Thuja (plicata)
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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: | Cupressaceae | ||
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| Family Common Name: | Cedar Family | ||
| Scientific Name: | Thuja plicata Donn ex. D. Donn. | ||
| Common Name: | Western redcedar | ||
| Species Code: | THUPLI | ||
| Ecotype: | Northern Idaho | ||
| General Distribution: | Western red cedar occurs from southeastern Alaska to northwestern California from the coast and Cascade Range. Inland it occurs from Prince George, British Columbia to northeastern Washington, northern Idaho and western Montana. It is a common component of coastal and mixed coniferous forests on moist sites from sea level to 2,000 m (6,000 ft). In northern Idaho, this species occurs in mixed stands with other coniferous species and grows best on moist flats and slopes and along rivers and streams. | ||
| Propagation Goal: | plants | ||
| Propagation Method: | seed | ||
| ProductType: | Container (plug) | ||
| Stock Type: | 66 ml (4 cu. in) Ray Leach "Cone-tainers" | ||
| Time To Grow: | 8 Months | ||
| Target Specifications: | Height = 20 cm Root-collar diameter = 2.5 mm Firm root plug | ||
| Propagule Collection: |
Ovulate cones are borne at the tips of branches. Ovulate cones are brown and are 1 to 1.4 cm (0.39-0.55 in) long. Seeds are light, chestnut brown and 4 to 7 mm (0.15 to 0.27 in) long with lateral wings. Seeds are wind dispersed. Trees begin producing cones at 10 years, with heavier seed production on older trees. Seed production normally begins when trees are 20 to 30 years old. Cones average about 3 to 6 seeds, but cones are often numerous and heavy seed crops are common. |
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| Propagule Processing: |
Cones can be collected during September and October from recently felled trees or by using a pole pruner on trees of medium height. Seeds can be extracted by air drying cones for 1 to 3 weeks or spreading cones on a canvas tarp outside if ventilation is good. Large nurseries use kilns set at 27 to 43ø C (80 to 109 ø F) to open cones within 24 hours. After drying, tumbling or shaking releases seeds from scales. Seeds should not be de-winged. Empty seeds are removed by air and gravity separation. Seeds/kg = 448,000 to 1,305,000 (203,000 to 592,000 seeds/lb). Seeds dried to 5 to 10% seed moisture content remain viable for 5 years when stored at temperatures of 0 to 5ø C (32 to 41ø F). For longer storage periods, storage at -18ø C (-0.4ø F) is recommended. |
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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 29øC (75 to 85øF), 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 14 to 21 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) to supply 42 ppm N, along with micronutrients (Fe, B, MgSO4). 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 to80øF) and night temperatures around 18øC (65øF). |
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| Length of Establishment Phase: | 7 weeks | ||
| Active Growth Phase: |
During the active growth phase, photoperiod control is continued. Nutrients are supplied about twice a week using Peters Professional Conifer Grower (20N:7P2O5:19K2O; The Scotts Company, Marysville, Ohio) to supply 120 ppm N, along with micros (Fe, B, MgSO4) to keep seedling height on target. If seedling height exceeds target levels, seedlings only receive micronutrients. After target heights are reached, seedlings are removed from the twice weekly fertigation schedule. Containers are irrigated at about 70 to 75% saturated weight. |
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| Length of Active Growth Phase: | 4 weeks | ||
| Hardening Phase: | Starting with week 12, the extended photoperiod is dis continued. When irrigation is necessary, calcium nitrate is applied at a rate of 46 ppm N, along with micronutrients (Fe, B, MgSO4) and phosphoric acid. Day greenhouse temperatures are now set at 15.5 to 21øC (60 to 70øF) and night temperatures of 10 to 15.5øC (50 to 60øF). By October, temperatures are allowed to go to ambient, but preferably under 27øC (80øF) during the day. However, minimum greenhouse temperature allowed is -2øC (28øF). Seedlings will have a purplish to bronze coloration at this stage. 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: | 18 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, 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 46. |
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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. Wenny DL, Dumroese RK. 1990. A growing regime for container-grown western redcedar seedlings. Moscow (ID): University of Idaho, Idaho Forest, Wildlife and Range Experiment Station. Bulletin 46. 8 p. Wenny DL, Dumroese RK. 1994. Nursery production: growing western white pine and western redcedar in greenhouses. In: Baumgartner DM, Lotan JE, Tonn JR, editors. Interior cedar-hemlock-white pine forests: ecology and management-symposium proceedings; 1993 Mar 2-4; Spokane, Washington. Pullman (WA): Washington State University Cooperative Extension. p 261-266. |
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Citation:
Dumroese, Kasten. 2009. Propagation protocol for production of Container (plug) Thuja plicata Donn ex. D. Donn. 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 2024/04/27). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.
