Comments
provided by eFloras
Larix lyallii and L . occidentalis ( Larix sect. Multiseriales ) are similar morphologically and have similar geographic ranges. Just how closely the two species are related has not been determined, but they probably originated from a common ancestor resembling L . potaninii Batalin. Although the geographic ranges of the two species overlap considerably, elevational differences of 150 to 300m usually separate them. Some morphologically intermediate specimens have been collected from Washington and Montana.
Because of its restricted distribution and growth at timberline, alpine larch has no commercial importance; it is often dwarfed and misshapen.
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Description
provided by eFloras
Trees to 25m; trunk to 1.2m diam.; crown sparse, conic. Bark furrowed and flaking into red- to purple-brown scales. Branches horizontal, occasionally pendulous, persistent on trunk when dead; twigs strongly white- to yellow-tomentose for 2--3 years. Buds tomentose, scale margins ciliate. Leaves of short shoots 2--3.5cm ´ 0.6--0.8mm, 0.4--0.6mm thick, keeled abaxially, 2-angled adaxially; resin canals 40--80µm from margins, each surrounded by 6--10 epithelial cells. Seed cones 2.5--4(--5) ´ 1.1--1.9cm, on curved stalks 3--7 ´ 2.5--4mm; scales 45--55, margins erose, abaxial surface tomentose; bracts tipped by awn 4--5mm, exceeding mature scales by ca. 6mm. Pollen 78--93µm diam. Seeds yellow to purple, body 3mm, wing 6mm.
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Habitat & Distribution
provided by eFloras
Subalpine talus slopes; 1800--2400m; Alta., B.C.; Idaho, Mont., Wash.
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Common Names
provided by Fire Effects Information System Plants
More info for the term:
treesubalpine larch
alpine larch
lyall larch
lyall's larch
tamarack
timberline larch
woolly larch
TAXONOMY:
The scientific name of subalpine larch is Larix lyallii Parl [
20].
There are no recognized subspecies, varieties, or forms of subalpine
larch. Hybridization with western larch (Larix occidentalis)
results in a genetically different tree [
2,
6,
7]. Although these hybrids
occupy a similar geographic area, they inhabit different altitudinal
zones, separated from each other by 500 to 1,000 feet (150-300 m) [
2].
Differentiation between subalpine larch and hybrids can be determined by
analyzing the foliar terpenes and volatiles [
7,
15].
LIFE FORM:
Tree
FEDERAL LEGAL STATUS:
No special status
OTHER STATUS:
NO-ENTRY
DISTRIBUTION AND OCCURRENCE
SPECIES: Larix lyallii
GENERAL DISTRIBUTION:
Subalpine larch occupies two mountain systems: the northern Rockies and
northern Cascades [
3,
16]. It can be found on high mountains in southern
British Columbia and Alberta, north-central Washington, north-central
and east-central Idaho, and western Montana [
1,
13,
23]. Subalpine larch
exhibits a highly discontinuous distribution, which is believed to be a
remnant of a continuous range existing at a time when cooler, more
extensive timberline habitat existed [
1,
3]. Typical subalpine larch stands
are often isolated pockets of open, parklike groves, less than 0.05 acre
(0.2 ha) [
3].
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Distribution
provided by Fire Effects Information System Plants
More info for the term:
forestSubalpine larch occupies two mountain systems: the northern Rockies and
northern Cascades [
3,
16]. It can be found on high mountains in southern
British Columbia and Alberta, north-central Washington, north-central
and east-central Idaho, and western Montana [
1,
13,
23]. Subalpine larch
exhibits a highly discontinuous distribution, which is believed to be a
remnant of a continuous range existing at a time when cooler, more
extensive timberline habitat existed [
1,
3]. Typical subalpine larch stands
are often isolated pockets of open, parklike groves, less than 0.05 acre
(0.2 ha) [
3].
Distribution of subalpine larch. 1971 USDA, Forest Service map digitized by Thompson and others [
29].
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Key Plant Community Associations
provided by Fire Effects Information System Plants
More info for the terms:
forest,
habitat type,
seriesSubalpine larch is a dominant species occupying the timberline habitat type
within the subalpine fir (Abies lasiocarpa) series [
23]. Principal
associates include whitebark pine (Pinus albicaulis), subalpine fir, and
Engelmann spruce (Picea engelmannii) [
3]. Major undergrowth species
include mountain-heather (Phyllodoce empetriformis), smooth woodrush
(Luzula hitchcockii), and grouse whortleberry (Vaccinium scoparium)
[
3,
9,
23]. See successional status for more information.
Publications listing subalpine larch as an indicator or dominant species in
habitat types (hts), community types (cts), or vegetation types (vts)
are listed below:
Area Classification Authority
MT forest hts Pfister & others 1977
n ID general veg. cts Cooper & others 1991
s AB general veg. vts Holland & others 1982
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Life Form
provided by Fire Effects Information System Plants
More info for the term:
treeTree
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Management considerations
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seed,
treeSubalpine larch is generally not placed under active management. Disease
or insects cause little damage to this tree. Occasionally, damage may
occur by an unidentified fly larvae (Diptera), which destroyed a heavy
seed crop in north-central Washington [
3]. It is suspected that the
larch case bearer (Coleophora laricella) will eventually spread from
lower western larch stands to subalpine larch stands [
3]. Brown heart rot
caused by Quinine fungus (Fomes officinales) is often found in alpine
larch, but not often enough to be considered prevalent. Needle blight
(Sarcotrochila alpina) and cast fungi (Hypodermella laricis) severely
infected many stands of subalpine larch in British Columbia. The most
common fungus infecting subalpine larch is an unidentified canker, similar
to the European larch canker (Dasyscypha willkommii). This fungus
creates noticeable swellings in young and mature twigs. These fungi
weaken but usually do not kill the tree [
3].
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Phenology
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More info on this topic. More info for the term:
treeThe growing season for subalpine larch lasts approximately 90 days. Bud
development is triggered by rising mean air temperature to about 39
degrees Fahrenheit (4 deg C) and can be normally expected to begin the
end of May. Shoot growth occurs mostly in July and progresses rapidly.
The height growth of a small subalpine larch will average approximately 0.6
inch (1.5 cm) a year during the first 25 years. Leaf fall and dormancy
are controlled by photoperiod. Late summer drought, however, has been
shown to induce early yellowing [
3]. Subalpine larch far outlives its
associated conifer species and usually dies as a result of being
windblown after pronounced heart rot. If lower limbs remain on the
stump, the tree can remain alive for many more decades [
3].
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Post-fire Regeneration
provided by Fire Effects Information System Plants
More info for the term:
seedoff-site colonizer; seed carried by wind; postfire years 1 and 2
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Taxonomy
provided by Fire Effects Information System Plants
More info for the term:
treeThe scientific name of subalpine larch is Larix lyallii Parl [
20].
There are no recognized subspecies, varieties, or forms of subalpine
larch. Hybridization with western larch (Larix occidentalis)
results in a genetically different tree [
2,
6,
7]. Although these hybrids
occupy a similar geographic area, they inhabit different altitudinal
zones, separated from each other by 500 to 1,000 feet (150-300 m) [
2].
Differentiation between subalpine larch and hybrids can be determined by
analyzing the foliar terpenes and volatiles [
7,
15].
- bibliographic citation
- Habeck, R. J. 1991. Larix lyallii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Associated Forest Cover
provided by Silvics of North America
Alpine larch grows in pure stands and also in association with whitebark
pine (Pinus albicaulis), subalpine fir (Abies lasiocarpa),
and Engelmann spruce (Picea engelmannii) near their upper
limits. Alpine larch stands are primarily considered a variant forest
cover type within Whitebark Pine (Society of American Foresters Type 208)
(26). The species is also associated with the upper elevations of
Engelmann Spruce-Subalpine Fir (Type 206), especially in the Canadian
Rockies. Near the crest of the Cascades, alpine larch is often associated
with mountain hemlock (Tsuga mertensiana) and subalpine fir.
In Montana, stands above forest line (where subalpine fir is severely
stunted) make up the Larix lyallii-Abies lasiocarpa habitat types
classified by Pfister and others (20). Alpine larch stands below forest
line (in the subalpine fir zone) are classified generally as an edaphic
(rock substrate) climax within the broader Abies lasiocarpa/Luzula
hitchcockii habitat type, Menziesia ferruginea phase.
Four species dominate in the undergrowth of most alpine larch stands
throughout the Pacific Northwest: grouse whortleberry (Vaccinium
scoparium); smooth woodrush (Luzula hitchcockii); mountain
arnica (Arnica latifolia); and red mountain heath (Phyllodoce
empetriformis) (2). But undergrowth beneath larch stands on bogs,
recent moraines, alpine tundra, or rockpile sites, is distinctively
different. Often shrublike (krummholz) subalpine fir and whitebark pine
form an undergrowth layer beneath the larch on relatively cold or
wind-exposed sites.
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Climate
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Alpine larch grows in a very cold, snowy, and generally moist climate.
The following description is based on weather records from several sites
in and near alpine larch stands (2). For more than half of the year, mean
temperatures are below freezing. The cool "growing season," as
defined by mean temperatures of more than 6° C (42° F) (6),
lasts about 90 days, and occasional frosts and snowfalls occur during the
summer. July mean temperatures range from about 9° to 14° C (48°
to 58° F). Long-term record low temperatures for late June through
mid-August are near -5° C (23° F), whereas corresponding record
highs are near 27° C (80° F). January mean temperatures range
from about -14° C (7° F) in Alberta to -7° C (20° F)
in the northern Cascades. Long-term record low temperatures have
undoubtedly reached -50° C (-58° F) in some stands near the
Continental Divide in Alberta and Montana.
Mean annual precipitation for most alpine larch sites is between 800 and
1900 mm (32 and 75 in), the larger amount being more prevalent near the
crest of the Cascades. Most stands in the Montana Bitterroot Range
evidently receive 1000 to 1500 mm (40 to 60 in). About 75 percent of this
precipitation is snow and sleet.
Typically, the new snowpack begins to accumulate by late October. By
mid-April, it reaches a maximum depth averaging about 2.1 m (7 ft) in
stands near the Continental Divide and 3.0 to 3.5 m (10 to 11 ft) farther
west. Maximum water content of the snowpack is attained in May and reaches
about 75 cm (30 in) in stands near the Continental Divide and 100 to 125
cm. (40 to 50 in) farther west. The snowpack does not melt away in most
stands until early July. Average annual snowfall is probably about 1000 cm
(400 in) in most stands west of the Continental Divide. Small amounts of
stunted alpine larch grow on wind-exposed ridgetops and other microsites
where snow accumulation is much less than the averages indicated above.
The inland Pacific Northwest often has a droughty period for a few weeks
in late summer. This drought effect is minor in most alpine larch sites;
however, dry surface soils may prevent seedling establishment in certain
years. A modest quantity of rain falls through July and August, averaging
25 to 50 mm (1 to 2 in) per month in the United States, much of it
associated with thunderstorms. In the Canadian Rockies summer
precipitation is greater, 50 to 90 mm (2.0 to 3.5 in) per month, and more
of it comes in Pacific frontal systems. Summertime relative humidity in
alpine larch stands remains consistently higher than that recorded at
lower elevations.
Most alpine larch stands annually experience winds reaching hurricane
velocity, 117 km/h (73 mi/h) or more, during thunderstorms or during the
passage of frontal systems. Ridgetop stands are exposed to violent winds
most frequently.
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Damaging Agents
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Violent winds in alpine larch stands often
damage crowns in conjunction with loads of clinging ice or wet snow.
Nevertheless this tree's deciduous habit and supple limbs make it more
resistant to wind damage than its associates. Death usually occurs when
advanced heart rot has so weakened the bole that high winds break off the
trunk. The quinine fungus (Fomitopsis officinalis), which causes
brown trunk rot, produces the only conks commonly found on living trunks.
This fungus is evidently the source of most heart rot.
Other diseases and insects generally cause little damage to alpine
larch. Needle blight fungi, Sarcotrochila alpina, has severely
infected trees on Mount Frosty in Manning Provincial Park, BC (33). Needle
cast fungi, Lophodermiurn laricinum, have also been reported on
alpine larch. Alpine larch is listed as a host of two fungi, Lachnellula
occidentalis and L. suecica (13), which may be capable of
causing stem cankers, but neither has been noted as a serious disease
problem.
Isolated witches'-brooms (dense branch-clusters with associated branch
swelling) are found widely scattered in alpine larch stands. These could
be caused by dwarf mistletoe, fungal infection, or perhaps even genetic
aberration. The western larch dwarf mistletoe Arceuthobium laricis
was reported in two early 1900's collections on alpine larch, but its
status on this species is poorly known (14).
Snow avalanches and snowslides are an important source of damage in many
stands, but again this species is better adapted to survive these
disturbances than its evergreen associates. Alpine larch poles up to 13 cm
(5 in) thick and 6 m (20 ft) tall can survive annual flattening by
snowslides only to straighten again when the snow melts in summer (4). As
larch poles exceed this size their strong trunks and lack of dense foliage
make them resistant to breakage in snowslides. Because of this superior
resistance, alpine larch often occupies snowslide sites (forming a "disclimax"
because of disturbance) within the subalpine forest proper.
Fire is an occasional but quite localized cause of injury or death in
alpine larch stands. Large fires are infrequent in these cool, moist, and
rocky sites where fire spreads poorly because of the light and
discontinuous fuels. Unlike its thick-barked, fire resistant relative,
western larch (Larix occidentalis), alpine larch has thin bark and
has low resistance to surface fire.
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Flowering and Fruiting
provided by Silvics of North America
Alpine larch is monoecious; male and
female flowers (strobili) are borne separately on short, woody spur shoots
scattered among the leaf-bearing spur shoots. Strobili are normally
monosporangiate. Buds producing the strobili begin to swell by the end of
May, and the wind-dispersed pollen is shed from the small yellowish male
strobili in June, when there is still several feet of snow on the ground
in most stands (2,21,30). Female strobili develop into purplish
cones 4 to 5 cm (1.5 to 2.0 in) long by September. Frost damage,
especially to female strobili, may account for low seed production in most
years. The importance of other factors limiting pollination,
fertilization, and seed development is unknown.
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Genetics
provided by Silvics of North America
Races, varieties, or subspecies of alpine larch are not known. The
species' restricted environmental tolerances and geographical and
altitudinal distributions may have limited the opportunity for development
of genetic variation.
Apparent natural hybridization of alpine larch and western larch has
been documented in western Montana (8,9,10). Although these species occupy
a similar geographic area, they inhabit different altitudinal zones and
are usually separated from each other by 150 to 300 m (500 to 1,000 ft) of
elevation at their closest proximities. Nevertheless, their distributions
occasionally overlap slightly in north-slope snowslide chutes or talus
rockpiles. Apparent natural hybrids have been identified in two overlap
areas using a hybrid-index formula. The two species were also artificially
cross-pollinated and the resulting seed and that from control species was
planted. Distinct morphological differences were noted among the two
species and the putative hybrid. The two species also vary in external and
internal characteristics even when they grow side by side, confirming
their genetic difference (8,9).
An interesting mixture of both larch species and various intermediate
(hybrid) forms occurs on a rocky site in the Carlton Ridge Research
Natural Area in the Lolo National Forest south of Missoula, MT (10).
The chromosome complement of subalpine larch is 2N=24, similar to that
of most other trees in the pine family (Pinaceae) (7).
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Growth and Yield
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Alpine larch is a very slow-growing,
long-lived tree. Vigorous saplings 1.2 m (4 ft) tall are about 30 to 35
years of age. Dominant trees attain small to moderate dimensions,
depending upon site conditions, in a typical 400- to 500-year life span.
Average ages for dominant alpine larch of different diameters are as
follows (2):
D.b.h.
Total age
Average
site
Very good
site
cm
in
years
13
5
150
75
25
10
250
125
38
15
350
175
51
20
500
225
99
39
-
450
The largest diameter shown is not attained on "average" sites.
Although from four to five centuries is a common life span for dominant
trees, many individuals attain 700 years, and the oldest are estimated to
be about 1,000 years (2). Complete ring counts are not possible on the
oldest trees because of extensive heart rot. On average sites (high on
north-facing slopes) the dominant trees grow 12 to 15 m (40 to 50 ft) in
height and 30 to 61 cm (12 to 24 in) in d.b.h. In moist cirque basin sites
on granitic or quartzite substrates, dominant trees reach 23 to 29 m (75
to 95 ft) in height and 61 to 124 cm (24 to 49 in) in d.b.h. The largest
recorded alpine larch, in the Wenatchee National Forest of Washington
State, is 201 cm (79 in) in d.b.h. and 29 m (95 ft) tall (1). The tallest
reported alpine larch is an exceptional 46 m (152 ft) in Montana's Cabinet
Range (3).
Alpine larch typically grows in open, parklike groves, less than 0.2 ha
(0.5 acre) in size, interspersed with natural openings of various sizes.
Stocking within the small groves is at the rate of 125 to 200 mature trees
per hectare (50 to 80/acre) (2).
No site index or yield data have been developed for alpine larch stands;
however, data from other Montana forest habitat types (20) suggest that
annual yield capability would be only about 0.7 to 1.4 m³/ha (10 to
20 ft³/acre) on sites having better than average productivity. Defect
is very high for all species in alpine larch communities. Essentially no
commercial timber harvesting has been done, even in the best developed
stands, nor does any seem likely in the future.
"Poor" alpine larch sites produce stunted larch generally 5 to
11 m (16 to 36 ft) tall at maturity.
Many of these sites lie above the tree line for evergreen conifers and
would be classified as alpine tundra were it not for the occurrence of
this unusual tree.
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Reaction to Competition
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Alpine larch is the most
shade-intolerant conifer growing at these high elevation sites and is
classed as very intolerant. Its evergreen associates attain their best
development in forests below the lower limits of larch. An exception is
whitebark pine, another timberline inhabitant, which, however, is most
abundant on warm exposures and microsites and thus tends to complement
rather than compete with larch (4). Alpine larch foliage requires higher
light intensities than its evergreen associates to maintain active growth
through photosynthesis (21,22). Thus it is unable to compete with a vigorous
growth of evergreens. Instead, alpine larch owes its existence to its
superior hardiness, especially on cool exposures. At the highest
elevations alpine larch fills a vacant niche and represents the potential
climax. The larch's ability to grow at higher elevations than evergreen
conifers on certain sites is partly related to its superior resistance to
winter desiccation-dehydration of foliage during warm, sunny periods when
the roots are still frozen or chilled (21,22). Winter desiccation in
conjunction with lack of summer warmth are thought to be primary factors
limiting the ascent of tree growth on high mountains (5,28). Above the
limit of trees, the growing season is so short that new growth cannot
adequately harden-off (fully developed cuticle), and thus it succumbs to
desiccation in winter.
Alpine larch is less vulnerable to winter desiccation than its
associated conifers because its leaves are deciduous and its buds are
woody and protected (2,21). Thus there is little tendency for larch to
grow in a shrubby or krummholz form, unlike its evergreen associates. Its
deciduous foliage requires a large amount of moisture throughout the
summer compared to the evergreens; consequently, it occupies relatively
moist sites.
In the middle of its zone of occurrence [between "forest line,"
the general upper limit of contiguous forest, and "tree line,"
the general limit of erect evergreen conifers (5)], natural openings and
severe climate allow alpine larch to share climax status with subalpine
fir, Engelmann spruce, and whitebark pine. These evergreens often develop
in the shelter of a large "patriarch" larch, sometimes growing
up through the larch crown as if it were a trellis.
On the better sites where alpine larch grows, subalpine fir is the
potential climax dominant. Engelmann spruce is usually a minor component
of stands containing subalpine larch; it often attains large size but,
unlike subalpine fir, seldom regenerates abundantly.
Occasionally alpine larch seeds in and regenerates on a burned area
within the subalpine forest, 100 to 150 m (330 to 490 ft) below its usual
elevational limits. But the species grows more slowly than the
accompanying lodgepole pine (Pinus contorta var. latifolia)
and is crowded out by that species and by subalpine fir and Engelmann
spruce.
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Rooting Habit
provided by Silvics of North America
Alpine larch roots extend deep into fissures in
the rocky substrate. Trees are well anchored by a large taproot and large
lateral roots and are very windfirm. The crown and trunk of old trees may
break off in violent winds, but the tree itself is seldom uprooted.
Richards (21) found that subalpine larch "seedlings" 16 to 25
years old and only 20 to 40 cm (8 to 16 in) tall had taproots penetrating
40 to 60 cm (16 to 24 in) and laterals descending 20 to 60 cm (8 to 24 in)
at about 45° from the horizontal. Mycorrhizal development was found
on all trees, but shallow roots had a higher degree of mycorrhizal
association than deep roots. Cenococum graniforme has been
identified as an ectotrophic mycorrhiza of subalpine larch (29).
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Seed Production and Dissemination
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Large seed crops are
infrequent. In Montana they occur about 1 year out of 10, and even
modest-sized crops occur in about the same frequency. Appreciable
quantities of seed are not produced until trees are at least 80 years old.
Dominant trees, several hundred years of age, produce the largest crops.
Most of the relatively light, winged seeds fall from the cones in
September and are wind disseminated (30). Cleaned seeds number between 231
500 and 359 500/kg (105,000 and 163,000/lb).
A heavy seed crop in one area of the Washington Cascades was largely
consumed by larvae of an unidentified fly (Diptera) (2).
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Seedling Development
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Germination of alpine larch seed has been
poor in several tests but is improved by soaking the seeds for 24 hours in
3 percent hydrogen peroxide solution (8,21,24,30). Such treatment
may inhibit root development, however (25). There are usually five
cotyledons, although four or six may appear; they are narrow, pointed, and
1.0 to 1.5 cm (0.4 to 0.6 in) long. Germination is epigeal.
First-year germinants of alpine larch are seldom found in natural
stands. In one area the smallest seedlings observed were 4 cm (1.6 in)
high and proved to be about 10 years old (4). Several cotyledon-stage
seedlings were found on an Alberta site in 1977 following a good seed year
(21).
Small openings in cirques often contain dense, even-aged groves, termed "reproduction
glades," of alpine larch seedlings or saplings. This suggests that
successful reproduction occurs rarely, and only under ideal conditions.
The location of reproduction glades suggests that germination is most
successful on a moist mineral soil surface, on northern exposures or in
cirques not fully exposed to afternoon sun. Germination probably takes
place in July soon after snowmelt.
Seedlings and basal branches of saplings have juvenile leaves that last
through two summers. Until the plants are 20 to 25 years old, this
evergreen, or "wintergreen," foliage constitutes 25 to 30
percent of the total leaf biomass (21,22). Physiological studies
suggest that this wintergreen foliage is important for tree establishment
because it is less susceptible to drought stress in summer.
Height growth is exceedingly slow for the first 20 to 25 years but
accelerates rapidly thereafter (21,22). This pattern of early
growth apparently allows the seedlings to become well established and
develop an extensive root system while still being protected from winter
and spring desiccation by the snowpack.
This species is very difficult to cultivate even in the relatively cool
climates at lower elevations in the Pacific Northwest or in England.
Seedlings have been raised at Kew Gardens (12), but they have not
grown well, leading to the conclusion that a colder climate than that of
Britain is required for alpine larch. Apparently, daytime high
temperatures and surface drought are lethal. The species seems to require
full light, but low temperatures. Bud dormancy is thought to influence the
lack of adaptation to lower elevations (17).
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Soils and Topography
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Although soil development in alpine larch stands varies, most soils are
immature. Generally alpine larch sites have undergone intense alpine
glaciation during the Pleistocene and have been deglaciated for less than
12,000 years. Chemical weathering is retarded by the short, cool summer
season. Also, nitrogen-fixing and other microbiotic activity that might
enrich the soil is apparently restricted by low soil temperatures and high
acidity.
Throughout its distribution, alpine larch commonly grows on slopes
covered with granite or quartzite talus (boulders), which have not been
previously occupied by vascular plants. The species also grows in cracks
in massive bedrock. These undeveloped soils would probably be classified
(31) as fragmental and as loamy skeletal families within the order
Entisols (Cryorthents). Such substrates have been referred to as
azonal soils, and more specifically as Lithosols in earlier
classifications.
On sites that have appreciable soil development or fine material
(including recent moraines), the soils are still rocky and immature. These
would be classified as Inceptisols-usually Typic Cryochrepts (17).
On some sheltered slopes, deposits of volcanic ash in soil profiles are
sufficiently thick to require recognition as Andic Cryochrepts, in a
medial over loamy skeletal family (15). Some of the best-developed
ash-layered soils beneath alpine larch stands are Typic Cryandepts, which
nearly fit the description of zonal Brown Podzolic soils in high elevation
forests given by Nimlos (19). These soils are strongly acidic and have a
distinct, well-developed cambic B horizon.
Throughout the range of alpine larch, pH values were found to be very
acidic, ranging from 3.9 to 5.7 in the mineral soil (B horizon) (2).
Bitterroot Range sites had an average pH of 4.6. Such strongly acid,
shallow, rocky, and cold soils are extremely infertile.
Alpine larch grows on several types of geologic substrates but has an
affinity for acidic rock types, being most abundant on granitic and
quartzite substrates and absent or scarce on nearby limestone or dolomite
(4,21). This distribution contrasts markedly with that of several other
cold-climate conifers, including Siberian larch (L. sibirica) and
tamarack (L. laricina), which often grow on basic, calcium-rich
sites (16,23).
Alpine larch achieves its best growth in high cirque basins and near the
base of talus slopes where the soils are kept moist throughout the summer
by aerated seep water. It can also tolerate boggy wet-meadow sites having
very acidic organic soils. The species is most abundant on cool,
north-facing slopes and high basins where it forms the uppermost band of
forest. It also covers broad ridgetops and grows locally under relatively
moist soil conditions on south-facing slopes. In the Canadian Rockies,
where summer rainfall is more abundant, it is often found on south slopes.
The extreme lower and upper altitudinal limits of subalpine larch, over
its entire geographic range, are apparently 1520 and 3020 m (5,000 and
9,900 ft). The lowermost individuals are found in shady cirques and
canyons in the North Cascades, while the highest limits apply to scattered
stunted trees on Trapper Peak in the Montana Bitterroot Range (2).
In the Bitterroot Range, alpine larch is abundant above 2290 m (7,500
ft) on northern exposures. It extends lowest on north-facing talus slopes,
free from other competing conifers. But, even when moist, open,
boulder-covered slopes extend down the mountainsides to the 1370 m (4,500
ft) canyon bottoms, alpine larch rarely colonizes them below 1980 m (6,500
ft).
In the Anaconda-Pintler Range of southwestern Montana, alpine larch
forms a narrow band between elevations of about 2560 and 2800 m (8,400 to
9,200 ft). Northward in the Rockies, the elevation of its timberlines
decreases gradually. Stands in northwestern Montana, Alberta, and
southeastern British Columbia are generally found between 1980 and 2380 m
(6,500 and 7,800 ft) and in the northern Cascades, between 1830 and 2290 m
(6,000 and 7,500 ft).
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Special Uses
provided by Silvics of North America
Alpine larch's primary values seem to be in watershed protection,
wildlife habitat, and outdoor recreation and esthetics. The ability of
this larch to occupy steep north slopes and snow chutes where other trees
scarcely grow suggests that it helps to stabilize snow loads and reduce
the severity of avalanches (27). Scientists from several countries
(Switzerland, Iceland, Japan, and New Zealand) who are interested in
avalanche control or forest establishment on cold sites have obtained
alpine larch seed from the USDA Forest Service.
A diverse assemblage of birds and mammals is associated with alpine
larch communities (2). Grizzly bears often dig winter dens in alpine larch
stands in Banff National Park (32). The greatest use of these habitats by
most wildlife species is as summer range, when timberline vegetation is
succulent, temperatures cool, and water abundant. Mountain goats, bighorn
sheep, hoary marmots, pikas, mule deer, elk (wapiti), black and grizzly
bears, red squirrels, and snowshoe hares are among the mammals that feed
in alpine larch stands. Blue grouse apparently feed heavily on alpine
larch needles. The trees provide some concealment and thermal cover in an
otherwise open habitat. Woodpeckers and other cavity-nesting birds and
mammals nest in the larger, hollow-trunk trees.
Hikers and photographers are attracted by the natural beauty of alpine
larch stands. The tree's foliage is a translucent bright green in summer
and turns lemon yellow and finally golden in September before it falls in
October.
The unusual hardiness of this species, its adaptations to survival in a
harsh climate, on rugged topography and sterile substrates, should make it
of special interest for scientific study and for reclamation plantings on
high-elevation sites.
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Vegetative Reproduction
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Subalpine larch does not reproduce from
sprouts. Techniques for reproduction from rooted cuttings have not been
reported. Layering (rooting of lower branches that are compressed against
moist ground) has long been known in some other species of Larix (11) and
in its associate, subalpine fir, but alpine larch is known to spread by
layering only in a few severely stunted trees or krummholz (4).
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Brief Summary
provided by Silvics of North America
Pinaceae -- Pine family
Stephen F. Arno
Alpine larch (Larix lyallii), also called subalpine larch and
Lyall larch, is a deciduous conifer. Its common name recognizes that this
species often grows higher up on cool exposures than any other trees,
thereby occupying what would otherwise be an alpine tundra. Both early-day
botanical explorers and modern visitors to the high mountains have noted
this tree's remarkable ability to form pure groves above the limits of
evergreen conifers. Alpine larch inhabits remote high-mountain terrain and
its wood has essentially no commercial value; however this tree is
ecologically interesting and esthetically attractive. Growing in a very
cold, snowy, and often windy environment, alpine larch usually remains
small and stunted, but in windsheltered basins it sometimes attains large
size-maximum 201 cm (79 in) in d.b.h. and 29 m (95 ft) in height. This
species is distinguished from its lower elevation relative western larch
(Larix occidentalis) by the woolly hairs that cover its buds and
recent twigs, and frequently by its broad, irregular crown.
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Distribution
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Alpine larch occupies a remote and rigorous environment, growing in and
near the timberline on high mountains of the inland Pacific Northwest.
Although alpine larch is found in both the Rocky Mountains and the
Cascades, the two distributions are separated at their closest points by
200 km (125 mi) in southern British Columbia. This and smaller gaps in the
species' distribution generally coincide with an absence of suitable high
mountain habitat.
In the Rocky Mountains alpine larch extends from the Salmon River
Mountains of central Idaho, latitude 45° 28' N. northward to latitude
51° 36' N. several kilometers past Lake Louise in Banff National
Park, AB. [A fossil larch, probably of this species, grew between 1000 and
1250 A.D. near the Athabasca Glacier (Columbia Icefield) 90 km (56 mi)
northwest of today's northernmost known isolated alpine larch tree (18).]
Within this distribution, alpine larch is common in the highest areas of
the Bitterroot, Anaconda-Pintler, Whitefish, and Cabinet Ranges of western
Montana. It is also found in lesser amounts atop numerous other ranges and
peaks in western Montana and northern Idaho (4). In British Columbia and
Alberta, alpine larch is common along the Continental Divide and adjacent
ranges, and in the Purcell and southern Selkirk Ranges.
In the Cascade Range alpine larch is found principally east of the
Cascade Divide and extends from the Wenatchee Mountains (47° 25' N.)
in central Washington northward to about 21 km (13 mi) inside British
Columbia (49° 12' N.). Within this limited distribution covering a
north-south distance of only 193 km (120 mi), alpine larch is locally
abundant in the Wenatchee, Chelan, and Okanogan ranges.
- The native range of alpine larch.
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Physical Description
provided by USDA PLANTS text
Tree, Deciduous, Monoecious, Habit erect, Trees without or rarely having knees, Tree with bark rough or scaly, Young shoots 3-dimensional, Buds not resinous, Leaves needle-like, Leaves alternate, Needle-like leaf margins entire (use magnification), Leaf apex acute, Leaves < 5 cm long, Leaves < 10 cm long, Leaves not blue-green, Needle-like leaves flat, Needle-like leaves not twisted, Needle-like leaf habit erect, Needle-like leaf habit drooping, Needle-like leaves per fascicle mostly 1, Needle-like leaves per fascicle > 10, Needle-like leaf sheath early deciduous, Needle-like leaf sheath persistent, Twigs tomentose, Twigs not viscid, Twigs with peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones < 5 cm long, Bracts of seed cone included, Seeds yellow, Seeds purple, Seeds winged, Seeds unequally winged, Seed wings prominent, Seed wings equal to or broader than body.
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- Stephen C. Meyers
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Larix lyallii
provided by wikipedia EN
Larix lyallii, the subalpine larch, or simply alpine larch, is a deciduous, coniferous tree native to northwestern North America. It lives at high altitudes, from 1,500 to 2,900 meters (4,900 to 9,500 ft),[2] in the Rocky Mountains of Idaho, Montana, British Columbia, and Alberta. There is a disjunct population in the Cascade Range of Washington.
Subalpine larch is hardy and can survive at low temperatures and on thin rocky soils, often being found near the tree line.[2] It can grow in a variety of soils as long as the soil is moist but well drained. However, it is relatively shade intolerant.[2]
David Lyall seems to have discovered the species between 1858 and 1861. John Bernhard Leiberg described it in 1900.[2]
Description
Larix lyallii is a small tree, growing from 10 to 25 meters (33 to 82 ft) tall and shorter at higher elevations. It has a straight trunk with a sparse and somewhat conical crown. The branches are horizontal, perpendicular to the trunk, irregularly spaced and twisted. The twigs are finely hairy. The needles are four-angled, 20 to 35 millimeters (3⁄4 to 1+1⁄2 in) long and crowded in groups of 30 to 40 on short spurs. They are pale blue-green and deciduous,[2] turning golden yellow in autumn.
The seed cones, 2.5 to 4 centimeters (1 to 1+1⁄2 in) long, are red-purple when young but become dark brown with age. They have thin scales and narrow bracts that extend over the scales. The pollen and seed cones become active in early summer.[2] The bark is about 2.5 cm thin[2] and turns from yellow-gray to dark red-brown with age. It also becomes deeply furrowed into small, scaly plates.
The tree is also one of the longest-lived tree species. There is record of a specimen in Kananaskis, Alberta, which has been understood to be about 2,000 years old, the oldest tree in Canada.[3][4]
Uses
The bark contains tannin and the wood is strong, heavy, and durable.
References
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Larix lyallii: Brief Summary
provided by wikipedia EN
Larix lyallii, the subalpine larch, or simply alpine larch, is a deciduous, coniferous tree native to northwestern North America. It lives at high altitudes, from 1,500 to 2,900 meters (4,900 to 9,500 ft), in the Rocky Mountains of Idaho, Montana, British Columbia, and Alberta. There is a disjunct population in the Cascade Range of Washington.
Subalpine larch is hardy and can survive at low temperatures and on thin rocky soils, often being found near the tree line. It can grow in a variety of soils as long as the soil is moist but well drained. However, it is relatively shade intolerant.
David Lyall seems to have discovered the species between 1858 and 1861. John Bernhard Leiberg described it in 1900.
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