Subalpine larch Larix lyallii
Cone photo courtesy of L. lyallii fact sheet at Virginia Tech Forestry Department: http://www.cnr.vt.edu/dendro/dendrology/Syllabus2/factsheet.cfm?ID=680 Branch photos courtesy of Dr. R. Beal at FVCC (background): http://www.fvcc.edu/academics/botany/RockyMountainFlora/images/ETHtml.htm, and the Washington Native plant society (inlay): http://www.wnps.org/plants/larix_lyallii.html

Range

Two ranges exist, one in the North Cascades of Washington and the other in the Rocky mountains throughout Alberta, British Columbia, Idaho, and Montana ^(5). In the Cascades, L. lyallii is found east of the Cascade Divide from the Wenatchee Mountains (47° 25’N) to about 21 km into British Columbia ^(2). In the Rockies, L. lyallii extends from the Salmon River Mountains of central Idaho (45° 28’ N) northward to latitude 51° 36 in Canada ^(2).

Range photo courtesy of the Gymnosperm Database: http://www.botanik.uni-bonn.de/conifers/pi/la/lyallii.htm

Climate, Elevation

In its ranges, found from 1800 to 2400 meters (5900 – 7800 feet), and locally common on exposed northern alpine slopes to timberline ⁽⁵⁾. Grows in a very cold, snowy and moist climate, where for more than half the year, temperatures are below freezing and mean annual precipitation is 800 - 1900 mm ⁽²⁾. “Most alpine larch stands annually experience winds reaching hurricane velocity, 117 km/h (73 mi/h) or more” ⁽⁵⁾.

Local occurrence (where, how common)

Its uncommon and highly discontinuous distribution shows this species is adapted to a time when cooler, more extensive timberline habitat existed ⁽³⁾. “Many very fine stands are to be found in the eastern Cascade Mountains, including the Alpine Lakes, Glacier Peak and Pasayten Wildernesses, North Cascades National Park (WA), and Manning Provincial Park (BC)” ⁽⁵⁾.

Habitat preferences

Grows in and near timberline on high mountains of the Pacific Northwest, and is more commonly found on exposed northern slopes ⁽²⁾, ⁽⁵⁾. “Prefers an open airy position in a light or gravelly well-drained soil” ⁽⁴⁾

Plant strategy type/successional stage (stress-tolerator, competitor, weedy/colonizer, seral, late successional)

Very low shade and fire tolerance ⁽⁵⁾. Seral and “unable to compete with a vigorous growth of evergreens” ⁽²⁾. “Alpine larch is an intolerant, native, deciduous, coniferous tree”, and can be thought of as a pioneer species ⁽³⁾. It is superior in hardiness, and resists winter desiccation because it is deciduous, thus occupying a vacant niche in the highest of elevations and representing the potential climax ⁽²⁾.

Associated species

“Alpine larch is a dominant species occupying the timberline habitat type within the subalpine fir (Abies lasiocarpa) series”; associates primarily with whitebark pine (Pinus albicaulis), subalpine fir, and Engelmann spruce (Picea engelmannii). Major associated undergrowth species include mountain-heather (Phyllodoce empetriformis), smooth woodrush (Luzula hitchcockii), and grouse whortleberry (Vaccinium scoparium). (3) 

May be collected as: (seed, layered, divisions, etc.)

L. lyallii does not reproduce from sprouts ⁽²⁾, and it very rarely layers (has occurred in instances of krummholz) ⁽³⁾. Collect as seed.

Collection restrictions or guidelines

Collect in September ⁽²⁾. Large or modest seed crops are infrequent ⁽³⁾. L. lyallii does not produce appreciable quantities of seed until it is about 80 years old and dominant ⁽²⁾.

Seed germination (needs dormancy breaking?)

Germination occurs at 15°C ⁽¹⁾. “Seeds germinate in July soon after snowmelt”, and need full light and low temperatures ⁽³⁾. Daytime high temperatures and surface drought are lethal ⁽²⁾. “One month cold stratification helps germination” ⁽⁴⁾. Seeds are nondormant ⁽¹⁾. Needs scarification - soak seeds for 24 hours in 3% hydrogen peroxide solution ⁽³⁾.

Seed life (can be stored, short shelf-life, long shelf-life)

Seed remains viable for up to 3 years ⁽⁴⁾.

Recommended seed storage conditions

Store cold and sow in a cold frame in late winter.

Propagation recommendations (plant seeds, vegetative parts, cuttings, etc.)

Sow seeds late in winter in a cold frame of outdoor seedbed, and give seedlings light shade for the first year ⁽⁴⁾.

Soil or medium requirements (inoculum necessary?)

Germination appears most successful on a moist mineral soil surface on northern aspects. Grows on undeveloped, poor, soils; granite or quartzite talus which has not been occupied by vegetation previously. Ph = 3.5 to 5.7. “Mycorrhizal development was found on all trees...Cenococum graniforme has been identified as an ectotrophic mycorrhiza of subalpine larch” ⁽²⁾.

Installation form (form, potential for successful outcomes, cost)

Plant in early summer ⁽⁴⁾. Needs full light and low temperatures ⁽²⁾. Interestingly, height and diameter growth (NOT germination) increased when on southern slopes ⁽³⁾. Naturally, reproduction occurs rarely, and only under ideal conditions. Cannot be fully exposed to afternoon sun ⁽²⁾

Recommended planting density

Naturally, L. lyallii stocks itself in small groves at 125 to 200 mature trees per hectare (50 to 80/acre), with variable dispersion ⁽²⁾.

Care requirements after installed (water weekly, water once etc.)

Give effective weed excluding mulch and some winter protection at least one year after planting – if you cannot care for them through the winter, plant out in the summer of the following year ⁽⁴⁾.

Normal rate of growth or spread; lifespan

The height growth of a small alpine larch will average approximately 0.6

inch (1.5 cm) a year during the first 25 years ⁽³⁾. Lifespan typically 400 – 500 years, but have been found as old as 700 -1,000 years old. Vigorous saplings, 30 to 35 years old can be found 1.2 m (4 ft) tall. The largest recorded L. lyallii is 46 m (152 ft) tall in Montana’s Cabinet Range ⁽²⁾

Sources cited

(1) Baskin, Carol C.; Baskin, Jerry M. 2002. Propagation protocol for production of container Larix lyallii Palatore plants. University of Kentucky, Lexington, Kentucky. Native Plant Network. University of Idaho, College of Natural Resources, Forest Research Nursery. Moscow, ID. 25 April, 2005. <http://www.nativeplantnetwork.org>

(2) Burns, Russell M., and Barbara H. Honkala, tech. coords. 1990. Silvics of North America: Vol 1. Conifers. Agriculture Handbook 654. U.S. Department of Agriculture, Forest Service, Washington, DC. 25, April 2005. <http://www.na.fs.fed.us/spfo/pubs/silvics_manual/Volume_1/larix/lyallii.htm>

(3) “Larix lyallii”. Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service. Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). 25 April,, 2005. <http://www.fs.fed.us/database/feis/plants/tree/larlya/all.html>

(4) "Larix lyallii” GardenBed.com. Plants for a Future. 25 April, 2005. <http://gardenbed.com/l/5902.asp>.

(5) “Larix lyallii”. The Gymnosperm database home page. Ed. Earle, Christopher J. 27 February, 2004. 25 April, 2005. http://www.conifers.org/pi/la/lyallii.htm

Data compiled by (student name and date)

Ivona Kaczynski, April 2005