Abstract
Element contents in wood ash from electric power plants were same level as from pellet boilers, but some elements were higher from power plants. The sand was used for the fluidized bed boiler collected in this measurement. Then, it needs to pay attention element concentration in sand when sand was used for the combustion boiler. Japanese cypress seed in the ash bed was germinated when mixing rate of the wood ash to the peat was below 1:3, but germination rate was not statistically different among media such as peat moss, coconut peat and ash with peat moss. This result indicates that production cost of container seedlings will be possible to decrease 25%. Nutrient stock in the soil and aboveground biomass of Japanese cedar and cypress stand were calculated. Calcium stock in the soil was higher than those of biomass at all sites, but potassium (K) were higher in the biomass than soil at some sites. It means that K deficiency will be occur when intensive harvesting such as whole tree harvest was conducted and will affect tree growth after harvesting. As a woody combustion ash contains high amounts of K, ash return to the forest site will supply K when harvested.
