Dieback of a 30-year-old Douglas-fir plantation in the Brittan River Valley, British Columbia: Symptoms and diagnosis

Severe dieback and distorted growth was observed in a 30-year old plantation of coastal Douglas-fir (Pseudotsuga menziesii var Mensiesii) growing in the Brittain River Valley in southwestern coastal British Columbia. Shoot, bud and tip dieback, bushy multileadered crowns enlarged and darkened pith and red to brown discoloration on leading shoots as well as bronzed necrotic and chlorotic foliage were found to be common features of this plantation. The site characteristics of the affected plantations were found to be similar to those described by other workers as likely to result in soils low in total boron. A complete nutritional diagnosis carried out on all foliage samples collected also suggested sulphur and magnesium deficiencies.