Table 1 . Species-specific site characteristics that may be useful indicators of nutrient deficiencies. Interior species Research throughout the B.C. interior has shown that lodgepole pine is consistently deficient in nitrogen. Nitrogen additions often have a substantial positive effect on tree and stand growth. Induced boron deficiencies following nitrogen fertilization have also been documented.
Boron deficiency causes top dieback which can have a large negative impact on stem value.
The addition of a small amount of B in the operational fertilizer mix is generally effective in preventing damage. There is currently limited fertilization response information for Douglas-fir in the B.C. interior. However, results from fertilizer trials in the Intermountain region of the United States indicate that N fertilization has produced consistent growth response over a broad range of site and stand conditions. Douglas-fir stands in northern Idaho have responded very well to N additions. Factors such as crown vigor and room for crown expansion are apparently more important than age in predicting the response.