Abstract
To promote the formation of Shiros (fungal colonies) of T. matsutake, a thinning of the understory vegetation and a ploughing of the litter layer were conducted in the stand of 25-year-old Pinus densiflora SIEB. et ZUCC., the host plant of T. matsutake. Changes of environmental factors, especially of vegetation, soil, and fungal flora, were recorded for the 10 years following the treatment. The number of Shiro of T. matsutake and its fruit body production, began to increase 7 years after the thinning. The number of Shiro increased to about 2.4 times of that on the untreated plot. Ploughing of the litter layer was ineffective in propagating Shiro. By thinning the shrubs, the forest floor became dry and light, and litter accumulation decreased. The rate of formation of the A0 layer slowed, and the fine roots of P. densiflora, increased in the mineral soil horizon. Moreover, several species of other mycorrhizal fungi and some saprophytes, which were the competitors of T. matsutake, decreased remarkably in the treated plot. The Shiro of T. matsutake can be established in young pine stands forested on infertile soil by improving the environmental factors.
