Ten-Year Results of Fertilizing Grand Fir, Western Hemlock, Western Larch, and Douglas-Fir with Nitrogen in Northern Idaho

摘要

Ten-year results show initial short-lived increase in growth at two locations where nitrogen fertilizer in the form of urea was applied to young stands of mixed conifers in northern Idaho. In the second 5 years after treatment there were no further significant increases between the fertilized and unfertilized trees in either diameter or height growth. Grand fir (Abies grandis) responded better in the first 5 years than any other species, while western white pine (Pinus Monticola) and western larch (Larix occidentalis) showed no evidence of response during the 10-year study.