Thuja (plicata )
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Kayla Herriman Manager USDA FS - R6 Bend Seed Extractory 63095 Deschutes Market Road Bend, Oregon 97701 kayla.herriman@usda.gov http://fsweb-ochdes.r6.fs.fed.us/seedextractory/ex |
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| Family Scientific Name: | Cupressaceae | ||
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| Family Common Name: | Cypress | ||
| Scientific Name: | Thuja plicata | ||
| Common Name: | western redcedar | ||
| Species Code: | THPL | ||
| General Distribution: | Native range includes the Pacific Coast from northern California to southeastern Alaska; the Cascade Mountains in OR and WA; and the Rocky Mtns in southeastern British Columbia, NE Washington, northern Idaho, and western Montana. | ||
| Propagation Goal: | Seeds | ||
| ProductType: | Propagules (seeds, cutings, poles, etc.) | ||
| Stock Type: | seed processing | ||
| Propagule Collection: |
Cones – Cones are about 8 to 12 mm long with 5-6 pairs of scales. The 3 middle pairs are fertile and contain 2 to 3 seeds. Collection – Cones are removed from trees and stored in mesh bags, one bushel per bag or less if cones are very heavy and moist. |
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| Propagule Processing: |
Pre-Processing – Bags of cones are pre-dried on racks in a well-ventilated indoor storage area. Bags should be turned daily until significant flaring has occurred, then every other day until processing starts or it is determined that cones are fully flared. Kiln drying can be omitted if cones open naturally. If kiln drying is deemed necessary, bags should be left unopened so that seed does not fall through the screening on the bottom of the tray. Cones can be kiln dried at 90-100 degrees Fahrenheit for 6-12 hours until fully flared. Processing – *Note: Some seed technicians have had allergic reactions to THPL. Use caution if you have not worked with this species before. Extraction: Cones should only be run on the tumbler if the lot contains more than 10 bushels, which is unusual. There are many options for separating seed from cones. Each lot should be assessed separately, but consider processing efficiency, possible seed loss, and quality of the product when deciding on a method. The following are some options: 1) sieving with a combination of the large plastic sieve and small metal sieves, 2) using a hand tumbler, 3 ) running all the material over the eclipse machine with balls in the top level. Regardless of the chosen method, check cones for remaining seed before they are tossed. Repeat processing to capture additional seed if appropriate. Cones can be tumbled in the cement mixer to help dislodge seed if necessary. De-winging: Do not de-wing THPL seed. Finishing: Seeds are air-screened, using a Clipper Eclipse Model 324. First run: Top screen = 10 round, 2nd= 10 round, 3rd = 12 round, bottom = blank, Air = 15. The goal of the first run is to remove as much of the lightest and largest inert material possible without removing any filled seed. Do not worry about perfecting fill and purity until the second run. Second run: same settings as first, possibly switch top screen to a slot if inert material that is wider than the seed remains. The goal of the 2nd run is to further improve the purity and fill of the seed lot and reduce the overall volume without losing filled seed. Gravity/CSB: The Gravity Separator, Oliver Model 30 (the “new” gravity table) or the CSB, can be used to improve fill% and purity%, if standards are not able to be achieved on the eclipse or clipper. Settings vary, but seed typically requires high grading to achieve fill% over 80. Seek advice from management about how much seed loss is acceptable to achieve higher fill%. X-ray note: Seed fill can be difficult to judge on an x-ray image. Cut tests (at least 20 seed) should be used to confirm fill% on finished seed and seed to be thrown away. |
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| Other Comments: |
Average Number of Seeds per Pound: 330,508 Average percent purity: 96% Average percent fill: 83% Average estimated PLS/bushel: 132,241 *PLS calculated using fill% *This THPL information comes from 34 processing records at the Bend Seed Extractory from collections seasons 1990 through 2019. |
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Citation:
Herriman, Kayla . 2024. Propagation protocol for production of Propagules (seeds, cutings, poles, etc.) Thuja plicata Seeds seed processing; USDA FS - R6 Bend Seed Extractory Bend, Oregon. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2025/04/18). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.
