Laminated root rot in a western Washington plantation
Subtitle: 8-year mortality and growth of Douglas-fir as related to infected stumps, tree density, and fertilization
By: Richard E. Miller ... [et al].
Contributors: Miller, Richard E.; Pacific Northwest Research Station (Portland, Or.)
Series: Research paper PNW-RP -- 569.; Research paper PNW -- 569.
Publisher: U. S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station
Published: 2006
Place of publication: Portland, Or
Language: eng
Number of pages: 37
Subjects: Root rots -- Susceptibility -- Washington (State) -- Pierce County.; Douglas fir -- Roots -- Diseases and pests -- Susceptibility -- Washington (State) -- Pierce County.; Douglas fir -- Fertilizers -- Washington (State) -- Pierce County.; Phellinus -- Washington (State) -- Pierce County.
Description: A 4-year-old Douglas-fir plantation in the western Washington Cascades was monitored for 8 years after fertilization with potassium (K), nitrogen (N), and K+N to determine fertilizer effects on rates of mortality from laminated root rot (LRR) and other causes relative to a nonfertilized control. Each element was applied at a rate of 300 lb/acre on and around 0.2-acre plots replicated seven times in a randomized complete block design. Cumulative mortality from LRR did not differ significantly among fertilizer treatments, and losses were strongly related to density of infected stumps from the previous stand (r2 = 0.74). Mortality from disease and other sources accelerated during the 8 years of monitoring. Average tree growth and stand volume were greatest in treatment N and were reduced where N was combined with K. Continued monitoring is needed to identify potential longer term effects of the fertilizer treatments on susceptibility of Douglas-fir to LRR and Armillaria spp.
Notes: "November 2006."

Includes bibliographical references (p. 35-37).

Also available on the World Wide Web.