Fraser fir adelgid mortality. The decline of the Fraser fir in the southern Appalachians has contributed to loss of moss habitat which supports the spruce-fir moss spider. The Fraser fir is an endangered species. Threats include climate change, balsam woolly adelgid and destruction of trees for Christmas trees and timber. Although not important as a source of timber, Fraser fir is widely used as a Christmas tree. Its mild fragrance, shape, strong limbs, and ability to retain its soft needles (which do not prick easily when hanging ornaments) for a long time when cut make it one of the best trees for
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.