It takes about a year for a seed of a douglas fir tree to grow into a seedling, the stage where it is ready to be shipped out and planted in a forest. The Placerville Nursery on Fruitridge Road, one of six in the nation run by the United States Forest Service, stores and grows seeds for every forest in California, and is beginning to ship out this year’s crop of seedlings.
The facility, said nursery manager Dave Pilz of the U.S. Forest Service, grows 15 species, from ponderosa to jefferson and douglas fir trees, on 157 acres in Camino. The nursery is responsible for all of California, with mostly government clients looking to repopulate forests after logging or wildfires.
The entire process starts with seeds or pine cones being sent from a forest to the nursery. Seeds are removed from pinecones and stored in a 0-degree freezer. The seeds are thoroughly categorized by forest, region and elevation — the seedlings go back to either the exact same area or one elevation up or section of forest over, where they will grow best, said Frank Mosbacher of the USFS. So long as they are sufficiently dry and kept cold, Pilz said, the seeds will keep for between 15 and 20 years.
When it comes time to grow, two methods are used, Pilz said. Bare-root allows the tree to grow in the ground, as normal, and is harvested by a tractor cutting into the ground, severing the roots about 8 or 9 inches under the soil. Pruning will be done to ensure the roots are the proper length. Height and width of the seedling are also taken into account. Crews put the seedling in a plastic tub and cover the tub with a wet burlap bag to keep the seedlings moist.
The other method is known as the containerized method. Seeds are planted into a block of styrofoam and set out in the sun to get the correct amount of moisture and given shade in the summer. Some species, which grow much slower, are put in greenhouses to grow the appropriate height in just a year, far more than the tree would in nature, Pilz said. A second method, uses ray leach “cone-tainers,” which look like plastic ice cream cones, instead of a styrofoam block.
When ready to harvest for shipping, the seedlings are put on a conveyer belt and a contracted crew is put to work. For bare-root, the belt is kept constantly wet, with workers spraying the seedlings with water. They would otherwise dry out and die. As they are stored without any soil, 500 are put into a paper bag. If a styrofoam block was used, a pneumatic machine is sometimes used to help push the seedling and soil out of the block, making it easier to remove on the line. The conveyer belt for containerized seedlings does not need to be wet, as the soil will retain moisture. Workers toss rejected seedlings onto the floor, while putting 10 approved seedlings into a bag and 10 bags into a wax-coated box. The boxes are sturdy enough to be reused, being sent back to the nursery after shipments are received.
Both types are then stored in a giant freezer kept just above freezing until they are ready to be shipped. A contracted driver picks up seedlings once or twice a week, Pilz said.
In its heyday, the nursery handled 16 million seeds in a year, Pilz said. “That was in response to heavy logging. Logging is thinning now, not clear cutting, so planting is not as important.” Instead, seeds are needed to combat damage from wildfires or to work on ecological projects, he said.
As an example, the Station Fire, north of Los Angeles in 2009, devastated the big cone douglas fir, which only grows in Southern California and Baja Mexico. “We had to use quite a bit of the seeds in the bank, we used almost all of it up to grow seedlings,” Pilz said. They are now collecting more seeds of the tree.
Last year saw a total of 2.3 million seeds processed, while the projection for this year is 2.2 million seeds, Pilz said. About a third will be bare root and two-thirds will be containerized. While bare root used to be more popular, containerized is now seen as being easier to plant with better results, though it is more expensive to buy from the nursery than bare root seedlings.
To meet the changing demands, the facility is doing its best to update old equipment and expand.
“We’re in the process with PG&E to get a long-term, low-interest loan to get a more efficient cooler,” Pilz said, noting that they are also looking into solar power. Space in the coolers is also rented out, such as to farms on Apple Hill, to generate more income. The nursery is also trying to expand its pinecone seed-extraction processes, particularly where seeds are soaked in water for two months. This, Pilz and Mosbacher said, mimics conditions the seeds would encounter if they were under snowpack and allows the seeds to “germinate vigorously, quickly and uniformly, which it wouldn’t do otherwise,” Pilz said. A shade house and greenhouse are also in the beginning stages of being built, they said.
With seedlings now being sent to Southern California — northern areas tend to wait until later in the spring to plant — packing the seedling for shipment is in full swing. “We take great pride in growing baby trees,” Pilz said with a smile.
Anyone wishing to volunteer or learn more about the nursery, including how to get a guided tour, can call the nursery at 530-622-9600.