased 25-year-old
western larch height and diameter growth [42].  Thinning western larch
creates favorable conditions for shade-tolerant conifers and further
cleaning will maintain a vigorous stand [112,121].  Tables showing
average site indices for several habitat types and relationships between
height, potential d.b.h., volume, spacings, site index, and age or
habitat type are given [116].  Snow damage is normally not a problem for
this deciduous tree, as young western larch are supple and able to
recover rapidly if a late, heavy snow does occur [115].

Habitat for cavity-nesting species:  Management recommendations for
maintaining populations of cavity-nesting birds while utilizing timber
include retaining a significant number of well-scattered, old-growth
western larch, ponderosa pine (Pinus ponderosa), or black cottonwood
(Populus trichocarpa) trees [77,78].  Optimum habitat for pileated
woodpeckers seems to be a midsuccessional forest with large overstory
western larch or ponderosa pine and snags housing carpenter ants for
winter food [46].

Insects and Disease:  Larch casebearer (Coleophora laricella) and
western spruce budworm (Choristoneura fumiferana) are the most
destructive defoliating insects that feed on western larch [21,118].
While mortality due to larch casebearer is low, repeated defoliations
slow growth and may leave trees unable to maintain the dominance needed
to compete in a mixed stand.  Defoliation also increases susceptibility
to other insects and diseases [116,118,121].  The biology of and
biological controls for larch casebearer have been studied in detail
[21,22].  Biological controls and adverse weather appear to be reducing
larch casebearer populations [116].  Western spruce budworm damages
cone-bearing twigs, cones, and seeds on western larch [12,106,126].  It
also reduces height growth and damages the form of young trees by
severing terminal and lateral shoots [27,118].  Because western larch is
not a preferred species, it may gain a competitive edge during severe
spruce budworm outbreaks [79].  A number of other insects cause lesser
amounts of damage to western larch foliage and seed crops [116,118,130].

Quinine fungus (Fomitopsis officinalis) and red ring rot (Phellinus
pini) frequently cause rot in western larch [4,116,118].  Annosus root
disease (Heterobasidion annosum) is rare on western larch but has been
observed in Idaho [151].  In British Columbia, western larch is very
susceptible to laminated root rot (Phellinus weirii var. pseudotsugae)
and a shoot blight disease (Encoeliopsis laricina).  It is somewhat
susceptible to Armillaria root rot (Armillaria ostoyae) [141].  Larch
needle cast (Hypodermella laricis) and larch needle blight (Meria
laricis) both infect western larch in spring but apparently are most
severe in nurseries [36].  Many less common fungi infect western larch
[116,118].

Mistletoe:  Western larch is susceptible to larch dwarf mistletoe
(Arceuthobium laricis) but immune to other dwarf mistletoes [56,56].
This mistletoe can cause serious problems, and in eastern Oregon and
eastern Washington, 84 percent of trees are infested with dwarf
mistletoe [10,116,118].  Dwarf mistletoe increases susceptibility to
other diseases [28].  Infested trees may die following thinning [28].
The use of thinning to control dwarf mistletoe in stands with western
larch has been described [28,107].

Herbicides:  Use of mixtures of Esteron Brush Killer and diesel to
control shrubs causes t0p-kill in western larch [81].  Western larch is
susceptible to bromacil.  It is resistant to 2,4-D and 2,4,5-T when
applied as a foliar spray but susceptible to both herbicides when
applied as a basal spray [11].  Procedures for the use of maleic
hydrazide and picloram to control larch are available [49].

Related categories for Species: Larix occidentalis | Western Larch