Laminated Root Rot - Symptoms and Signs

Symptoms and Signs

Laminated root rot mainly attacks Douglas fir, Mountain hemlock, Western hemlock, Grand fir, and Pacific silver fir. The disease infects trees between 6 years and their year of rotation (the period of years between when a forest stand is established and when it receives its final harvest). Diagnostic symptoms include crown yellowing and thinning, distress of cones, red brown stained outer heartwood, and separation of annual rings. Also, plants infected with laminated root rot are usually in patches or groups since the disease is spread within a short range. Infected or decayed roots break close to the root forming “root balls.” Laminated root rot is frequently detected during ground surveying when canopy openings and standing dead and fallen trees are observed. Signs of Laminated root rot are the red fungal hairs between sheets of decomposing wood and also the buff colored mycelia on the outside of the roots.