Foliage samples were secured from the upper-one third of the crowns of Douglas fir (Pseudotsuga taxifolia P.), lodgepole pine. (Pinus contorta D.), and western hemlock (Tsuga heterophylla R.) trees. Needles of the 1961, 1962, and 1963 growth were obtained with the exception of western hemlock samples at Gold River where only the current growth was collected. The needles were analyzed for the micronutrients B, Cl, Co, Cu, Fe, Mn, Mo, and Zn and for the apparently nonessential elements Al and Si.
The ranges in concentration of B, Cl, Co, Cu, Fe, Mn, Mo, Zn, Al, and Si encountered in the various needle samples were: 2.5–17.0, 73–170, 0.05–0.46, 2.1–5.6, 38.6–68.3, 293–1982, < 0.5–0.10, 3.0–52.3, 175–787, and <467–8700 ppm in the dry matter, respectively. Manganese occurred in greater amounts than any of the other 7 micronutrients. Concentration of Fe, Mn, Al, and Si generally increased with age of needles. Levels of Mn, and Al tended to be higher in needles of western hemlock than in Douglas fir. Western hemlock needles contained much less Si than Douglas fir needles.