Christmas tree cultivation tractors, and shaper sheers. Mechanized planters, at a cost of about US$4,000, are not essential but a work-saving luxury for farmers. Farmers can purchase seedlings, the lifeblood of a Christmas tree farm, from nurseries. One farmer in Oregon purchased seedlings for between US$200–300 per 1,000 plants. The farmer, a wholesaler, sold his final products for about $20 each; after the cost of the trees and other expenses, a profit of $2–3 per tree. The best-selling species in the North American market are Scots pine, Douglas-fir, noble fir, balsam fir, Fraser fir, Virginia pine, and eastern white pine, although other types
Fraser Filter Fraser Filter A Fraser Filter, named after Douglas Fraser, is typically used in geophysics when displaying VLF data. It is effectively the first derivative of the data. If formula_1 represents the collected data then formula_2 is the average of two values. Consider this value to be plotted between point 1 and point 2 and do the same with points 3 and 4: formula_3 If formula_4 represents the space between each station along the line then formula_5 is the Fraser Filter of those four values. Since formula_6 is constant, it can be ignored and the Fraser Filter considered to be formula_7.