PNW 684 by Chal Landgren Available Online only
This publication outlines how trees grow and the culturing practices necessary to develop the size, shape, and density of true fir, Douglas-fir, pine, and spruce Christmas trees so that they are marketable.
Below are links to articles published in The Christmas Tree Lookout by the Pacific Northwest Christmas Tree Association. These articles were written by many industry professionals about past and ongoing progeny trials in the Northwest. They contain interesting information on several Christmas tree species including Douglas-fir, Noble fir, Nordmann and Turkish fir.