Chapter 16: Monitoring Plots to Evaluate Spread Characteristics, Stand/Site Attributes, Management, and Disturbance Relationships of Black Stain Root Disease in Douglas-fir Plantations in Northern California (Project WC-EM-B-14-03)This article is part of a larger document. View the larger document here.
Black stain root disease, caused by the vascular wilt pathogen Leptographium wageneri, is widely distributed in Douglas-fir (Pseudotsuga menziesii) on substantial acreages throughout the forests of northern California and western Oregon. As a vascular wilt pathogen, Leptographium wageneri kills its hosts by growing within and plugging up the water-conductive tissues of the xylem (Hessburg and others 1995). Symptoms of the disease include the presence of individual or small groups of dead and declining trees with sparse chlorotic crowns, reduced growth, and heavy stress cone crops (fig. 16.1). Basal resinosis is another common symptom. The most common diagnostic sign of the disease is a dark brown to purple-black stain in the sapwood of infected roots and lower stems (fig. 16.2).