1(a). Extraction Rate for White Fir
Mike Rutty of the Stanislaus National Forest in California figured he needed 1,800 bushels of white fir cones to yeild 1,810 pounds of seeds, a five-year supply. He started collecting aerially but after collecting only 982 bushels, half of his volume target, his helicopter was called away to fight a forest fire. When the helicopter returned six hot days later, the cones were already opening so he collected only 107 bushels more before he cancelled the project. Expecting to get a pound of seed from each bushel (an extraction rate of 1.0), Mike got a big surprise when the extraction rates for his 982 bushels came back.
What extraction rate [pounds of seed per bushel of cones] would you expect when the cones are picked at the peak of ripeness from the tops of the trees, where the best cones grow?
(Click on your guess)
In eight days of picking with a large helicopter, Mike picked 1,080 bushels of cones from a broad base of 1,168 trees. His peak collection rate was 72 bushels in one hour. Had he used any other method he would have had to collect seeds every year, even when the crop was lighter and consequently much more expensive.
Do you expect the germination rate of cones collected with Fandrich aerial rakes to be
worse or the same as or
better than cones collected by other methods?
The 1,216 bushels of cones collected in eight days produced 2,910 pounds of seeds.
To find out what the forest supervisor wrote at the end of the project,
click here .
This page was last updated July 18, 2000