We studied the population dynamics of four woody species, including shrub and small trees, in the understory vegetation of Chamaecyparis obtusa plantations during the first 2-3 years after thinning. Three types of thinning at a universal thinning rate of approximately 35％ of the total number of trees were applied to each of two replication sites: intermediate to low, future tree retaining, and line thinning, The light intensity at the forest floor after thinning was as follows: future tree retaining thinning plot≒line thinning plot＞intermediate to low thinning plot＞unthinned plot. The target populations were Chengiopanax sciadophylloides, Ilex macropoda, Lindera umbellata, and Toxicodendron trichocarpa. These species were dominant and constant in each plot. For each population, we analyzed the effects of thinning on the number of new recruits, individual survival, and individual height. I. macropoda increased the number of new recruits and grew greater than the other three populations in response to thinning. Rest of the plants displayed no obvious influence from each thinning treatment on the number of new recruits or individual survival during the thinning period with significant increase on individual height growth. This suggests that the consistent shrub and small tree species in the understory of the coniferous plantations share broadly common life history strategies to maintain populations in poor lite environments.

Two cultivation trials were conducted to evaluate the feasibility of using waste beds of nameko mushrooms as a replacement for oak (Quercus serrata) sawdust in nameko mushroom bed cultivation. In the first trial, the control group used 100％ oak sawdust as the substrate (0％ replacement), while the experimental groups replaced 10, 20, 30, 50, 70, and 100％ of the sawdust with waste beds. In the second trial, as in the first, the 0％ replacement served as the control, and the experimental groups used the same substrate formulations as in the first trial, with calcium carbonate added at a dry weight of 2.03 g per cultivation bottle. The results showed that in the first trial, yield increased by approximately 25-50％, and in the second trial, by about 40-50％, compared with the 0％ replacement control. In both trials, the cultivation period was shortened by approximately one day. These findings suggest that waste nameko beds are more suitable than oak sawdust as a cultivation substrate and can be effectively used as a replacement material.

Sowing Japanese beech (Fagus crenata) seedlings annually is not recommended because of long intervals between good harvests. To ensure a stable supply, we investigated a method for controlling their growth in a nursery and maintaining an appropriate size for long-term shipping. Japanese beech seedlings were grown for five years in a nursery in Tokamachi City, Niigata Prefecture, Japan. In some plots, fertilizer was applied in the first year (additional fertilizer application), whereas in other plots, no fertilizer was applied (no additional fertilizer application), in accordance with the customary practice. Results showed that in the no-additional fertilizer treatments, seedling length and seedling diameters at the root margin were negatively affected from the first to the fifth production year. The survival rate was well maintained for five years in both treatments. The height/diameter ratio in the no-additional fertilizer treatments was lower than that in the additional fertilizer treatments from the second to the fifth production year, suggesting that a certain level of quality was maintained in the no-additional fertilizer treatments. Overall, the lack of additional fertilizer may result in suppressed Fagus crenata seedling growth but also in a more appropriate size for shipping and quality for five years in the nursery.