Objectives:

• To determine the efficacy of removing stumps colonized by A. ostoyae in reducing damage by Armillaria root disease in the next rotation.
• To assess the susceptibility to killing of Douglas-fir and western larch by Armillaria root disease.

Experimental Design:

Layout:

• Three blocks of about 2.5 ha each were laid out in a severely infested stand that had been partially cut three times.
• Disease centers were mapped in each block.
• After logging, stumps in two blocks were removed by a bulldozer, piled and burned; one block was root raked with a brush blade on the bulldozer.

Treatments:

• In each block 15 20 m by 20 m plots were laid out over disease centers.
• Five plots in each block were planted to Douglas-fir, five to western larch and five to a 1:1 mixture (alternate rows) of both species. Spacing was 2 m by 2 m.

History:

• 1980 - site logged
• 1981 - plots laid out
• 1982 - trees planted
• Plots are assessed for mortality and new infections in even numbered years.

Status: Active

Reports and Publications:
none to date