Kayla Herriman, Extractory Manager, US Forest Service, Deschutes National Forest, Bend Seed Extractory
The Bend Seed Extractory (BSE), a facility of the US Forest Service, Pacific Northwest Region located in Bend, Oregon is dedicated to seed and only seed. The facility provides a variety of services to public agencies across the United States. We extract, process, test, package, and store seed for more than 3,000 different species and our seed lots vary from a few tablespoons to thousands of pounds.
Clients provide us with raw materials and detailed collection material. Our first step is to assess the collection and determine the best process for extracting the seed. Next, we extract the seed by hand or by using various seed cleaning machines. The released seed is then finished by focusing on the removal of inert material based on shape, size, weight, or texture. Each seed lot is then tested in-house for percent purity, seeds per pound, percent filled seed, and percent equilibrium relative humidity to determine whether additional drying is required prior to storage. When new species are received, we assess them in regard to seed properties to determine the best processing method. This results in added processing time, but we are then able to develop an efficient protocol that will not damage the seeds and that can be used in the future.
Eriophyllum lanatum, common woolly sunflower, in bloom at the BSE pollinator garden, raw material prior to processing, extracted seed and finished seed. Packaged seed ready for storage
Processed seed is then used by the client for a variety of projects which could include landscape restoration, habitat enhancement, research, or gene conservation.
During the 2016 seed season we processed 13,217 pounds of raw material from native grasses, forbs, and shrubs. We also processed 7,651 bushels of conifer cones. This resulted in more than 7,500 pounds of clean seed of 811 species for restoration work across the country.
Below are descriptions and photographs of two commonly used machines for cleaning seeds, the single deck vibratory separator and a continuous seed blower, their operation, and advantages and disadvantages. Similar descriptions of other equipment items in the BSE will be added to the INSR website at a later date.
Single Deck Vibratory Separator
This single deck vibratory separator allows us to process the smallest seed with almost no seed loss here at the Bend Seed Extractory. We often use it for finishing Juncus lots, because their seed is so small. This machine also allows us to remove larvae that is the same size and weight as the seed, because the larvae often have ridges on their surface and they will move along the surface rather than roll. This machine is developed by Mater Seed Equipment and manufactured by OEM, Inc. in Corvallis, Oregon, USA.
This piece of equipment operates based on the vibration and the angle of the table. Seed travels from the hopper (1) along a vibrating channel onto the table (2). The texture, angle (3), and vibration (4) of the table are all adjustable as well as the height and speed of the feeder (4). We have multiple options for the surface including a smooth mirror, various sizes of sand paper, and different fabrics including canvas and velvet. The smooth material often drops off the feeder, rolls down the slope of the table, and then falls into a container (5). Coarse inert materials, such as leaves and flower parts, do not roll and are pushed to the top of the table where they drop into a separate container (6).
Advantages to this machine: few crevices that trap seed, easy to clean, processes even very small seed, and various adjustable surfaces are available.
Limitations to the machine: the surface can build static electricity; material cannot be over ½” in diameter, and processing can be time consuming as the material must be fed slowly and evenly.
Continuous Seed Blowers (CSB)
Continuous seed blowers (CSB) are an essential part of our finishing process at the Bend Seed Extractory. They are used most often on small collections that require fine air adjustments to remove inert material or empty seed. This machine is developed by Mater Seed Equipment and manufactured by OEM, Inc. in Corvallis, Oregon, USA.
This piece of equipment operates solely on air adjustments. Seed travels from the hopper (1) along a vibrating channel into a plastic column (2) where it hits air being blown from a motor below (3). The air settings and the feed are both adjustable. The heaviest material drops, hits a screen suspended in the plastic column, and then falls into a container (4). The lighter material is caught by the air, pushed to the top of the machine, and dropped into a separate container (5).
Advantages to this machine: there are very few crevices that trap seed, it is easy to clean, and the air adjustments are very fine tuned, allowing for precise cleaning of very small seed.
Limitations to the machine: the air column can build static electricity, material cannot be over ½” in diameter, and processing can be time consuming as material must be fed through slowly and evenly.