Larix (occidentalis)
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Kasten Dumroese Research Plant Physiologist USDA Forest Service, Southern Research Station 1221 S. Main St. Moscow, Idaho 83843 (208) 883-2324 kdumroese@fs.fed.us http://plant-materials.nrcs.usda.gov/copmc/ |
| Family Scientific Name: | Pinaceae | ||
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| Family Common Name: | Pine Family | ||
| Scientific Name: | Larix occidentalis Nutt. | ||
| Common Name: | Western larch | ||
| Species Code: | LAROCC | ||
| Ecotype: | Northern Idaho | ||
| General Distribution: | Western larch occurs from southeastern British Columbia and extreme western Alberta southward into eastern Washington, western Montana, northern Oregon, and northern and west-central Idaho. In northrn Idaho,this species can occur in nearly pure stands or in mixtures with Douglas-fir and western white pine. It grows best on deep, moist, porous soils in high valleys and mountain slopes of northern and western exposure. | ||
| Propagation Goal: | plants | ||
| Propagation Method: | seed | ||
| ProductType: | Container (plug) | ||
| Stock Type: | 66 ml (4 cu. in) Ray Leach "Cone-tainers" | ||
| Time To Grow: | 7 Months | ||
| Target Specifications: | Height = 20 cm Root-collar diameter = 2.8 to 3.2 mm Firm root plug | ||
| Propagule Collection: | Cones ripen from late August to early October depending on elevation. Cones can be collected by pole pruners, ladders or by climbing trees, usually just before cones open. | ||
| Propagule Processing: |
Store good cones in burlap bags and provide air circulation around the sacks. Cones can be opened without the use of a kiln by spreading them on a tarp in a warm greenhouse, or within a kiln set at 37øC (100øF) for 8 to 16 hours or at 43øC (109øF) for 7 to 9 hours. Seed wings do not detach easily without damage to seeds. Seeds can be especially pitchy. Seeds can be placed into refrigeration at 0.5 to 2øC (33 to 36øF)for up to 48 hours to harden resin for easy removal prior to running seeds through a fanning mill. The process falls into 7 stages as follows: (a) heating the cones to extract the seeds; (b) cooling at 0 to 2øC (32 to 36øF) for up to 48 hours; (c) dewinging, in which most resin particles are reduced to dust and drawn off by the dust collection system; (d) cooling; (e) passing over a 2-screen fanning mill; (f) further cooling; and (g) a final cleaning with a pneumatic separator, in which filled seeds are blown off, and the resin falls out. Small seedlots can be de-winged by gently rubbing seeds inside a moistened cotton bag. Empty seeds are removed by air and gravity separation. Seeds/kg = 216,000 to434,000 (98,000 to 197,000 seeds/lb). Seeds dried to 6 to 9% seed moisture content remain viable for 25 years when stored at 1 to 3øC (33 to 37øF). |
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| Pre-Planting Treatments: |
Seeds are placed into fine mesh bags and soaked in running tap water for 48 hours to ensure imbibition. Mesh bags are placed into plastic bags and seeds are stratified (cold, moist) for 28 days at 1 to 2øC (34 to 36øF). After stratification, seeds are soaked 24 hours in running tap water. Based on cumulative germination at 14 days in a germination test, the total amount of seeds needed for the crop is determined to ensure 90% to 95% of the cells have at least one seedling. |
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| Growing Area Preparation/ Annual Practices for Perennial Crops: |
Seedlings are grown in 2 fully-controlled greenhouses. Photoperiod is extended by 300 watt incandescent lamps (15 min on/off cycles) at an intensity of 500 lux. Irrigation is applied by an overhead traveling boom system, with nozzles spaced every 40 cm. Fertilizers are injected into irrigation water with a 1:100 injector. Containers are filled with a 1:1 (v:v) Sphagnum peat moss and vermiculite medium having a pH of 4.2. Seeds are sown in late March and are immediately covered with a shallow layer of white grit or Forestry sand (6 mm deep) and immediately irrigated (acidified to a pH around 6.0) until the medium is saturated. Using a medium with low pH, irrigating with acidified water, using grit to allow air circulation around the root collar, keeping relative humidity low, and using underbench air circulation and heating reduces damping-off disease. Day-time greenhouse temperatures are maintained at 24 to 27øC (75 to 80øF), and night-time temperatures are maintained at 18øC (65øF). |
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| Establishment Phase: |
Once seedcoats begin to fall off germinating seedlings, seedlings are thinned to 1 seedling per container. Germination is usually complete within 10 to 14 days and seedcoats are shed within 21 days. Photoperiod lights remain activated. Nutrients are supplied about twice a week. During the establishment phase, seedlings are fertilized with Peters Professional Conifer Starter (7N:40P2O5:17K2O; The Scotts Company, Marysville, Ohio) and CAN-17 (liquid ammonium calcium nitrate [17N]) to supply 65 and 23 ppm N, respectively. Phosphoric acid is used to keep pH of irrigation water around 6.0. Seedlings are irrigated when blocks weigh 80% to 85% of saturated weight. At the end of week 8, medium is leached with irrigation water to remove salt build-up. Day greenhouse temperatures are maintained at 24 to 27øC (75 to 80øF) and night temperatures around 18øC (65øF). |
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| Length of Establishment Phase: | 8 weeks | ||
| Active Growth Phase: |
We have found that western larch goes through a "coasting phase" during which seedlings continue to grow, regardless of nutrient applications or moisture conditions. During the active growth phase (at 9 weeks), only micronutrients are supplied about twice a week (Fe, B, MgSO4). Nirogen fertilization is discontinued. Containers are irrigated when blocks weigh 80% to 85% of saturated weight, but this is slowly decreased so that by the time growers wish to initiate buds, containers are irrigated at about 70% saturated weight. Photoperiod control is discontinued. Medium is leached with copious amounts of irrigation water. Medium is then allowed to dry down until it is just barely moist. Day greenhouse temperatures are maintained at 21 to 24 øC (70 to 75øF) and night temperatures around 15 to 18øC (60 to 65øF). |
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| Hardening Phase: | When irrigation is necessary, micronutrients (Fe, B, MgSO4) and phosphoric acid are supplied every irrigation. Once terminal buds are apparent, calcium nitrate is supplied at the rate of 46 ppm N. After terminal bud formation, temperatures are allowed to go to ambient, but preferably under 27øC (80øF) during the day. However, minimum greenhouse temperature allowed is -2øC (28øF). Seedlings are ready to be packed in January. From mid-September until pack-out, day temperatures are kept cool as possible and we prevent night temperatures from dropping below -2øC (28øF). Seedlings are hardened for 18 to 22 weeks. | ||
| Length of Hardening Phase: | 23 weeks | ||
| Harvesting, Storage and Shipping: |
Seedlings are extracted for storage in late November through December. Seedlings are well-watered before removal but foliage should be dry before packing. Seedlings are placed within plastic bags inside waxed boxes or plastic tubs and stored at 0.5øC (33 to 34øF). Seedlings are monitored for storage mold problems. Storage molds can be reduced by packing disease-free stock, storing them for the shortest possible duration, inspecting the crop for on-set of mold, shipping seedlings with minor mold occurrence first, and keeping temperatures below freezing. |
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| Length of Storage: | 4 to 5 months | ||
| Other Comments: |
Between crops, Between crops, containers should be sterilized. We submerge Ray Leach "Cone-tainers" in hot water (75 to 85øC [167 to 185øF]) for 15 to 30 seconds to remove pathogens. This protocol was originally developed in the mid-1980s when David L. Wenny was Director of the nursery and published as Idaho Forest, Wildlife and Range Experiment Station Bulletin 42. |
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| References: |
Dumroese RK, James RL, Wenny DL. 2002. Hot water and copper coatings in reused containers decrease inoculum of Fusarium and Cylindrocarpon and increase Douglas-fir seedling growth. HortScience 37:943-947. Dumroese RK, Wenny DL. 1997. Fertilizer regimes for container-grown conifers of the Intermountain West. In: Haase DL, Rose R, coordinators and editors. Symposium proceedings, forest seedling nutrition from the nursery to the field; 1997 Oct 28-29; Corvallis, OR. Corvallis (OR): Oregon State University, Nursery Technology Cooperative. p 17-26. Wenny DL, Dumroese RK. 1987. A growing regime for containerized western larch seedlings. Moscow (ID): University of Idaho, Idaho Forest, Wildlife and Range Experiment Station. Bulletin 42. 8 p. Dumroese RK, Wenny DL. 1995. Growing western larch in a container nursery. In: Schmidt WC, McDonald KJ, compilers. Ecology and management of Larix forests: a look ahead-proceedings of an international symposium; 1992 Oct 5-9; Whitefish, MT. Ogden (UT): USDA Forest Service, Intermountain Research Station. General Technical Report INT-319. p 213-219. |
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Citation:
Dumroese, Kasten. 2009. Propagation protocol for production of Container (plug) Larix occidentalis Nutt. plants 66 ml (4 cu. in) Ray Leach "Cone-tainers"; USDA Forest Service, Southern Research Station Moscow, Idaho. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/07/02). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.
