Decomposition of Douglas-fir logs as affected by different initial communities of bark beetles ambrosia beetles and fungi and by moisture content

Timothy Schowalter  |  4/1/2008 8:27:20 PM

Data from a National Science Foundation supported study of decomposition of Douglas-fir logs as affected by different initial communities of bark beetles, ambrosia beetles and fungi and by moisture content. Experimental Douglas-fir logs (1.5 m long x 10 cm diam) were randomly assigned to six treatments: 1) untreated control, 2) sterile 3 mm diam holes drilled 10 mm deep (through inner bark to simulate colonization by bark beetles) at 50 holes m-2, 3) sterile 3 mm diam holes drilled 37 cm deep (through sapwood to simulate colonization by ambrosia beetles) at 50 holes m-2, 4) sterile 2 mm diam holes drilled through sapwood at 50 holes m-2 and inoculated with a blend of Ascomycete (mold) fungi (Ophiostoma, Trichoderma, and Penicillium cultures), 5) sterile 2 mm diam holes drilled through sapwood at 50 holes m-2 and inoculated with a blend of Basidiomycete (decay) fungi (Stereum, Peniophora and Heterobasidion cultures), and 6) sterile 2 mm diam holes drilled through sapwood at 50 holes m-2 and inoculated with a blend of both Ascomycete and Basidiomycete fungi. These fungi are representative of initial fungal communities in decomposing logs, with Ascomycete fungi dominating logs colonized by ambrosia beetles and Basidiomycete fungi dominating logs colonized by bark beetles. Half the logs in each treatment were sheltered from precipitation with elevated clear plastic tents that extended to 40 cm above the ground. These tents intercepted precipitation but permitted normal light penetration and air flow over the logs. Measured moisture content was reduced 20% in these logs, compared to unsheltered logs. Results have been reported in:

Schowalter, T.D. and J.J. Morrell. 2002. Nutritional quality of 
            Douglas-fir wood: effect of vertical and horizontal 
            position on nutrient levels. Wood and Fiber Science 34:
            158-164.

Progar, R., T.D. Schowalter, J.J. Morrell and C.M. Freitag. 2000.  
            Respiration from coarse woody debris as affected by 
            moisture and saprotroph functional diversity in western 
            Oregon. Oecologia 124: 426-431.



Data below supports the study.
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