Umpqua Matsutake  Study 

Effects of Mushroom Harvest Technique on Subsequent American Matsutake Production

Daniel L. Luoma^a,*, Joyce L. Eberhart^a, Richard Abbott^b, Andrew Moore^c, Michael P. Amaranthus^d, David Pilz^a
aOregon State University, Department of Forest Science, Corvallis, OR  97331, USA ^bUmpqua National Forest, 2900 Stewart Parkway, Roseburg, OR  97470, USA.  ^cP.O. Box 1141, Cave Junction, OR  97523, USA.  ^dP.O. Box 1181, Grants Pass, OR  97528, USA.

Abstract

            The commercial harvest of American matsutake (Tricholoma magnivelare) is a multi-million dollar industry in the Pacific Northwest region of North America. There is considerable controversy regarding how the resource should be managed, including concerns about the cumulative effects of picking in the same areas year-after-year and whether raking of surface soil layers to find mushrooms will reduce subsequent fruiting. The objective of this study was to evaluate the effects of several mushroom harvest techniques on matsutake production.

            This study was established in the Oregon Cascades by selecting 18 matsutake shiros of similar mushroom production. Six treatments were implemented: 1) Control - no matsutake harvest, 2) Best Management Practice - harvest with minimal disturbance to the forest floor litter layer and mushrooms removed by gentle rocking and pulling, 3) Shallow Rake, Replace - shallow raking of litter layers to the top of the mineral soil surface, sporocarp removal, and replacement of the litter onto the shiro, 4) Shallow Rake, No Replace - shallow raking of litter layers, sporocarp removal without replacement of the litter, 5) Deep Rake, Replace - raking of the litter layers and raking into the top of the mineral soil (7-10 cm total depth), sporocarp removal and replacement of litter and mineral soil onto the shiro, 6) Deep Rake, No Replace - raking of the litter layers and raking into the top of the mineral soil, sporocarp removal without replacement of litter and mineral soil

            Our results demonstrate that careful picking was not detrimental to mushroom production during the initial 10 years of mushroom harvest activity.  One-time treatments in which the forest floor litter layers were removed and not replaced were strongly detrimental to matsutake production and the effects have persisted for nine years. Damage to shiros caused by repeated raking was not tested, however we expect that the effects of repeated raking would be more severe than those reported here. Negative treatment effects were particularly noticeable in years with abundant fruiting. When environmental conditions are poor for fruiting all shiros experience low production, thereby obscuring treatment effects.

            Because this study was limited to one habitat type, extension of the results to substantially different habitats types must be made with caution.  However, we speculate that since the underlying biology of matsutake fruiting is similar across a wide range of habitats, careful picking should generally not hinder subsequent fruiting when other substantial disturbance to the shiro is absent.