- We have surveyed five sites for the natural farming of shiitake cultivation in the backyard or in the forest area. They quantified their yield and analyzed their edibility.- All the collected species are the same and are confirmed by morphological studies. We have found that the yields are poor in local cultivation methods.- We have obtained the correlation analysis and found that yield is highly correlated with rainfall(mm), morning relative humidity, and evening relative humidity.- To improve the yield under farmers' cultivation methods, we have developed the prediction equation. The model equation Y = a+b1 x1 + b2 x2 + b3 x3 + b4 x4 + b5 x5 works well and has been validated.We have found the suitable logs for shiitake mushroom cultivation.