THE AUTHORS 



ALAN E. HARVEY is a supervisory plant pathologist, Inter- 

 mountain Research Station, Forest Service. U.S. Depart- 

 ment of Agriculture, Ogden, UT, located in Moscow, ID. 



JOYCE A. SCHLIETER is a statistician for the Intermoun- 

 tain Research Station, located in Missoula, MT. 



MARTIN F. JURGENSEN is a professor of forest soils, 

 School of Forestry and Wood Products, Michigan 

 Technological University, Houghton. 



MICHAEL J. LARSEN is a principal mycologist. Center for 

 Forest Mycology Research, Forest Products Laboratory, 

 Forest Service, U.S. Department of Agriculture, Madison, 

 Wl. 



RESEARCH SUMMARY 



An examination of the distribution of active ectomy- 

 corrhizal short roots among soil components of eight 

 old-growth stands representative of the important timber 

 growing lands of the Inland Northwest revealed a dispro- 

 portionate concentration in surface organic materials. A 

 similar concentration in the forest floor was present in six 

 second-growth stands of various ages from the subalpine 

 fir and Douglas-fir habitat series of western Montana. Ex- 

 ceptions to this trend were noted only in an extremely dry, 

 old-growth, ponderosa pine stand and a highly disturbed 

 site regenerating to a pure stand of young western larch. 

 Even in these exceptional cases, ectomycorrhizal activities 

 were concentrated in shallow mineral horizons relatively 

 rich in organic materials. There was considerable variation 

 in the quantity of soil organic materials on the 14 sites. In 

 general, harsh and disturbed sites tended to have the 

 least. The relative proportions of soil organic components 

 (litter, humus, decayed wood) changed significantly both 

 within and between sites. Distribution of active ectomycor- 

 rhizal short roots among those components during the 

 early summer months was also significantly different, both 

 within and between sites. Approximately 75 percent of ac- 

 tive ectomycorrhizal short roots occurred in organic 

 materials that represented only the first 4 cm of the soil 

 depth. This disproportionate role of surface organic 

 materials in supporting critical symbiotic processes em- 

 phasizes the need to carefully manage this important soil 

 resource in forested ecosystems throughout the Inland 

 West. 



Intermountain Research Station 

 324 25th Street 

 Ogden, UT 84401 



